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Wallner K, Kearney KE, Tiwana J, Pristera N, Kim EY, Azzalini L, Sandison G, Lombardi WL, Don C, Kim M. Increased prescription dose for large vessel intravascular brachytherapy. Catheter Cardiovasc Interv 2023; 102:1034-1039. [PMID: 37855145 DOI: 10.1002/ccd.30852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 08/01/2023] [Accepted: 10/06/2023] [Indexed: 10/20/2023]
Abstract
BACKGROUND Most randomized studies testing the effectiveness of IVBT were limited to vessels less than 4 mm diameter. In fact, it is now common to treat vessels larger than 4 mm. Accordingly, the authors instituted a prescription dose increase to 34 Gy at 2 mm from source center for vessels greater than 4.0 mm. The increase in prescription dose to 34 Gy at 2 mm from center is substantial, being 50% higher than the conventional maximum of 23 Gy. AIM To take a close look at group of patients treated to 34 Gy, and for whom follow-up angiograms are available. METHODS Ten patients treated for ISR with a prescription dose of 34 Gy and for whom follow-up angiograms were available were studied. Beta-radiation brachytherapy was performed with a Novoste Beta-Cath System using a strontium-90 (beta) source (Best Vascular, Springfield, VA). Source lengths of 40 or 60 mm were used. A dose of 34 Gy was prescribed at 2 mm from the source center. RESULTS Patients were re-catheterized from 2 to 21 months (median: 16 months) following IVBT, all for symptoms suggested of restenosis. All patients had some degree of ISR of the target vessel, but no IVBT-treated vascular segment showed angiographic signs of degeneration, dissection or aneurysm. CONCLUSION The authors' clinical impression, along with detailed review of the 10 cases, suggest that using a 34 Gy prescription dose at 2 mm from source center does not result in increased toxicity.
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Affiliation(s)
- Kent Wallner
- Departments of Radiation Oncology, University of Washington, Seattle, Washington, USA
| | - Kathleen E Kearney
- Department of Medicine, Division of Cardiology, University of Washington, Seattle, Washington, USA
| | - Jasleen Tiwana
- Department of Medicine, Division of Cardiology, University of Washington, Seattle, Washington, USA
| | - Nicole Pristera
- Department of Medicine, Division of Cardiology, University of Washington, Seattle, Washington, USA
| | - Edward Y Kim
- Departments of Radiation Oncology, University of Washington, Seattle, Washington, USA
| | - Lorenzo Azzalini
- Department of Medicine, Division of Cardiology, University of Washington, Seattle, Washington, USA
| | - George Sandison
- Departments of Radiation Oncology, University of Washington, Seattle, Washington, USA
| | - William L Lombardi
- Department of Medicine, Division of Cardiology, University of Washington, Seattle, Washington, USA
| | - Creighton Don
- Department of Medicine, Division of Cardiology, University of Washington, Seattle, Washington, USA
| | - Minsun Kim
- Departments of Radiation Oncology, University of Washington, Seattle, Washington, USA
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Kyaw H, Johal G, Gedela M, Barman N, Kini A, Sharma SK. Is Coronary Brachytherapy Staging a Comeback for the Treatment of In-Stent Restenosis? Curr Cardiol Rep 2021; 23:156. [PMID: 34599432 DOI: 10.1007/s11886-021-01582-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/06/2021] [Indexed: 11/24/2022]
Abstract
PURPOSE OF REVIEW The catheter-based coronary intervention has become a well-established therapeutic modality for obstructive coronary artery disease. However, in-stent restenosis remains a significant limitation of coronary intervention despite the use of newer devices. Intravascular brachytherapy was introduced to treat recurrent in-stent restenosis but only modestly adopted. This review will discuss the mechanism of intracoronary brachytherapy, available clinical evidence of brachytherapy in recurrent in-stent restenosis treatment, and the future of coronary brachytherapy in coronary intervention. RECENT FINDINGS Drug-eluting stents have an inherent limitation as they leave a permanent metal layer inside an artery when deployed. Recently, drug-coated balloon technology has emerged to treat coronary artery disease as a combination of balloon angioplasty and local drug delivery without leaving a metal layer behind. Recent European guidelines recommended using drug-coated balloons when treating in-stent restenosis treatment, while the US guidelines have not yet addressed the use of drug-coated balloons in such cases. Coronary brachytherapy is a valuable addition to treat these challenging diseases despite several logistic issues. If there are newer technologies with easier setup, such as drug-coated balloons, coronary brachytherapy resurgence is improbable in the contemporary era, although it may not become obsolete.
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Affiliation(s)
- Htoo Kyaw
- Department of Cardiology, The Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai Hospital, One Gustave L. Levy Place, Box 1030, New York, NY, 10029-6574, USA
| | - Gurpreet Johal
- Department of Cardiology, The Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai Hospital, One Gustave L. Levy Place, Box 1030, New York, NY, 10029-6574, USA
| | - Maheedhar Gedela
- Department of Cardiology, The Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai Hospital, One Gustave L. Levy Place, Box 1030, New York, NY, 10029-6574, USA
| | - Nitin Barman
- Department of Cardiology, The Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai Hospital, One Gustave L. Levy Place, Box 1030, New York, NY, 10029-6574, USA
| | - Annapoorna Kini
- Department of Cardiology, The Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai Hospital, One Gustave L. Levy Place, Box 1030, New York, NY, 10029-6574, USA
| | - Samin K Sharma
- Department of Cardiology, The Zena and Michael A. Wiener Cardiovascular Institute, Mount Sinai Hospital, One Gustave L. Levy Place, Box 1030, New York, NY, 10029-6574, USA.
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Radiation suppresses neointimal hyperplasia through affecting proliferation and apoptosis of vascular smooth muscle cells. J Vasc Access 2017; 19:153-161. [PMID: 29192723 DOI: 10.5301/jva.5000804] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE To study the effect of x-ray radiotherapy on vascular smooth muscle cells (VSMCs) and elucidate the mechanisms in preventing neointimal hyperplasia of prosthetic vascular grafts. MATERIALS AND METHODS In model I, twelve mongrel dogs underwent revascularization with prosthetic grafts and half the dogs underwent irradiation of the grafts at 28 Gy. In model II, human VSMCs (hVSMCs) were maintained and divided into six groups to which external radiation was applied at six different doses: 0 Gy, 2 Gy, 8 Gy, 16 Gy, 24 Gy and 30 Gy. In both models, specimens were harvested and examined by using morphological, immunological, cellular and molecular methods. RESULTS After irradiation, the neointima thickness was significantly lower in irradiated groups (p≤0.01). The radiotherapy could up-regulate p27kip1, and down-regulate proliferating cell nuclear antigen (PCNA) and S phase kinase associated protein 2 (Skp2). X-ray irradiation inhibits the proliferation of hVSMCs via acting on G1/S phase of cell cycle. The apoptosis of hVSMCs increased significantly with dose and time. The expression of PCNA and Skp2 were decreased after a first increasing trend with dose, but had a significant negative correlation with time. The expression of p27kip1 had a significant positive correlation with dose and time. CONCLUSIONS Postoperative external fractionated irradiation after prosthetic vessel replacement of the abdominal aorta suppressed the development of hyperplasia in the graft neointima in the short term. There was a prominent time- and dose-dependent inhibition of VSMC proliferation by radiation when it was administered.
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Abstract
BACKGROUND Interventional treatment of arteries that are narrowed and obstructed by atherosclerosis involves either bypassing the blockage using a graft; widening the artery from the inside with a balloon, a procedure known as percutaneous transluminal angioplasty (PTA); or providing a strut to hold the vessel open, known as a stent. All of these treatments are, however, limited by the high numbers that fail within a year. Intravascular brachytherapy is the application of radiation directly to the site of vessel narrowing. It is known to inhibit the processes that lead to restenosis (narrowing) of vessels and grafts after treatment. This is an update of a review first published in 2002. OBJECTIVES To assess the efficacy of, and complications associated with, intravascular brachytherapy (IVBT) for maintaining patency after angioplasty or stent insertion in native vessels or bypass grafts of the iliac or infrainguinal arteries. SEARCH METHODS For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched their Specialised Register (last searched August 2013) and CENTRAL (2013, Issue 7). SELECTION CRITERIA Randomised controlled trials of the use of brachytherapy as an adjunct to the endovascular treatment of people with peripheral arterial disease (PAD) or stenosed bypass grafts of the iliac or infrainguinal arteries versus the procedure without brachytherapy. DATA COLLECTION AND ANALYSIS Two review authors independently assessed trial quality and two other review authors independently extracted the data. Adverse event information was collected from the trials. MAIN RESULTS Eight trials with a combined total of 1090 participants were included in this review. All included studies used the femoropopliteal artery. We did not identify any studies that used the iliac arteries. All studies compared PTA with or without stenting plus IVBT versus PTA with or without stenting alone. No trials were found comparing IVBT to technologies such as drug eluting stents or balloons, or cryoplasty. Follow-up ranged from six months to five years. The quality of the included trials was moderate with our concerns relating to the difficulty of blinding due to the nature of the procedures and the small sample sizes for some studies. Primary outcomes (patency or restenosis and need for re-intervention) were reported in the majority of the trials, but reporting at various time points and the use of multiple definitions of the outcomes by the included studies meant that not all data were available for pooling. The secondary outcomes were not reported in many of the included studies.For brachytherapy, cumulative patency was higher at 24 months (odds ratio (OR) 2.36, 95% confidence interval (CI) 1.36 to 4.10, n = 222, P = 0.002). A statistically significant difference was found for restenosis at six months (OR 0.27, 95% CI 0.11 to 0.66, n = 562, P = 0.004), 12 months (OR 0.44, 95% CI 0.28 to 0.68, n = 375, P = 0.0002) and 24 months (OR 0.41, 95% CI 0.21 to 0.78, n = 164, P = 0.007) in favour of IVBT. No difference was found after five years as measured in one study. The need for re-interventions was reported in six studies. Target lesion revascularisation was significantly reduced in trial participants treated with IVBT compared with angioplasty alone (OR 0.51, 95% CI 0.27 to 0.97, P = 0.04) at six months after the interventions. No statistically significant difference was found between the procedures on the need for re-intervention at 12 and 24 months after the procedures.A statistically significant lower number of occlusions was found in the control group at more than three months (OR 11.46, 95% CI 1.44 to 90.96, n = 363, P = 0.02) but no differences were found at less than one month nor at 12 months after the procedures making the clinical significance uncertain. Ankle brachial index was statistically significantly better for IVBT at the 12 month follow-up (mean difference 0.08, 95% CI 0.02 to 0.14, n = 100, P = 0.02) but no statistically significant differences were found at 24 hours and at six months.Quality of life, complications, limb loss, cardiovascular deaths, death from all causes, pain free walking distance and maximum walking distance on a treadmill were similar for the two arms of the trials with no statistically significant difference found between the treatment groups. AUTHORS' CONCLUSIONS The evidence for using peripheral artery brachytherapy as an adjunct to percutaneous transluminal angioplasty to maintain patency and for the prevention of restenosis in people with peripheral vascular disease is limited, mainly due to the inconsistency of assessment and reporting of clinically relevant outcomes. More data are needed on clinically relevant outcomes such as health related quality of life (HRQOL) or limb salvage and longer-term outcomes, together with comparisons with other techniques such as drug eluting balloons and stents. Adequately powered randomised controlled trials, health economics and cost-effectiveness data are required before the procedure could be recommended for widespread use.
