Intravascular radiation therapy after balloon angioplasty of narrowed femoropopliteal arteries to prevent restenosis: results of the PARIS feasibility clinical trial

Treatment of Difficult, Calcified Lesions: Plaque Modification Strategies

Endovascular management of peripheral arterial disease is continually evolving. Most changes focus on addressing the challenges that hinder optimal patient outcomes; one of the most significant is how to best treat calcified lesions. Hardened plaque results in a variety of technical issues including impaired device delivery, decreased luminal revascularization, poor stent expansion, heightened risk of in-stent stenosis or thrombosis, and increased procedural time and cost. For this reason, plaque modification devices have been developed to mitigate this issue. This paper will describe these strategies and provide the reader with an overview of devices that can be used to treat chronically hardened lesions.

When Are Endovascular and Open Bypass Treatments Preferred for Femoropopliteal Occlusive Disease?

Several meta-analyses and multicenter trials have shown that chronic limb ischemia did not occur for up to 5 years in 50%–70% of patients who underwent saphenous vein grafts, with limb salvage and perioperative mortality rates of >80% and 3%, respectively. However, open surgical bypass can have limitations, including postoperative morbidity/wound complications of 10%–20% and prolonged length of hospital stay and outpatient care. Several studies have analyzed clinical outcomes for patients with critical limb ischemia treated with endovascular therapies, but they have been mainly retrospective with significant heterogeneity or were single center. Only few randomized trials have compared surgical vs. endovascular therapy. These included the Bypass vs. Angioplasty in Severe Ischemia of the Leg (BASIL) trial, with no differences found in amputation-free or overall survival rates at 1 year; however, late outcomes favored the surgical group. The Bypass or Angioplasty in Severe Intermittent Claudication (BASIC) trial concluded that the 1-year patency rates were 82% and 43% for bypass and angioplasty, respectively. The BEST Endovascular vs. Best Surgical Therapy in Patients with Critical Limb Ischemia (BEST-CLI) trial is currently enrolling patients. This review analyzed studies comparing open vs. endovascular therapy in patients with femoropopliteal disease. (This is a review article based on the invited lecture of the 45th Annual Meeting of Japanese Society for Vascular Surgery.)

Diagnosis, classification, and treatment of femoropopliteal artery in-stent restenosis

In-stent restenosis is a pervasive challenge to the durability of stenting for the treatment of lower extremity ischemia. There is considerable controversy about the criteria for diagnosis, indications for treatment, and preferred algorithm for addressing in-stent restenosis. This evidence summary seeks to review existing information on strategies for the treatment of this difficult problem.

Percutaneous Therapies for Peripheral Artery Disease

Percutaneous therapies for peripheral artery disease continue to evolve with new techniques and devices. Although guidelines-recommended therapies have impacted cardiovascular morbidity and mortality, endovascular interventions have been shown to reduce limb pain, improve quality of life, and prolong walking distance for those with claudication and to reduce amputation rates among those with critical limb ischemia. Novel devices such as drug-eluting stents and drug-coated balloons have improved patency for moderate-length lesions, whereas others allow treatment of heavily calcified and tortuous segments. New adjunctive devices to cross lesions and reduce or modify associated plaque have also been developed, although level 1 data regarding their efficacy are sparse. There has also been a better mechanistic understanding of lower extremity endovascular treatment using tools such as intravascular ultrasound. This information has highlighted the need for better stent size selection for the femoropopliteal arterial segments and larger balloon diameters for the tibial arteries. Moreover, a wound perfusion approach with direct in-line flow, the so-called angiosome approach, and reconstruction of the pedal loop have been advocated for improved wound healing. Technical advances such as the tibiopedal access and reentry methods have allowed crossing of lesions that were considered no option for the endovascular approach in the past. Collectively, there has been increased awareness, interest, and commitment by various specialty societies and organizations to advance the treatment of peripheral artery disease and critical limb ischemia. This is also evident by the recent coalition of 7 professional societies and organizations that represented >150 000 allied health professionals and millions of patients with peripheral artery disease at the 2015 Centers for Medicaid and Medicare Services Medicare Evidence Development and Coverage Analysis Committee meeting. The percutaneous therapies for peripheral artery disease continue to evolve with longer follow-up with randomized data and larger prospective registries. In the future, it is hopeful that we will treat the lower extremity arteries according to segments, taking into account plaque morphology, luminal versus subintimal crossing, location, and stenotic versus occlusive disease. Until then, we must identify the most cost-effective, efficacious, and safe treatment for each patient. The goal of this article is to aid the practicing vascular specialist consider the optimal choices for the management of patients with vascular disease.