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Affiliation(s)
| | - Monica Hansrani
- James Cook HospitalDepartment of Vascular SurgeryMiddlesboroughUK
| | - Marlene Stewart
- University of EdinburghUsher InstituteMedical School, Teviot PlaceEdinburghUKEH8 9AG
| | - Gerard Stansby
- Freeman HospitalNorthern Vascular CentreNewcastleUKNE77DN
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Roy-Chaudhury P, Arnold P, Seigel J, Misra S. From basic biology to randomized clinical trial: the Beta Radiation for Arteriovenous Graft Outflow Stenosis (BRAVO II). Semin Dial 2012; 26:227-32. [PMID: 23067015 DOI: 10.1111/sdi.12000] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The BRAVO-II study was a randomized controlled study of endovascular radiation therapy as compared to sham radiation therapy, following angioplasty of a thrombosed PRFE graft. The results did not show a benefit of endovascular radiation therapy, albeit in the context of an early termination of the study at less than 50% enrollment due to business reasons. Emphasis is laid on the fact that there may still be a role for radiation therapy in specific clinical settings associated with dialysis vascular access dysfunction.
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Affiliation(s)
- Prabir Roy-Chaudhury
- Dialysis Vascular Research Group, Division of Nephrology, University of Cincinnati and VA Medical Center, Cincinnati, Ohio, USA.
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Ahmed S, Roy-Chaudhury P. Radiation therapy for dialysis access stenosis: unfulfilled promise or false expectations. Semin Dial 2012; 25:464-9. [PMID: 22276964 DOI: 10.1111/j.1525-139x.2011.01006.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Hemodialysis vascular access dysfunction is a major cause of morbidity and hospitalization in the hemodialysis population at a cost of well over $1 billion per annum. Venous stenosis (due to venous neointimal hyperplasia [VNH]) is the most common cause of polytetrafluroethylene PTFE) dialysis access graft and arteriovenous fistula (AVF) failure. Despite the magnitude of the clinical problem, however, there are currently no effective therapies for this condition. We and others have previously demonstrated that VNH in PTFE dialysis grafts and AVF is composed of smooth muscle cells/myofibroblasts, endothelial cells within neointimal microvessels, and peri-graft macrophages. Radiation therapy blocks the proliferation and activation of all these cell types. The current review will dissect out the available in vitro, experimental, and clinical data on the use of radiation therapy for vascular stenosis in general, and for dialysis access dysfunction in particular. It is important to try and identify whether there is still a role for radiation therapy in this specific clinical setting. We believe that this is a critically important question to answer in view of the huge unmet clinical need that is currently associated with hemodialysis vascular access dysfunction.
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Affiliation(s)
- Syed Ahmed
- Dialysis Vascular Access Research Group, Division of Nephrology, University of Cincinnati, Cincinnati, Ohio 45267-0585, USA
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Wu YP, Stella PR, Chen SF, Wang YT, Wang JY, Moerland MA, Pan SD, Zhang B, Li GY, Doevendans PA, de Groot PG. β-radiation reduces the reactivity of extracellular matrix proteins in intravascular brachytherapy (IVBT), resulting in decreased platelet adhesion. Int J Cardiol 2010; 156:283-8. [PMID: 21130508 DOI: 10.1016/j.ijcard.2010.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 09/22/2010] [Accepted: 11/02/2010] [Indexed: 11/18/2022]
Abstract
BACKGROUND Intravascular Brachytherapy as a tool to reduce restenosis is thought to alter vascular wall biology and vessel wall protein function. Platelet accumulation is also indeed important in the genesis of restenosis. We examine the in vitro effects of beta-radiation on the certain vessel wall extra cellular matrix proteins. We hypothesized that vessel wall (proteins) had become less prone to thrombosis. METHODS We examined platelet adhesion to 20-Gy beta radiation treated extra cellular matrix proteins under flow conditions. Platelet flow adhesion was evaluated or quantified by image analysis, aggregation size analysis using the Watershed program and real-time fluorescence images of thrombus formation. The effect of beta radiation on vWF was further showing by measuring the binding of domain-specific antibodies to radiation treated vWF. RESULTS 20-Gy beta radiation significantly decreased platelet adhesion to extra cellular matrix protein; vWF and collagen Type III and had no effect on the adhesion upon fibrinogen and fibronectin. The beta-radiation affected mostly the AI, A2 and A3 domains of the vWF molecule on the surface, whereas the D'-D3 and B-C1 domains on the surface remain unaffected and suggesting a significant decrease in vWF binding capacity to the GPIb, heparin and collagen ligands. CONCLUSION Beta radiation treatment can alter the reactivity of the certain vessel wall extra cellular matrix proteins, in particular vWF and collagen. The vessel wall may become less prone to platelet adhesion, which results in decrease thrombus formation. It might help to reduce the onset of acute coronary occlusion after the intervention.
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Affiliation(s)
- Ya Ping Wu
- SPKLOMHNMB and Central Laboratory, Liaocheng People's Hospital, Medical School of Liaocheng, Taishan Medical University, PR China.
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Intravascular radiation therapy with a Re-188 liquid-filled balloon in patients with in-stent restenosis. Nucl Med Commun 2010; 31:746-52. [PMID: 20495498 DOI: 10.1097/mnm.0b013e32833abea8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE The aim of this study was to evaluate the feasibility and safety of intravascular radiation therapy (IVRT) using Re-188 filled balloon system in patients with in-stent stenosis. METHODS A total of 39 patients with in-stent restenosis were enrolled as the IVRT (22 patients) and control groups (17 patients) of this study after a successful coronary angioplasty. For irradiation the angioplasty balloon was replaced by a noncompliant balloon of the same diameter but 10 mm longer in length with a proximal and distal radio-opaque marker to deliver the dose of 18 Gy at 0.5 mm depth from the surface of the balloon into the vessel wall. Angiographic follow-up was performed after 6 months. RESULTS The length of the irradiated segment was between 9.14 and 22 mm and the diameter between 2.5 and 3 mm. In the IVRT group, two patients who did not receive antiplatelet therapy had myocardial infarction. Four patients who presented with stable angina earlier also had angiographically documented in-stent occlusion (two patients) and edge stenosis (two patients) of the target lesion and received angioplasty (18.1%). In the control group, three patients with recurrent angina and four asymptomatic patients had documented in-stent occlusion angiographically at 6 months and these seven patients underwent target lesion revascularization (41.2%). The overall restenosis rate in the IVRT and control groups were 23.91 and 39.86%, respectively (P=0.013). No complications were documented, except anginal pain and ST segment changes. CONCLUSION Our results indicated that the Re-188 liquid-filled balloon is feasible, safe, and effective in patients with in-stent restenosis.
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Chu CH, Hsieh BT, Chen IJ, Chen WL, Lin UT. Dosimetry study for beta-radiation treatment of in-stent restenosis. RADIATION PROTECTION DOSIMETRY 2009; 134:49-54. [PMID: 19376885 DOI: 10.1093/rpd/ncp062] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Intravascular brachytherapy (IVBT) has been recognised as a treatment modality for reducing coronary restenosis after angioplasty and stent-implantation procedures. For the treatment of in-stent restenosis using beta-emitter (188)Re, delivering adequate doses to the entire vessel wall is not possible without the potential of overdosing tissues. A method to measure the dose distribution, perturbation and percentage depth dose using plane-parallel and cylindrical tissue-equivalent phantoms has been developed. Good agreement was found between experimental results and Monte Carlo simulation performed using MCNP4C code. The dose given to the affected area in the vascular region for intravascular radiation treatment was 15-30 Gy. Dose inhomogeneity beyond the stent surface decreased significantly with increasing radial distance. In the region close to the stent outer surface (>0.5-mm radial distance), a dose reduction of 11-17% due to the stent was observed. However, the dose perturbations due to the physical properties of metallic stents were found to be significant in IVBT for in-stent restenosis by using measured dose profiles in phantoms. The method can provide accuracy in beta isotope in vivo dosimetry results for treatments involving short-range dose distributions and provide a relatively high-level spatial resolution for detection.
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Affiliation(s)
- Chien-Hau Chu
- Health Physics Division, Institute of Nuclear Energy Research, PO Box 3-10, Longtan 325, Taiwan, Republic of China
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Kim TK, Kim YJ, Park CS, Park HJ, Kim DB, Jang SW, Kim PJ, Jung HO, Baek SH, Seung KB, Choi KB. Effect of High Dose External Irradiation on the Matrix Metalloprotease-2 Expression in a Rat Carotid Artery Injury Model. Korean Circ J 2008. [DOI: 10.4070/kcj.2008.38.4.212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Tae Kyoon Kim
- Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Yong Joo Kim
- Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Chan Seok Park
- Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Hun-Jun Park
- Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Dong-Bin Kim
- Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Sung-Won Jang
- Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Pum-Joon Kim
- Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Hae-Ok Jung
- Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Sang Hong Baek
- Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Ki Bae Seung
- Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
| | - Kyu-Bo Choi
- Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea
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Zampakis P, Karnabatidis D, Kalogeropoulou C, Kardamakis DM, Katsanos K, Skouras T, Siablis D. External Beam Irradiation and Restenosis Following Femoral Stenting: Long-Term Results of a Prospective Randomized Study. Cardiovasc Intervent Radiol 2007; 30:362-9. [PMID: 17295082 DOI: 10.1007/s00270-004-0275-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE To assess the long-term outcome of external beam irradiation (EBI) for the prevention of restenosis due to neointimal hyperplasia, following percutaneous transluminal angioplasty (PTA) and stenting of the superficial femoral artery. METHODS Sixty consecutive patients with peripheral arterial disease, who were treated with "bail-out" stent implantation in the superficial femoral artery due to suboptimal PTA, were included in this study. Patients were randomly allocated into two groups, receiving either external beam irradiation (6 MV photons, total dose 24 Gy in a hypofractionated schedule) plus antiplatelet therapy (EBI group) or antiplatelet therapy alone (control group). RESULTS No procedure-related complications occurred, and all patients of the EBI group received the full dose of 24 Gy. During the long-term follow-up, an overall statistically significant difference was demonstrated in favor of the EBI group patients, regarding both the in-stent (log-rank test, p = 0.0072) and the in-segment binary restenosis (log-rank test, p = 0.0103). The primary patency rates were also significantly better in the EBI group at specific time-points, such as in the first (74.2% vs 46.5%, p = 0.019), second (62.5% vs 33.8%, p = 0.020), and third (54.6% vs 29.0%, p = 0.039) year, respectively. Moreover, the overall clinically driven reintervention rate was significantly lower among patients of the irradiated group (log-rank test, p = 0.038). CONCLUSION Our long-term follow-up analysis revealed that EBI following femoral artery PTA and stenting significantly reduces restenosis and reintervention rates, while improving primary patency.
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Affiliation(s)
- Petros Zampakis
- Department of Radiology, University Hospital of Patras Medical School, 265 00 Patras, Greece
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Van Limbergen E, Trepuraneni P. Is this the swan song of endovascular brachytherapy? Radiother Oncol 2007; 82:1-4. [PMID: 17184863 DOI: 10.1016/j.radonc.2006.11.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2006] [Accepted: 11/17/2006] [Indexed: 11/29/2022]
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Zhang J, Melhem M, Kassing W, Kelly B, Wang Y, Krishnamoorthy M, Heffelfinger S, Desai P, Roy-Chaudhury P. In vitro Paclitaxel and Radiation Effects on the Cell Types Responsible for Vascular Stenosis: A Preliminary Analysis. Blood Purif 2006; 25:155-60. [PMID: 17179736 DOI: 10.1159/000098018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2006] [Accepted: 08/02/2006] [Indexed: 11/19/2022]
Abstract
Hemodialysis vascular access dysfunction as a result of venous neointimal hyperplasia in dialysis access grafts and fistulae is currently a huge clinical problem. The aim of this study was to assess the effects of paclitaxel and radiation, both singly and in combination on the proliferation of cell types present within the lesion of venous neointimal hyperplasia (vascular smooth muscle cells, fibroblasts and endothelial cells within the neointimal microvessels). Vascular smooth muscle cells, fibroblasts and endothelial cells were plated onto 96-well plates and exposed to different concentrations and doses of paclitaxel and radiation, respectively (both individually and in combination). Growth inhibition was assessed with an MTT assay. Both paclitaxel and radiation resulted in significant growth inhibition of all three cell types. However, even small doses of paclitaxel appeared to attenuate the antiproliferative effect of radiation on these cell types. Further experiments to elucidate the mechanism behind these findings could result in a better understanding of combination antiproliferative therapies.
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Affiliation(s)
- J Zhang
- Department of Medicine, University of Cincinnati, Cincinnati, Ohio 45267-0585, USA
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Misra S, Bonan R, Pflederer T, Roy-Chaudhury P. BRAVO I: A pilot study of vascular brachytherapy in polytetrafluoroethylene dialysis access grafts. Kidney Int 2006; 70:2006-13. [PMID: 17035947 DOI: 10.1038/sj.ki.5001869] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Hemodialysis vascular access dysfunction owing to stenosis and thrombosis in polytetrafluoroethylene dialysis access grafts is a huge clinical problem for which there are currently no long lasting durable therapies. Vascular brachytherapy has been used successfully for the prevention of coronary restenosis following angioplasty and stent placement. The Beta Radiation for Treatment of Arterial-Venous Graft Outflow I study was a pilot study of vascular brachytherapy in hemodialysis patients with patent but dysfunctional grafts. Twenty-five patients were randomized to receive either radiation therapy (a single dose of 18.4 Gy) or sham radiation, following angioplasty. The primary efficacy end point of the study was target lesion primary patency at 6 months. The primary safety end point was a composite of death, emergency surgery on the graft, venous rupture, or aneurysm formation. Forty-two percent of the radiated grafts achieved the target lesion primary patency end point at 6 months as compared to 0% of the control group (P = 0.015), but this did not translate into an improvement in secondary patency at either 6 or 12 months. Radiation therapy was found to be safe in the setting of hemodialysis vascular access dysfunction. Our results suggest that vascular brachytherapy is an intervention that is worthy of further examination in the setting of non-thrombosed dialysis access grafts.
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Affiliation(s)
- S Misra
- Department of Radiology, Cardiology and Surgery, Mayo Clinic, Rochester, Minnesota, Minnesota, USA
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Ducasse E, Chevalier J, Cosset JM, Creusy C, Eschwege F, Speziale F, Sbarigia E, Midy D, Baste JC, Lartigau E. Ionizing radiation to prevent arterial intimal hyperplasia at the edges of the stent: induces necrosis and fibrosis. J Surg Res 2006; 135:331-6. [PMID: 16716353 DOI: 10.1016/j.jss.2006.03.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2006] [Revised: 03/28/2006] [Accepted: 03/29/2006] [Indexed: 11/18/2022]
Abstract
BACKGROUND Although ionizing radiation has been proposed for the prevention of intimal hyperplasia in coronary and peripheral arteries in multicenter clinical trials, information is lacking on how irradiation affects arterial histology after stenting and especially how it affects the edges of the stent. We investigated intimal hyperplasia recasting with histological changes in arterial wall at the edges of the stent after arterial stenting followed by adequate external radiation for the prevention of intimal hyperplasia in pigs. MATERIALS AND METHODS The aorta was experimentally stented in 30 pigs who were then assigned to two groups: irradiation with 20 Gy and a control group with no irradiation. The aorta was resected for morphometric and histological studies 6 weeks after procedure. RESULTS Intimal thickness was reduced and the intima/media ratio was significantly lower in irradiated groups than in control pigs. In the irradiated group histological examination at the edges of the stent showed thin neointimal proliferation with an intact endothelium. In all sections analyzed in the 20-Gy irradiated group the vascular media at 45 days contained necrotic areas and fibrosis with calcifications. CONCLUSIONS After arterial injury, adequate ionizing radiation effectively reduces neointimal thickening. Irradiation-induced histological changes include previously undetected recasting with necrosis and fibrosis at the arterial edges of the stent. The parietal recasting we observed in animal arteries irradiated at high doses is unclear and a cause of concern especially after clinical spontaneous dissection was recently reported. The use of ionizing radiation for the prevention of arterial restenosis awaits confirmation with a long-term follow-up including specific experimental histological analyses.
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Affiliation(s)
- Eric Ducasse
- Unit of Vascular Surgery, Tripode-Pellegrin Hospital, Bordeaux, France.
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16
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Dilcher C, Chan R, Justus BL, Falkenstein P, Huston AL, Waksman R. Dose mapping of porcine coronary arteries using an optical fiber dosimeter. CARDIOVASCULAR REVASCULARIZATION MEDICINE 2005; 6:163-9. [PMID: 16326378 DOI: 10.1016/j.carrev.2005.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2005] [Accepted: 10/07/2005] [Indexed: 11/15/2022]
Abstract
BACKGROUND This study is about the measurement of radiation dose contribution to the coronary arteries during intravascular brachytherapy with beta and gamma emitters utilizing in vivo optical fiber dosimeters. METHODS AND MATERIALS Domestic pigs were used. With each measurement, catheters were introduced into two different coronary arteries, including the left circumflex (LCX), the left anterior descending (LAD), the first diagonal, and/or the right coronary artery (RCA). A radioactive source (192Ir, 90Sr/Y, or 32P) and the dosimeter were loaded in each of these catheters. Data were collected as the dosimeter was being retracted at a constant rate via computer control. RESULTS The radiation dose was normalized to 100% at a 2-mm radial distance from the source. When radiating a branching artery, the dose to the bifurcation at 5 mm from the source was 35%, 10%, and 3% for the 192Ir (10 seeds), 90Sr/Y (40 mm), and 32P sources, respectively. When utilizing a 23-seed 192Ir source, the dose is 40% at a 5-mm distance. However, radiation of the RCA did not result in dosing to the LAD or LCX using any source. CONCLUSIONS The dose to adjacent artery segments is less with beta than with gamma emitters. Significant dose exposition is noted when using gamma emitters at a distance of 5 mm. The results can serve as a guideline for establishing prescription doses and safety margins for the treatment of bifurcation lesions and retreatment of the arteries.
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Affiliation(s)
- Christian Dilcher
- Division of Cardiology, Washington Hospital Center, Washington, DC, USA
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17
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Krueger K, Bendel M, Zaehringer M, Reinicke G, Lackner K. Centered endovascular irradiation to prevent postangioplasty restenosis of arteriovenous fistula in hemodialysis patients; Results of a feasibility study. ACTA ACUST UNITED AC 2005; 5:1-8. [PMID: 15275625 DOI: 10.1016/j.carrad.2004.02.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2004] [Accepted: 02/18/2004] [Indexed: 11/26/2022]
Abstract
PURPOSE To report follow-up results of a prospective trial on centered endovascular gamma-irradiation (CEGI) after percutaneous transluminal angioplasty (PTA) for stenosis of arteriovenous fistula in hemodialysis patients. METHODS AND MATERIALS Eight patients receiving PTA for recurrent (n = 4) or de novo arteriovenous fistula stenoses were treated with CEGI with iridium-192 (14 Gy). Angiography was performed after 6 and 12 months or if problems reoccurred during hemodialysis. Parameters of hemodialysis and duplex sonography were determined the day before and after PTA and after 1, 3, 6, 9, and 12 months. RESULTS CEGI was performed successfully and without complications in seven patients. In six patients, restenosis occurred 6-52 weeks (mean 20.8 +/- 17.9 weeks) after PTA and required PTA. Parameters of hemodialysis and duplex sonography deteriorated during follow-up. CONCLUSIONS Centered endovascular gamma-irradiation with iridium 192 immediately after PTA of fistula stenoses was a safe and feasible method but did not prevent restenosis.
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MESH Headings
- Aged
- Aged, 80 and over
- Angiography, Digital Subtraction
- Angioplasty, Balloon/adverse effects
- Angioplasty, Balloon/methods
- Arteriovenous Shunt, Surgical/adverse effects
- Dose-Response Relationship, Radiation
- Feasibility Studies
- Female
- Graft Occlusion, Vascular/diagnostic imaging
- Graft Occlusion, Vascular/radiotherapy
- Humans
- Iridium Radioisotopes/therapeutic use
- Kidney Failure, Chronic/diagnostic imaging
- Kidney Failure, Chronic/therapy
- Male
- Pilot Projects
- Probability
- Prospective Studies
- Renal Dialysis/adverse effects
- Renal Dialysis/methods
- Risk Assessment
- Treatment Outcome
- Vascular Patency
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Affiliation(s)
- Karsten Krueger
- Department of Radiology, University of Cologne, Joseph-Stelzmann-Street, D-50924 Cologne, Germany.
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18
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Zabakis P, Kardamakis DM, Siablis D, Kalogeropoulou C, Karnabatidis D, Malatara G, Dimopoulos IA. External beam radiation therapy reduces the rate of re-stenosis in patients treated with femoral stenting: results of a randomised study. Radiother Oncol 2005; 74:11-6. [PMID: 15683662 DOI: 10.1016/j.radonc.2004.09.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2004] [Revised: 08/24/2004] [Accepted: 09/07/2004] [Indexed: 11/20/2022]
Abstract
BACKGROUND AND PURPOSE To evaluate the feasibility and efficacy of external beam irradiation (EBI) for the prevention of re-stenosis due to neointimal hyperplasia, after percutaneous transluminal angioplasty (PTA) and stent placement of the superficial femoral artery. PATIENTS AND METHODS A total of 60 patients with the diagnosis of superficial femoral artery stenoses or occlusions due to peripheral arterial obstructive disease underwent PTA and implantation of a self-expandable stent at their superficial femoral artery. After the procedure, patients were randomised and 30 of them received EBI (6 MV photons, total dose 24 Gy in six fractions in 2 weeks), while the rest 30 received no radiation therapy. RESULTS EBI was technically feasible in all patients, without serious radiation related side effects. Overall, a statistically significant difference was observed in stenosis categories between the two groups at 6 months follow-up (P=0.04). More specifically, significantly more patients in the control group presented with stenosis greater or equal than 70% [EBI group 30% (9/30); control group 66.7% (20/30); P=0.009]. This difference in the percentage of re-stenosis had as a consequence significantly lower re-intervention rates among the patients of the irradiated group [17% (5/30) versus 47% (14/30); P=0.025] during the 6 months follow-up period. We also observed that the irradiated patients had re-stenosis at the stent ends, while the non-irradiated had re-stenosis at the stent ends and the lumen. Three of the irradiated patients, who discontinued the anti-platelet treatment, have shown thrombosis of the irradiated artery during the first month from the completion of the treatment. CONCLUSIONS It is our belief that EBI is a feasible, safe and effective method for the prevention of neointimal hyperplasia at the superficial femoral artery. Further studies are deemed necessary to optimise the radiotherapy schedule.
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Affiliation(s)
- Petros Zabakis
- Department of Radiology, University Hospital of Patras Medical School, 265 00 Patras, Greece
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19
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Park SW, Hong MK, Oh SJ, Moon DH. Intracoronary brachytherapy for in-stent restenosis: will it remain a viable therapy? Eur J Nucl Med Mol Imaging 2004; 31:1219-23. [PMID: 15205921 DOI: 10.1007/s00259-004-1567-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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20
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Heckenkamp J, Nigri GR, Waterman PR, Overhaus M, Kossodo SC, Lamuraglia GM. Gamma-irradiation modulates vascular smooth muscle cell and extracellular matrix function: Implications for neointimal development. J Vasc Surg 2004; 39:1097-103. [PMID: 15111867 DOI: 10.1016/j.jvs.2003.12.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Migration of vascular smooth muscle cells (SMCs) into the subintimal space, and their proliferation and resultant deposition of extracellular matrix are key processes in the development of intimal hyperplasia, leading to vascular recurrent stenosis. The purpose of this study was to investigate the effects of clinically administered doses of gamma-radiation on SMCs and extracellular matrix proteins in vitro, to better understand how it impinges on cellular and extracellular components of recurrent stenosis. METHODS The effects of gamma-irradiation (10, 20 Gy) on SMC migration into three-dimensional collagen matrix gels was quantitated by calibrated light microscopy, and the release of metalloproteinases into conditioned media was investigated with an enzyme-linked immunosorbent assay and zymography. Collagen production was assayed with [(3)H]-proline incorporation, and SMC phenotype changes with confocal microscopy with a fluorescent alpha-actin antibody. The effect of gamma-irradiation on extracellular matrix was investigated by quantitating untreated SMC proliferation ((3)H-thymidine incorporation) on irradiated endothelial cell-derived matrix and by assessing structural collagen matrix changes with sodium dodecylsulfate polyacrylamide gel electrophoresis. All groups were compared with nonirradiated control groups. RESULTS SMC vertical migration was significantly decreased by gamma-irradiation (48% and 55%, respectively; P <.0001). Irradiation did not generate measurable matrix protein crosslinks, nor did it alter the production of metalloproteinases or collagen synthesis. However, gamma-irradiation decreased the ability of extracellular matrix to induce nonirradiated SMC proliferation (15% reduction; P =.0028). Moreover, gamma-irradiation reversed the secretory phenotype of cultured SMCs to a contractile type. CONCLUSIONS The gamma-irradiation-induced reduction of cellular migration, changes in SMC phenotype, and functional activity of matrix-bound factors, and no measurable effects on the production of extracellular matrix proteins, may in part explain the diverse effects of gamma-irradiation on the restenotic response.
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Affiliation(s)
- Joerg Heckenkamp
- Division of Vascular Surgery of the General Surgical Services, and Wellman Laboratories of Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, Mass, USA
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Sianos G, Wijns W, de Feyter PJ, Serruys PW. Geographical miss during centered intracoronary beta-radiation with 90Yttrium: incidence and implications for recurrence rates after vascular brachytherapy for de novo lesions. ACTA ACUST UNITED AC 2004; 5:181-9. [PMID: 14630560 DOI: 10.1080/14628840310015223] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVES The authors sought to determine the incidence and causes of geographical miss (GM) and evaluate its impact on edge restenosis after 'primary', centered, intracoronary beta-radiation therapy. BACKGROUND Edge restenosis is a limitation of intracoronary beta-radiation therapy. GM occurs when the radiation source does not fully cover the injured segment and may account for this phenomenon. METHODS One hundred and eighty-one patients enrolled in the Dose-Finding study were retrospectively analyzed. The patients were randomized to receive 9, 12, 15 or 18 Gy at 1 mm tissue depth. Using quantitative coronary angiography the effective irradiated segment (EIRS) and both edges were studied prior to and after intervention, and at six-month follow-up. GM was defined as a situation where the effective radiation source length (24 mm) did not fully cover the injured segment. The edges of the EIRS that were injured during the procedure constituted the GM edges. A greater than 50% diameter stenosis at follow-up was considered significant. GM was determined by the simultaneous, electrocardiographically matched, side-by-side projection of the source and balloons in place, in identical projections surrounded by contrast. RESULTS In 16% of patients GM was noninterpretable owing to inadequate filming. GM constituted 21.1% of the interpretable edges and 40.1% of the interpretable vessels analyzed. The occurrence of restenosis in the EIRS and the analyzed vessel segment (VS) was similar between procedures with and without GM. In vessels with GM, restenosis was significantly increased from the EIRS to the VS (from 8.77% to 21%, p = 0.05) as opposed to non-GM vessels (from 11.9% to 19%, p = 0.6). GM tended to be associated with a greater incidence of significant stenosis at the edges of the EIRS (8.3% versus 4.0%, p = 0.15) compared with individuals with >50 % stenosis but no GM. This effect was more prominent at the distal edge. The relation of GM and edge restenosis was independent of dosage. CONCLUSIONS Since GM does not affect the incidence of restenosis in the EIRS, restenosis in this segment should be considered a treatment failure, probably due to inadequate dosage. GM is related to significant increase in restenosis from the EIRS to the VS. GM tends to be associated with restenosis at the edges of the EIRS. This is a local phenomenon, which is independent of dosage and which has a specific pathophysiology (combination of injury and low-dose radiation). If GM can be eliminated, the results of vascular brachytherapy will be improved.
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Ducasse E, Creusy C, Mazurier J, Cosset JM, Eschwege F, Puppinck P, Speziale F, Sbarigia E, Fiorani P, Lartigau E. Morphometric and histological changes in the vascular wall after external radiation for the prevention of intimal hyperplasia. J Surg Res 2004; 117:316-22. [PMID: 15047137 DOI: 10.1016/s0022-4804(03)00341-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2003] [Indexed: 11/30/2022]
Abstract
BACKGROUND Recent reports describe spontaneous dissections and aneurysms after coronary and peripheral artery irradiation for the prevention of intimal hyperplasia. We investigated histological changes and the vasomotor reaction in the vascular wall after external radiation for the prevention of intimal hyperplasia in rabbits. MATERIALS AND METHODS The aorta was experimentally injured in 34 rabbits who were then assigned to one of three groups: irradiation with 20 Gy; with 25 Gy; and a control group with no irradiation. Before the arterial injury and 45 days later, vasomotor function was assessed with an intravascular ultrasound catheter. The aorta was resected for morphometric and histological studies. RESULTS After injury and irradiation, vasomotor responses were significantly lower in the two irradiated groups (P < 0.05). Intimal thickness and the intima/media ratio were significantly lower in irradiated groups. In the irradiated group histological examination showed reduced intimal proliferation with an intact endothelium. In the 20-Gy irradiated group the vascular media contained necrotic areas, and in the 25-Gy irradiated group, severe fibrosis. CONCLUSION After arterial injury, external irradiation at 20 and 25 Gy effectively reduces aortic intimal and medial thickening. Histological changes include recasting with necrosis and fibrosis causing a decreased vasomotor response. Further investigations are needed to confirm medial necrosis and replacement with fibrosis. Because the irradiation doses in this study match those currently used and also recommended for experimental and clinical use, if confirmed in humans parietal recasting might possibly explain the reported spontaneous dissections and aneurysm formation after irradiation.
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Affiliation(s)
- Eric Ducasse
- Unit of Vascular Surgery, Catholic Institute of Lille, Lille, France
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23
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Sheppard R, Eisenberg MJ, Donath D, Meerkin D. Intracoronary brachytherapy for the prevention of restenosis after percutaneous coronary revascularization. Am Heart J 2004; 146:775-86. [PMID: 14597925 DOI: 10.1016/s0002-8703(03)00389-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE The purpose of this article is to review the current literature pertaining to intracoronary brachytherapy for the prevention of restenosis after percutaneous coronary revascularization (PCR). METHODS English-language articles were identified through a MEDLINE search (January 1984 to January 2003) using the keywords brachytherapy, radioactive stents, and coronary arteries. In addition, pertinent reference citations from relevant articles were reviewed. RESULTS Restenosis after PCR is a complex process, thought to be due to a combination of vessel wall remodeling and neointimal proliferation. To date, catheter-based delivery of intracoronary brachytherapy has been found to prevent vessel wall remodeling and causes a reduction in the proliferation of the neointima. Neointimal proliferation, as measured by mean neointimal area, was reduced in all animal studies (range 26%-91%). In contrast, animal studies examining radioactive stents demonstrated an increase in neointimal proliferation, suggesting that they may not be helpful at preventing post-PCR restenosis. All human studies using catheter-based intracoronary brachytherapy for in-stent restenosis have employed either beta (beta) or gamma (gamma) radiation sources with variable doses of radiation (range 7-56 Grays [Gy]). Restenosis occurred in 12% to 40% of patients in nonrandomized studies, and clinical events occurred in 13% to 50% of patients. To date, there have been 7 published randomized trials in humans comparing catheter-based intracoronary brachytherapy to placebo, with a total of 1047 patients. The dose of radiation in the trials ranged from 14 Gy to 30 Gy. During follow-up, 8% to 33% of patients who received brachytherapy had restenosis versus 39% to 64% of patients receiving placebo. Clinical events occurred in 19% to 50% among patients who received brachytherapy versus 29% to 79% among patients receiving placebo. The majority of human studies examining radioactive stents do not demonstrate a reduction in restenosis in patients post-PCR. There are no randomized trials examining radioactive stents in humans. CONCLUSION Nonrandomized studies of radioactive stents suggest they are not effective at preventing in-stent restenosis. In contrast, data from animal and human studies suggest that catheter-based intracoronary brachytherapy can prevent in-stent restenosis and reduce clinical events post-PCR.
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Affiliation(s)
- Richard Sheppard
- Division of Cardiology, Royal Victoria Hospital, Montreal, Quebec, Canada
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Pręgowski J, Bulski W, Kalińczuk Ł, Kruk M, Witkowski A. Zależność efektu brachyterapii wewnątrznaczyniowej od wielkości dawki. Rep Pract Oncol Radiother 2004. [DOI: 10.1016/s1507-1367(04)71040-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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25
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Ducasse E, Cosset JM, Eschwege F, Mazurier J, Creusy C, Chevalier J, Puppinck P, Lartigau E. [External ionizing radiation on the prosthesis-arterial anastomosis for the prevention of intimal hyperplasia and study of biomechanical resistance. Experiments and results]. ACTA ACUST UNITED AC 2003; 128:603-9. [PMID: 14659614 DOI: 10.1016/j.anchir.2003.10.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
PURPOSE To evaluate the use of external ionizing radiation for the prevention of intimal hyperplasia in anastomosis between PTFE and artery. METHODS Bypass using a 6 mm PTFE was performed on a swine subrenal aorta with a distal conventional anastomosis (N = 35) associated (test group; N = 17) or not (control group; N = 18) with post-operative external radiation (20 Gy) on this anastomosis. At 45 days, histological studies and morphometric studies were performed on the aorta receiving the anastomosis. Two protocols were performed, the first protocol with standard analysis and the animals were randomly assigned to either group (test group; N = 11 and control group; N = 13) and the second protocol with test of extraction comparing the biomechanical resistance between the irradiated group (N = 6) and the control group (N = 5). RESULTS Twenty-one animals survived the procedure in the first protocol, 11 in the second. The endothelium was restored in either group. Histological recasting was observed in the media after radiation with fibrosis and areas of necrosis. Intimal thickness was significantly lower after irradiation in the heel (P < 0.01), the head (P < 0.01) and the suture line (P < 0.001) of the artery in the first protocol. The intimal thickness was also significantly lower in the second protocol after radiation in the heel (P < 0.05) and the head of the artery (P < 0.05). There was no difference between the two groups comparing the resistance. CONCLUSION After external irradiation, the thickness parameter of the intima decreased significantly in comparison with the control group with similar resistance. Media fibrosis and necrosis need to be confirmed by further investigation.
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Affiliation(s)
- E Ducasse
- Service de chirurgie vasculaire, hôpital Saint-Philibert, groupe hospitalier de l'institut catholique de Lille, 115, rue du Grand-But, 59462, Lomme, France.
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26
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Meyer JMA, Nowak B, Schuermann K, Buecker A, Moltzahn F, Kulisch A, Heussen N, Görgen T, Büll U, Günther RW. Inhibition of Neointimal Proliferation with188Re-labeled Self-Expanding Nitinol Stent in a Sheep Model. Radiology 2003; 229:847-54. [PMID: 14657319 DOI: 10.1148/radiol.2293020368] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To evaluate a self-expanding rhenium 188 (188Re) radiochemically labeled radioactive stent in sheep. MATERIALS AND METHODS A self-expanding nitinol stent (30 mm in length, 8 mm in diameter) coated with a functionalized polymer layer was radiolabeled with 188Re. Fifty prostheses, 25 of which were radioactive (mean radioactivity, 20 MBq +/- 3.8 [SD]) and 25 of which were nonradioactive, were implanted into the external iliac arteries of 25 sheep. Stent patency was assessed with angiography. Neointimal formation was assessed with intravascular ultrasonography and histologic examination 1 month (in all sheep) and 3 months (in 12 sheep) after implantation. The results were analyzed by using repeated-measures analysis of variance with two repeated factors and paired t tests for comparison at each measuring point. RESULTS All stents were placed successfully. Data in one animal had to be excluded from the study. After 3 months, a mean neointimal area reduction of 70 mm2 +/- 55 (SD) was observed inside the radioactive stents, and a mean lumen reduction of 126 mm2 +/- 39 was observed inside the nonradioactive control stents (P =.022). An edge effect was observed in the radioactive stents in that they showed an amount of neointimal formation at the edges that was similar to that seen in control stents. This neointimal formation accounted for the maximum lumen loss in the vascular segment with the stent. CONCLUSION As compared with a nonradioactive stent, a beta particle-emitting stent, through endovascular irradiation, significantly inhibits neointimal formation inside the stent but not at the stent edges.
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Affiliation(s)
- Julius M A Meyer
- Department of Diagnostic Radiology, University of Technology, Pauwelsstrasse 30, Aachen D-52074, Germany
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Maeng M, Busk M, Tanderup K, Mertz H, Andersen HR, Thuesen L. Catheter-based 32P beta-radiation after stent implantation in porcine coronary arteries: role of source-centering and geographical miss. Catheter Cardiovasc Interv 2003; 60:247-57. [PMID: 14517934 DOI: 10.1002/ccd.10608] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The present study examined the role of source-centering and geographical miss in vascular brachytherapy. After implantation of 13 mm long stents, 38 coronary arteries in 13 pigs were randomly assigned to centered brachytherapy (n = 13), eccentric brachytherapy (n = 13), or no radiation (n = 12). Geographical miss was avoided by careful placement of a 27 mm (32)P beta-radiation source. Restenosis was quantified by angiography, histomorphometry, and intravascular ultrasound at 28 days. Source-centering led to a significant (P < 0.001) reduction of in-stent area stenosis (centered radiation, 12% +/- 5%; eccentric radiation, 37% +/- 21%; control arteries, 41% +/- 13%). Despite 7 mm coverage of the edge segments, radiation was found to induce edge stenosis due to neointima formation and constrictive vascular remodeling. We conclude that centered radiation was superior to eccentric radiation in reducing in-stent luminal narrowing while radiation-induced edge stenosis was still observed despite extension of the radiation zone to 7 mm beyond the stent edges.
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Affiliation(s)
- Michael Maeng
- Department of Cardiology, Aarhus (Skejby) University Hospital, Aarhus, Denmark.
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Jeong JM, Chung JK. Therapy with 188Re-Labeled Radiopharmaceuticals: An Overview of Promising Results from Initial Clinical Trials. Cancer Biother Radiopharm 2003; 18:707-17. [PMID: 14629819 DOI: 10.1089/108497803770418256] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The development of an in-house 188W/188Re-generator has greatly increased the use of 188Re for treating various diseases. 188Re is of widespread interest due to its attractive physical and chemical properties. Many new radiopharmaceuticals labeled with 188Re have been developed and are currently in clinical trials, such as: 188Re-labeled renal excreting agents like 188Re-mercaptoacetylglycylglycylglycine (MAG3) and 188Re-diethylenetriamine pentaacetic acid (DTPA) for prevention of coronary arterial restenosis; 188Re-labeled phosphonates such as 188Re-hydroxyethylidene diphosphonate (HEDP), 188Re-alendronate (ABP), and 188Re-ethylenediamine-N,N,N',N'-tetrakis(methylene phosphoric) acid (EDTMP) for palliation of metastatic bone pain; 188Re-labeled lipiodol such as 188Re-n-hexyldiaminedithiol (HDD)-lipiodol for treatment of liver cancer; and 188Re-labeled colloids and microspheres for treatment of diseases such as rheumatoid arthritis, peritoneal effusion, and other solid tumors. However, there is still a need to develop new 188Re-labeled radiopharmaceuticals that are more specific for target lesions such as cancer-specific monoclonal antibodies and peptides. The availability of 188Re from a generator at a reasonable cost may help increase not only the research activities but also the clinical applications of 188Re-labeled radiopharmaceuticals.
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Affiliation(s)
- Jae Min Jeong
- Department of Nuclear Medicine, Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea
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Affiliation(s)
- Ron Waksman
- Division of Cardiology, Washington Hospital Center, 100 Irving St, NW, Suite 4B-1, Washington, DC 20010, USA.
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Abstract
Restenosis is a major limitation of coronary angioplasty, requiring further intervention in the majority of cases. Intracoronary radiation has been employed in recent years to prevent restenosis lesions with effective results, principally in in-stent restenosis. Restenosis is generally considered as an excessive form of normal wound healing divided up in processes: elastic recoil, neointimal hyperplasia, and negative vascular remodeling. Restenosis has previously been regarded as a proliferative process in which neointimal thickening, mediated by a cascade of inflammatory mediators and other factors, is the key factor. Data from recent studies have pointed to negative vascular remodeling as a major contributing factor. Recent studies have also identified particular cell lines that might be critical regulators of restenosis, particularly monocyte-derived macrophages and myofibroblasts. This review summarizes the current theories of vascular biology pertaining to restenosis in coronary arteries and the potential mechanisms of why radiation may effectively inhibit restenosis.
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Affiliation(s)
- Smith Apisarnthanarax
- Department of Radiation Oncology, Rhode Island Hospital, Brown Medical School, Providence, Rhode Island 02903, USA
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Lowe HC, Mino M, Mark EJ, Mac Neill BD, Palacios IF, Houser SL. Histopathology of coronary in-stent restenosis following gamma brachytherapy. Heart 2003; 89:11-3. [PMID: 12482781 PMCID: PMC1767489 DOI: 10.1136/heart.89.1.11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The histopathology of in-stent restenosis (ISR) following gamma brachytherapy is described. Such histology has not been reported previously. An 82 year old man presented with recurrent ISR three months after gamma brachytherapy to an area of ISR within a native circumflex vessel. The recurrent ISR was treated with directional coronary atherectomy; the histopathology of this directional coronary atherectomy specimen is discussed. These histopathological examinations showed abundant extracellular matrix material. Surprisingly, there was a relatively small cellular (myofibroblastic) component, with an absence of endothelial cells and little evidence of active proliferation. ISR after gamma brachytherapy may be a pathologically distinct entity.
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Affiliation(s)
- H C Lowe
- Division of Cardiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02144-2696, USA
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Chua DCY, Almeda FQ, Senter S, Haynie J, Nguyen C, Chu JCH, Kavinsky CJ, Snell RJ, Schaer GL. Predictors of late cardiac events following treatment with Sr-90 beta-irradiation for instent restenosis. CARDIOVASCULAR RADIATION MEDICINE 2003; 4:7-11. [PMID: 12892766 DOI: 10.1016/s1522-1865(03)00117-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Intracoronary radiation therapy (IRT) with Sr-90 using the Novoste Beta-Cath system has been shown to be an effective therapy for instent restenosis (ISR), but the temporal occurrence of cardiac events and the predictors of late complications require further investigation. METHODS We analyzed the demographics, lesion characteristics and clinical outcomes of 138 consecutive patients with ISR treated with IRT from September 1998 to March 2002. Major adverse cardiac events (MACE) were defined as death, myocardial infarction (MI) or target vessel revascularization (TVR). Characteristics of early (< or =8 months) and late (>8 months) failures were analyzed. RESULTS Thirty-two (23.1%) of 138 patients had MACE on follow-up; 25% (8/32) of failures occurred late after treatment with IRT. A comparison of the clinical and angiographic profile of early and late failures using univariate analysis indicates no correlations to late failure following IRT. Duration to failure after IRT was 14.25+/-3.69 months in the late group compared to 4.63+/-2.86 months in the early group (P<.001). CONCLUSIONS Late MACE after IRT with Sr-90 for ISR occur beyond the traditional period for clinical restenosis in 25% of cases and are difficult to predict. Further study is warranted to identify patients at risk for the development of late complications after IRT.
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Affiliation(s)
- Dave C Y Chua
- Rush Heart Institute, Rush-Presbyterian-St. Luke's Medical Center, 1653 West Congress Parkway, Chicago, IL 60612, USA
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Lehmann J, King CR. Wire or coated balloon? Searching for an optimal source for intravascular brachytherapy with beta emitters using (32)P as an example. J Appl Clin Med Phys 2003; 4:58-65. [PMID: 12540819 PMCID: PMC5724438 DOI: 10.1120/jacmp.v4i1.2542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
This study identifies basic dosimetric differences between two designs for intravascular brachytherapy (IVBT) in current clinical practice and ongoing trials and their clinical implications within beta emitting systems using P-32 as an example. The two designs are (i) the wire-type source, where the radioactive source material is confined to a wirelike structure within the vessel lumen, and (ii) the balloon-surface source, where the radioactive source material is distributed over a surface area (balloon-wall) which is brought in close proximity with the vessel wall. Using Monte Carlo simulations with the EGS4 code, the target coverage, the influence of centering errors, and the perturbation of the dose distribution caused by metallic stents have been compared. The radial dose fall-off in the target region was found to be steeper for balloon surface systems compared with wire systems. The inner lumen wall dose for a balloon surface source was 25% higher than that for a wirelike source (2.5 mm vessel diameter). However, the comparably shallower fall-off from wire-type systems is very sensitive to centering uncertainties. A 0.5 mm displacement, for example, will cause the dose to change by a factor of 2 at the inner vessel wall and by a factor of 1.8 at the prescription point. It is shown that the interference from metallic stents is more significant for wire-type systems than it is for balloon-surface-type systems, where double the dose variation beyond the stent at the radial prescription distance may occur. Centering uncertainties dominate the dose perturbation effects for wire-type systems. Balloon-surface-type designs show a more predictable dose distribution that features, however, a higher inner vessel surface dose. Since a direct clinical comparison of systems of both types is not likely, these findings should be considered when interpreting clinical results from treatments with either type of source and, possibly, for future source design.
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Affiliation(s)
- J Lehmann
- Department of Radiation Oncology, Stanford University School of Medicine, 300 Pasteur Drive, Room A-055, Stanford, California 94305-5304, USA.
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Kelly BS, Heffelfinger SC, Whiting JF, Miller MA, Reaves A, Armstrong J, Narayana A, Roy-Chaudhury P. Aggressive venous neointimal hyperplasia in a pig model of arteriovenous graft stenosis. Kidney Int 2002; 62:2272-80. [PMID: 12427156 DOI: 10.1046/j.1523-1755.2002.00684.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Vascular access dysfunction is the most important cause of morbidity and hospitalization in the hemodialysis population in the United States at a cost of well over one billion dollars per annum. Venous neointimal hyperplasia characterized by stenosis and subsequent thrombosis, is the major cause of polytetrafluoroethylene (PTFE) dialysis graft failure. Despite the magnitude of the problem, there are currently no effective therapies for the prevention or treatment of venous neointimal hyperplasia in PTFE dialysis grafts. We believe that this is partly due to the lack of a validated large animal model of arteriovenous stenosis that could be used to test out novel interventions. METHODS Seven-centimeter PTFE loop grafts were placed between the femoral artery and vein of domestic pigs. The grafts were removed at 2, 4, 7, 14 and 28 days after surgery and subjected to a detailed histological and immunohistochemical examination. RESULTS Significant neointimal hyperplasia and venous stenosis developed by 28 days at the graft-vein anastomosis. There was minimal neointimal hyperplasia at the graft-artery anastomosis. Venous neointimal hyperplasia (VNH) was characterized by (a) the presence of smooth muscle cells/myofibroblasts; (b) angiogenesis within both the neointima and adventitia; and (c) the presence of an active macrophage cell layer lining the PTFE graft material. These results are very similar to the human lesion previously described by us in dialysis patients. CONCLUSIONS We have developed and validated a pig model of venous neointimal hyperplasia that is very similar to the human lesion. We believe that this is an ideal model in which to test out novel interventions for the prevention and treatment of clinical hemodialysis vascular access dysfunction.
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Affiliation(s)
- Burnett S Kelly
- Department of Surgery, University of Cincinnati, Cincinnati, Ohio 45267, USA
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35
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Soni AB, Illig KA, Sternbach Y, Anthony P, Jacob P, Reddy G, Storey J, Gerety R, Williams JP, Schell M, Waldman D, Rubin P, Green R, Okunieff P. Benefits of external beam irradiation for peripheral arterial bypass: preliminary report on a phase I study. Int J Radiat Oncol Biol Phys 2002; 54:1174-9. [PMID: 12419446 DOI: 10.1016/s0360-3016(02)03047-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE To perform a Phase I study to determine the safety and feasibility of using external beam radiotherapy to prevent neointimal hyperplasia in patients after surgical bypass of occluded infrainguinal arteries. METHODS AND MATERIALS All patients undergoing operative infrainguinal bypass for chronic ischemia were eligible for enrollment, although those requiring a prosthetic graft were preferentially considered. Immediately after bypass, the distal anastomosis was marked with clips, and the baseline anatomy of the anastomosis was documented with an intraoperative angiogram. The distal anastomotic site and 2 cm of surrounding tissues were irradiated to a total dose of 30 Gy, delivered in 10 fractions. The first dose was given within 48 h of surgery. RESULTS Twenty-one patients were enrolled in this study. No anastomotic or wound problems or any other short-term complications of the treatment developed. However, at a mean follow-up of 10 months (range 3-18), 12 (57%) of the 21 grafts had occluded. Angiography was performed in 2 patients after successful thrombolysis and demonstrated normal anastomoses without residual stenosis. Evidence of stenosis at the irradiated anastomosis was seen in only 1 of the 21 patients by ongoing ultrasound surveillance. CONCLUSION Fractionated external irradiation to a total dose of 30 Gy delivered to the distal surgical anastomosis immediately after operative bypass has no short-term complications and was associated with an apparently low rate of intimal hyperplasia. However, any possible gains made by reducing the neointimal hyperplasia at the site of anastomosis were significantly diminished by the high frequency of thrombotic events.
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Affiliation(s)
- Arvind B Soni
- Department of Radiation Oncology, University of Rochester Medical Center, 601 ElmwoodAvenue, Rochester, NY 14642, USA
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Morino Y, Kaneda H, Fox T, Takagi A, Hassan AHM, Bonan R, Crocker I, Lansky AJ, Laskey WK, Suntharalingam M, Bonneau HN, Yock PG, Honda Y, Fitzgerald PJ. Delivered dose and vascular response after beta-radiation for in-stent restenosis: retrospective dosimetry and volumetric intravascular ultrasound analysis. Circulation 2002; 106:2334-9. [PMID: 12403663 DOI: 10.1161/01.cir.0000036367.17043.03] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Observations from previous intracoronary radiation therapy trials noted a considerable discrepancy between the prescribed radiation dose and the dose actually delivered. The aims of this study were to investigate the effect of actual delivered dose on vascular changes and to test the appropriateness of the current dose prescription. METHODS AND RESULTS Serial volumetric intravascular ultrasound (IVUS) analysis was performed in 30 in-stent restenosis cases treated with a 40-mm (90)Sr/Y source train. The fixed dose was prescribed at 2 mm from the centerline of the source train (18.4 Gy at 2 mm for reference diameter < or =3.35 mm and 23 Gy for diameter > or =3.36 mm). Only stent segments with full radiation coverage and device injury were enrolled and divided into 2-mm-long subsegments (n=202). D(S90)EEM (the minimum dose absorbed by 90% of the external elastic membrane surface) was calculated as the delivered dose corresponding to each segment, assuming that the radiation catheter occupied the same position in the vessel as the IVUS catheter. Mean D(S90)EEM of 23.5+/-5.82 Gy (range 12.3 to 41.7 Gy) was delivered to these subsegments. Overall, intimal hyperplasia volume remained constant from postintervention to follow-up (2.23+/-1.10 to 2.32+/-1.09 mm3/m; P=NS). Regression analysis revealed there was no correlation between delivered dose intensity and changes in intimal hyperplasia volume. No particular dose-dependent complications were appreciated in this delivered dose range. CONCLUSIONS The current dose-prescription protocol of (90)Sr/Y radiation to native in-stent restenosis lesions may provide substantial inhibition of neointimal reproliferation regardless of the actual delivered dose intensity.
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Affiliation(s)
- Yoshihiro Morino
- Center for Research in Cardiovascular Interventions, Stanford University Medical Center, Stanford, Calif 94305-5637, USA
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37
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Chan RC, Fournadjiev J, Yazdi HA, Kim HS, Cheneau E, Yang N, O' Tio F, Ilzycer D, Kichel D, Seabron R, Waksman R. Effectiveness of radioactive tungsten source in the prevention of restenosis in stented porcine coronary arteries. Int J Radiat Oncol Biol Phys 2002; 54:252-62. [PMID: 12182999 DOI: 10.1016/s0360-3016(02)02927-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
PURPOSE Intracoronary radiation has shown the potential to inhibit neointimal proliferation in porcine models of restenosis. The objective of this study was to determine whether intracoronary radiation using a new coiled wire of tungsten-188 ((188)W), a pure beta emitter (half-life 69.4 days) is safe. In addition, a dose of 0 Gy, 18 Gy, or 25 Gy prescribed to 2 mm from the center of the source and delivered intraluminally is sufficient to prevent restenosis and free from adverse effects. METHODS AND MATERIALS Ten domestic swine underwent 13-mm stent implantation (SI) into two arteries, left anterior descending plus either the left circumflex or right coronary artery. After SI, a closed-end lumen radiation catheter was inserted to the treated artery and a 40-mm coiled (188)W source was manually delivered to cover the stented segment and its margins. A total of 20 arteries were randomized to treatment with a radiation dose of 0, 18 Gy, or 25 Gy delivered to 2 mm depth from the center of the source. Four weeks after the procedure, the swine underwent angiography and intravascular ultrasound using automated pullback at 0.5 mm/s. before being killed and the arteries perfusion fixed. Histopathologic and histomorphometric analyses were performed at 28 days after injury and radiation. RESULTS Irradiation with (188)W at a dose of 25 Gy after SI significantly inhibited neointima formation (intimal area: 1.05 +/- 0.64 vs. 2.75 +/- 0.99 mm(2), p < 0.01) and at an 18 Gy dose of radiation (intimal area: 1.73 +/- 0.49 vs. 2.75 +/- 0.99 mm(2)), as compared to controls. One artery receiving 18 Gy and two arteries receiving 25 Gy were totally occluded at follow-up due to thrombus formation but no edge stenosis was observed in any of the irradiated arteries. CONCLUSIONS Intracoronary radiation therapy using a new coiled wire of (188)W source delivered after SI appeared to be safe and well tolerated. The radiation doses demonstrated efficacy in reducing neointima formation in the porcine coronary stent injury model.
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Affiliation(s)
- Rosanna C Chan
- Department of Radiation Oncology, Washington Hospital Center, 110 Irving Street NW, Washington, DC 20010, USA
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Apple M, Waksman R, Chan RC, Vodovotz Y, Fournadjiev J, Bass BG. Radioactive 133-Xenon gas-filled balloon to prevent restenosis: dosimetry, efficacy, and safety considerations. Circulation 2002; 106:725-9. [PMID: 12163434 DOI: 10.1161/01.cir.0000023945.21317.27] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Ionizing radiation administered intraluminally via catheter-based systems using solid beta and gamma sources or liquid-filled balloons has shown reduction in the neointima formation after injury in the porcine model. We propose a novel system that uses a 133-Xenon (133Xe) radioactive gas-filled balloon catheter system. METHODS AND RESULTS Overstretch balloon injury was performed in the coronary arteries of 33 domestic pigs. A novel 133Xe radioactive gas-filled balloon (3.5/45 mm) was positioned to overlap the injured segment with margins. After vacuum was obtained in the balloon catheter, approximately 2.5 cc of 133Xe gas was injected to fill the balloon. Doses of 0, 7.5, 15, and 30 Gy were delivered to a distance of 0.25 mm from the balloon surface. The dwell time ranged from 1.0 to 4.0 minutes, depending on the dose. Localization of 133Xe in the balloon was verified by a gamma camera. The average activity in a 3.5/45-mm balloon was measured at 67.7+/-12.1 mCi, and the total diffusion loss of the injected dose was 0.26% per minute of the injected dose. Bedside radiation exposure measured between 2 and 6 mR/h, and the shallow dose equivalent was calculated as 0.037 mrem per treatment. Histomorphometric analysis at 2 weeks showed inhibition of the intimal area (intimal area corrected for medial fracture length [IA/FL]) in the irradiated segments of 0.26+/-0.08 with 30 Gy, 0.07+/-0.24 with 15 Gy, and 0.12+/-0.89 with 7.5 Gy versus 0.76+/-0.08 with control P<0.001. CONCLUSIONS 133Xe gas-filled balloon is feasible and effective in the reduction of neointima formation in the porcine model and safe for use in coronary arteries.
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Affiliation(s)
- Marc Apple
- Parkview Radiation Oncology Center, Fort Wayne, Ind, USA
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Abstract
Coronary artery disease is the leading cause of mortality in the West with over 1.2 million angioplasties performed annually. Despite the introduction of stents, restenosis occurs in 30-40% of vessels, which until recently has only been treated effectively by coronary artery bypass surgery. Coronary artery brachytherapy appears to provide an alternative, less invasive remedy. The mechanisms of restenosis and how these are inhibited by radiation are described here. The practicalities of radiation delivery and the history of the development of intravascular radiation as an effective clinical tool are outlined. Finally, the pitfalls of the current technology and the areas in which future research must be targeted for the field to develop are discussed.
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Affiliation(s)
- E C Sims
- Department of Cardiac, Vascular and Inflammation Research, Bart's and The London, Queen Mary's School of Medicine and Dentistry, UK
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Sianos G, Wijns W, de Feyter PJ, van Domburg R, Serruys PW. Geographical miss and restenosis during catheter-based intracoronary beta-radiation for de novo lesions. CARDIOVASCULAR RADIATION MEDICINE 2002; 3:138-46. [PMID: 12974364 DOI: 10.1016/s1522-1865(03)00101-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVES We sought to determine the impact of geographical miss (GM) on restenosis rates after intracoronary beta-radiation therapy for de novo lesions. BACKGROUND GM is the situation in which injured vessel segments (VSs) are receiving low-dose radiation and is accounted for edge restenosis. Its impact on the overall restenosis rates remains to be determined. METHODS We analyzed 330 patients (356 vessels) treated according to the Beta Radiation in Europe (BRIE) and the Dose Finding study protocols. Using quantitative coronary angiography (QCA), the effective irradiated segment (EIRS), its edges and the total VS were analysed. The edges of the EIRS that were injured constituted the GM edges. Restenosis was defined as diameter stenosis > 50% at follow-up. GM was determined by the simultaneous electrocardiographic-matched, side-by-side projection of the source and balloons deflated and surrounded by contrast, at the site of injury, in identical angiographic projections. RESULTS In 20.5% of the vessels, GM was non-interpretable due to inadequate filming. GM occurred at 30.4% of the interpretable edges and 53% of the interpretable vessels that were analysed. Edge restenosis was significantly increased in the GM compared to non-GM edges (13.16% vs. 4.17%, respectively, P = .001), both in the proximal (P = .03) and the distal (P = .001) edges. GM associated with stent injury significantly increased edge restenosis (P = .006). GM related to balloon injury tended to be associated with increment in edge restenosis (P = .07). The restenosis in the EIRS was similar between vessels with and without GM (17.78% and 14.85%, respectively, P = .6). GM was associated with significant increment in the restenosis at the analyzed VS (31.85% vs. 21.48%, P = .05). CONCLUSIONS GM is strongly associated with edges and restenosis in the analysed VS. GM does not increase restenosis in the EIRS.
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Affiliation(s)
- Georgios Sianos
- Department of Interventional Cardiology, Erasmus MC Rotterdam, Thoraxcenter Bd 404, Dr Molewaterplein 40, 3015 GD Rotterdam, The Netherlands
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Kepka C, Pszona S, Bulski W, Witkowski A. The "shielding" effect of the guide wire during coronary brachytherapy with P-32 source. CARDIOVASCULAR RADIATION MEDICINE 2002; 3:205-8. [PMID: 12974375 DOI: 10.1016/s1522-1865(03)00099-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Intracoronary beta irradiation (use of beta radiation for intracoronary irradiation) is an effective method in reducing neointimal proliferation after successful angioplasty and stent implantation. However, long-term results may be influenced by absolute dose and by the homogeneity in dose distribution. In our study, we investigated dose perturbation due to the presence of a conventional guide wire during irradiation. The Galileo III centering catheter and P-32 beta source were used. The 55 MD GAF Chromic foil was positioned within a phantom made of PMMA. The dose distribution at cylindrical surfaces has been assessed using GAF Chromic dosimetric foil MD55 (Nuclear Associates, USA). Our study demonstrated the significant dose reduction of 46% in the most "shaded" area. The dose reduction to 80% or less occupy the 60 degrees sector. This phenomenon can cause progression of late restenosis. In conclusion, the results suggest that technical improvements in centering catheter construction should be made to eliminate the "shielding" effect of the guide wire.
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Affiliation(s)
- Cezary Kepka
- Haemodynamical Department, Institute of Cardiology, Alpejska 42, 04-628 Warsaw, Poland.
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Maehara A, Patel NS, Harrison LB, Weissman NJ, Bui AB, Kim HS, Ajani AE, Castagna MT, McMillan TL, Yang N, Chan R, Pisch J, Quan H, Chiu-Tsao ST, Waksman R, Mintz GS. Dose heterogeneity may not affect the neointimal proliferation after gamma radiation for in-stent restenosis: a volumetric intravascular ultrasound dosimetric study. J Am Coll Cardiol 2002; 39:1937-42. [PMID: 12084591 DOI: 10.1016/s0735-1097(02)01880-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
OBJECTIVES The goal of this study was to use serial (postirradiation and follow-up) volumetric intravascular ultrasound (IVUS): 1) to evaluate the actual distribution of gamma radiation in human in-stent restenosis (ISR) lesions, and 2) to analyze the relationship between neointimal regrowth and the delivered radiation dose. BACKGROUND The relationship between the neointimal regrowth and delivered dose during the treatment of ISR remains unknown. METHODS We analyzed 20 actively (gamma emitter) treated, native artery ISR patients from the Washington Radiation for In-Stent restenosis Trial (WRIST) that met the following criteria: on both postirradiation and six-month follow-up IVUS imaging, > or =80% of the external elastic membrane circumference could be identified throughout the treated length including the lesion and proximal and distal reference segments. Intravascular ultrasound images were digitized every 1 mm. Proximal and distal reference and stented segment luminal and adventitial contours were imported and reconstructed. The source was placed circumferentially at the site of the IVUS catheter and longitudinally according to the relationship between the radioactive seeds and stent edges. Using Monte Carlo simulations, dose volume histograms for the adventitia and intima were calculated. The relationship between the neointimal regrowth and calculated doses were evaluated. RESULTS There was large dose heterogeneity at both the intimal and adventitial levels. Most of the sites (93%) received >4 Gy at the adventitia, and all of the sites received >4 Gy at the intima. There was no relationship between neointimal regrowth and radiation dose. CONCLUSIONS Although there may be large dose heterogeneity, gamma irradiation (using a fixed dose prescription) appears to deliver a sufficient dose to prevent neointimal regrowth.
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Affiliation(s)
- Akiko Maehara
- Cardiovascular Research Institute, Washington Hospital Center, Washington DC 20010, USA
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Flickinger JC, Kondziolka D, Maitz AH, Lunsford LD. An analysis of the dose-response for arteriovenous malformation radiosurgery and other factors affecting obliteration. Radiother Oncol 2002; 63:347-54. [PMID: 12142099 DOI: 10.1016/s0167-8140(02)00103-2] [Citation(s) in RCA: 200] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
PURPOSE The aim of this study was to better understand arteriovenous malformation (AVM) obliteration rates after radiosurgery. METHODS AND MATERIALS We studied obliteration after Gamma knife radiosurgery in 351 AVM patients with 3-11 years of follow-up imaging. The median marginal dose was 20 Gy (range: 12-30) and median treatment volume was 5.7 cm(3) (range: 0.26-24). Stereotactic targeting was with angiography alone in 250 AVMs, and additional magnetic resonance (MR) imaging in 101 AVMs. RESULTS We documented obliteration by angiography in 193/264 (73%) AVM, and by MR alone in 75/87 (86%) AVM for a 75% corrected obliteration rate. We identified persistent out-of-field nidus in 18% of embolized vs. 5% of non-embolized patients, (P = 0.006). Multivariate analysis correlated in-field obliteration with marginal dose (P < 0.0001) and sex (P < or = 0.026, but not for overall obliteration P = 0.19). A mathematical dose-response model for overall obliteration was constructed to generate a dose-response curve for AVM obliteration with a maximum overall obliteration rate of 88% and minimal improvement above 25 Gy. We could not define the value of alpha/beta for AVM obliteration to a level of statistical significance. CONCLUSION The rate of AVM obliteration from radiosurgery depends on the marginal dose administered with a dose-response curve that reaches a maximum of approximately 88%. The dose-response plateau reflects problems with target definition which is made more difficult by prior embolization.
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Affiliation(s)
- John C Flickinger
- Department of Radiation Oncology, Center for Image-Guided Neurosurgery, University of Pittsburgh School of Medicine, B-300, 200 Lothrop Street, Pittsburgh, PA 15213, USA
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Coen VLMA, Marijnissen JPA, Ligthart JMR, de Pan C, Drenth J, den Boer A, van der Giessen WJ, Serruys PW, Levendag PC. Inaccuracy in manual multisegmental irradiation in coronary arteries. Radiother Oncol 2002; 63:89-95. [PMID: 12065108 DOI: 10.1016/s0167-8140(02)00020-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Retrospective evaluation of the accuracy of manual multisegmental irradiation with a source train for irradiation of long (re)stenotic lesions in coronary arteries, following percutaneous transluminal coronary angioplasty (PTCA). MATERIAL AND METHODS Thirty-six patients were treated with intracoronary irradiation following PTCA with manual multisegmental irradiation. These patients were included in the multicenter, multinational 'European Surveillance Registry with the Novoste Beta-Cath system' (RENO). In all 36 patients the target length (i.e. PTCA length plus 5-mm margin at each side) was too long for the available source train lengths (30 and 40 mm). In 33 patients the radiation delivery catheter was manually positioned twice and in three patients three times in series, trying to avoid any gap or overlap. The total number of junctions was 39. Following a successful PTCA procedure the site of angioplasty was irradiated using the Novoste Beta-Cath afterloader with a 5-F non-centered catheter which accommodates the sealed beta-emitting (90)Sr/(90)Y source train or dummy source train. Radiation was delivered first to the distal part of the target length. Fluoroscopic images of this source position were stored in the computer memory. For irradiation of the proximal part of the target length, the delivery catheter had to be retracted over a distance equal to the source length used for the distal part. This was done by a continuous overlay video loop with ECG-gated replay of the image stored in the computer memory. The dummy source was used to position the delivery catheter so that the junction between both source positions was as precise as possible. Measurements of gap or overlap between the source positions were performed retrospectively on printed images. Doses were calculated, in accordance with the Novoste study protocol, at a distance of 2 mm from the source axis (=dose prescription distance) in several points along the irradiated length. RESULTS Interventional or PTCA length varied between 33 and 95 mm. The lesion sites were in the left anterior descending artery, (n=6), right coronary artery (n=20), left circumflex artery (n=6) and one vein graft. The administered radiation dose was determined by the vessel diameter and the presence of a stent. This dose, prescribed at a distance of 2 mm from the source axis, varied between 16 and 22 Gy. No gap or overlap was seen between the two source trains in only two out of 39 cases. In 16 cases there was a gap ranging between 0.6 and 9.6 mm and 18 cases showed an overlap of 0.5-14.4 mm. In three patients the measurement was not possible. In case of a gap the minimal dose calculated at 2 mm from the source axis varies between 0 and 87% of the prescribed dose, depending on the distance between both sources. In case of overlap the maximal dose varies between 110 and 200% of the prescribed dose at 2 mm from the source axis. CONCLUSIONS The results show the inaccuracy of manual multisegmental irradiation using a source train in coronary arteries, causing unacceptable dose inhomogeneities at a distance of 2 mm from the source axis at the junction between both source positions. Moreover, a perfect junction will never be possible due to movement of the non-centered radiation delivery catheter in the vessel lumen, as applied in this study. Manual multisegmental irradiation is therefore not recommended. Using longer line sources or source trains or preferably an automated stepping source is a more reliable and safer technique for treatment of long lesions.
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Affiliation(s)
- Veronique L M A Coen
- Department of Radiotherapy, Daniel den Hoed Cancer Center, University Hospital Rotterdam, Groene Hilledijk 301, Rotterdam, The Netherlands
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45
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Abstract
This is a review of the relatively recently developed field of intravascular brachytherapy of coronary arteries. It presents a brief overview of the discipline of coronary angioplasty describing the problem of restenosis and discusses the potential for ionizing radiation to overcome this problem. It examines the various methods that have been used to irradiate the coronary arteries comparing their advantages and disadvantages. Special consideration is given to seeds and wires in the artery, radioactive liquids in the angioplasty balloon and radioactive stents. Passing reference is made to a number of other methods that have also been proposed, but which are not commonly used to irradiate the coronary arteries at present. The dosimetry of each of the major techniques is discussed and the data from different laboratories compared. Specific consideration is given to the need for centring of the radioactive source and the factors affecting the selection of a dose prescription. A brief review of recent clinical trials is followed by an examination of possible future directions in this field including the use of intravascular ultrasound to improve dosimetry, the use of gas-filled balloons to enhance the penetration of beta-emitting sources and the use of gamma-emitting stents to overcome the problems associated with edge restenosis.
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Affiliation(s)
- R A Fox
- Department of Medical Physics, Royal Perth Hospital, Australia.
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46
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Abstract
In-stent restenosis (ISR) is a novel pathobiologic process, histologically distinct from restenosis after balloon angioplasty and comprised largely of neointima formation. As percutaneous coronary intervention increasingly involves the use of stents, ISR is also becoming correspondingly more frequent. In this review, we examine the available studies of the histology and pathogenesis of ISR, with particular reference to porcine and other animal models. An overview of mechanical treatments is then provided, which includes PTCA, directional coronary atherectomy and high speed rotational atherectomy. Radiation-based therapies are discussed, including a summary of current problems associated with this modality of treatment. Finally, novel strategies for the prevention of ISR are addressed, including novel developments in stents and stent coatings, conventional drugs, nucleic acid-based drugs and gene transfer. Until recently, limited pharmacologic and mechanical treatment options have been available for both treatment and prevention of ISR. However, recent advances in gene modification and gene transfer therapies and, more particularly, in local stent-based drug delivery systems make it conceivable that the incidence of ISR will now be seriously challenged.
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Affiliation(s)
- Harry C Lowe
- Cardiology Division, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
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47
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Hansrani M, Overbeck K, Smout J, Stansby G. Intravascular brachytherapy for peripheral vascular disease. Cochrane Database Syst Rev 2002:CD003504. [PMID: 12519600 DOI: 10.1002/14651858.cd003504] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND International treatment of atherosclerotic narrowed and blocked arteries involves either bypassing the blockage using a graft, widening it from the inside with a balloon, a procedure known as percutaneous transluminal angioplasty (PTA), or providing a strut to hold the vessel open, known as a stent. All of these treatments are however limited by the high numbers that fail within a year. Intravascular brachytherapy (IVBT) is the application of radiation directly to the site of vessel narrowing. It is known to inhibit the processes that lead to restenosis (narrowing) of vessels and grafts after treatment. OBJECTIVES The objective of this review was to assess the efficacy and complications of intravascular brachytherapy on maintaining patency after angioplasty or stent insertion in native vessels or bypass grafts of the iliac or infrainguinal arteries. SEARCH STRATEGY The reviewers searched the Cochrane Peripheral Vascular Diseases Group Trials Register (last searched 5 July 2002), the Cochrane Controlled Trials Register (last searched Issue 2, 2002), MEDLINE, EMBASE and reference lists of relevant articles. SELECTION CRITERIA Randomised trials of the use of brachytherapy as an adjunct to the treatment of patients with peripheral arterial diseases (PAD) or stenosed bypass grafts of the iliac or infrainguinal arteries arteries versus the procedure without brachytherapy. DATA COLLECTION AND ANALYSIS Two reviewers independently assessed trial quality and extracted data. Adverse events information was collected from the trials. MAIN RESULTS One trial was identified which met the inclusion criteria, involving 117 patients, mean age 71 years (43-89). The trial compared PTA versus PTA and IVBT in patients with long-segment de novo or restenotic lesions or occlusions of any length in the femoropopliteal artery. Results were provided at six month follow up in 107 patients (54 PTA alone, 53 PTA+IVBT). The results favoured adjuvant IVBT in preventing restenosis/occlusion with an odds ratio (OR) of 0.35 (95% CI 0.24 to 0.53). Analysis of subgroups showed a significant benefit of IVBT in non-diabetics, OR 0.22 (95% CI 0.07 to 0.69), in those undergoing IVBT in restenotic lesions, OR 0.32 (95% CI 0.10 to 1.01), occlusive lesions, OR 0.19 (95% CI 0.06 to 0.62) and lesions in which the PTA length was greater than 10cm, OR 0.24 (95% CI 0.09 to 0.62). REVIEWER'S CONCLUSIONS Results from the only trial available would suggest that IVBT is effective at improving the patency of femoropopliteal arteries undergoing PTA in the short-term, particularly in non-diabetics with long occlusions (>10cm).
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Affiliation(s)
- M Hansrani
- Department of Surgery, University of Newcastle upon Tyne, Department of Surgery, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne, UK, NE24HH
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48
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Kałuza GL, Jenkins TP, Mourtada FA, Ali NM, Lee DP, Okura H, Fitzgerald PJ, Raizner AE. Targeting the adventitia with intracoronary beta-radiation: comparison of two dose prescriptions and the role of centering coronary arteries. Int J Radiat Oncol Biol Phys 2002; 52:184-91. [PMID: 11777637 DOI: 10.1016/s0360-3016(01)01806-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE To compare by intravascular ultrasound (IVUS) the efficacy of delivering the prescribed dose to the adventitia between two commonly used dose prescriptions for intracoronary radiotherapy. METHODS AND MATERIALS In 59 human postangioplasty coronary vessels, one IVUS cross-section (1 mm thick) with the highest plaque burden was used for creating dose-volume histograms with different hypothetical positions of the source. RESULTS On average, prescription to 1 mm beyond lumen surface resulted in delivery of the prescribed dose (20 Gy +/- 20%) to a higher fraction of adventitial volume than with the prescription to 2 mm from the source, with source placed in vessel center, lumen center, or in the IVUS catheter position. Source placement in the lumen center resulted in a low dose heterogeneity to the adventitia and the least dose heterogeneity to the intima. CONCLUSIONS Prescription to 1 mm beyond lumen surface appeared more effective in delivering the prescribed dose to the adventitia than the American Association of Physicists in Medicine (AAPM) recommended prescription to 2 mm from the source center. Moreover, centering the source in the lumen provides the better balance of effective adventitial targeting and intimal dose homogeneity. Modification of the current AAPM recommendation for dose prescription for intracoronary radiotherapy should be considered.
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Affiliation(s)
- Grzegorz L Kałuza
- Methodist DeBakey Heart Center and Baylor College of Medicine, Houston, TX 77030, USA
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49
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Teirstein PS, Kuntz RE. New frontiers in interventional cardiology: intravascular radiation to prevent restenosis. Circulation 2001; 104:2620-6. [PMID: 11714660 DOI: 10.1161/hc4601.099465] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- P S Teirstein
- Division of Cardiovascular Diseases, Scripps Clinic, La Jolla, California, USA.
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50
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van Der Giessen WJ, Regar E, Harteveld MS, Coen VL, Bhagwandien R, Au A, Levendag PC, Ligthart J, Serruys PW, den Boer A, Verdouw PD, Boersma E, Hu T, van Beusekom HM. "Edge Effect" of (32)p radioactive stents is caused by the combination of chronic stent injury and radioactive dose falloff. Circulation 2001; 104:2236-41. [PMID: 11684637 DOI: 10.1161/hc4301.097873] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Radioactive stents have been reported to reduce in-stent neointimal thickening. An unexpected increase in neointimal response was observed, however, at the stent-to-artery transitions, the so-called "edge effect." To investigate the factors involved in this edge effect, we studied stents with 1 radioactive half and 1 regular nonradioactive half, thereby creating a midstent radioactive dose-falloff zone next to a nonradioactive stent-artery transition at one side and a radioactive stent-artery transition at the other side. METHODS AND RESULTS Half-radioactive stents (n=20) and nonradioactive control stents (n=10) were implanted in the coronary arteries of Yucatan micropigs. Animals received aspirin and clopidogrel as antithrombotics. After 4 weeks, a significant midstent stenosis was observed by angiography in the half-radioactive stents. Two animals died suddenly because of coronary occlusion at this mid zone at 8 and 10 weeks. At 12-week follow-up angiography, intravascular ultrasound and histomorphometry showed a significant neointimal thickening at the midstent dose-falloff zone of the half-radioactive stents, but not at the stent-to-artery transitions at both extremities. Such a midstent response (mean angiographic late loss 1.0 mm) was not observed in the nonradioactive stents (mean loss 0.4 to 0.6 mm; P< 0.01). CONCLUSIONS The edge effect of high-dose radioactive stents in porcine coronary arteries is associated with the combination of stent injury and radioactive dose falloff.
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Affiliation(s)
- W J van Der Giessen
- Department of Cardiology, Thoraxcenter, Erasmus Medical Center, Rotterdam, the Netherlands.
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