High dose-rate brachytherapy for the treatment of lower extremity in-stent restenosis

OBJECTIVE

Historically, edge stenosis and late thrombosis limited the effectiveness of adjunctive endovascular brachytherapy (EVBT) for in-stent restenosis (ISR) after percutaneous transluminal angioplasty (PTA) and stenting. We evaluated an updated protocol of PTA and EVBT for ISR among patients with lower extremity occlusive disease.

METHODS

This is a retrospective, single-center review of patients treated with PTA and EVBT for ISR in the iliac and femoropopliteal segments between 2004 and 2012. A dose of 20 Gy was given at a depth of 0.5 mm beyond the radius of the largest PTA balloon using iridium 192, with at least 2-cm-long margins of radiation coverage proximal and distal to the injured area. Stents were assessed for patency by duplex ultrasound imaging at 1, 3, 6, 9, 12, and 18 months and then yearly. The primary end point was freedom from ≥50% restenosis in the treated segment at 6 months, 1 year, and 2 years. Patency data were estimated using the Kaplan-Meier method. Secondary end points were early and late thrombotic occlusion.

RESULTS

Among 42 consecutive cases in 35 patients of EVBT for ISR in common or external iliac (9 [20.8%]) and superficial femoral or popliteal (33 [76.7%]) arteries, or both, 21 patients (50%) had claudication, asymptomatic hemodynamically significant stenoses were identified on duplex ultrasound imaging in 16 (38.1%), and 4 (9.8%) had critical limb ischemia. Mean treated length was 23.5 ± 12.3 cm over a mean duration of 16.1 ± 9.6 minutes. There was one technical failure (2.3%). Median post-EVBT follow-up time was 682 days (range, 1-2262 days). There were two (4.9%) and five (11.9%) cases of early and late thrombotic occlusions, respectively. There was one death, believed to be secondary to acute coronary syndrome. Primary, assisted primary, and secondary patency in the entire cohort was 75.2%, 89.1%, and 89.1%, respectively, at 1 year and 63.7%, 80.6%, and 85.6%, respectively, at 2 years.

CONCLUSIONS

This contemporary protocol of PTA and adjunctive EVBT for lower extremity ISR, which is updated from those used in prior trials and includes a surveillance strategy that identifies at-risk stents for reintervention before occlusion, may be a promising treatment for lower extremity ISR at institutions where a close collaboration between vascular surgeons and radiation oncologists is feasible.

Advances in Vascular Brachytherapy over the Last 10 Years: Focus on Femoropopliteal Applications

Restenosis and the need for repeated interventions after percutaneous transluminal angioplasty (PTA) remain major drawbacks limiting a widespread application of this minimally invasive technique in the femoropopliteal segment. During the last decade, vascular brachytherapy (BT) emerged as a promising, novel technology with the potential to reduce the rates of restenosis. Meanwhile, several randomized controlled trials have suggested beneficial short and midterm effects of BT in the femoropopliteal arteries. However, despite substantial advances, many questions remain regarding the utility of vascular BT and its dissemination as a practical tool to prevent restenosis. The risk of complications, such as late stent thrombosis, edge effect, catch-up late restenosis, and potential aneurysm formation, as well as the logistical issues associated with the use of this technology in the catheterization laboratory, are delaying the acceptance of BT for routine use. This article reviews the developments of BT for restenosis prevention during the past decade, focusing on implications for peripheral endovascular treatment.

Current state of endovascular treatment of femoro-popliteal artery disease

Considerable advances have been made over the last decade in percutaneous technology for the treatment of atherosclerotic diseases in the femoro-popliteal arteries. While treatment strategies are well defined in the iliac segment, where angioplasty and stenting perform well in appropriately selected lesions, the search for a durable transcatheter therapy for femoro-popliteal lesions continues. Whereas balloon angioplasty (PTA) is the accepted therapy for short lesions, long diffuse lesions are still recommended for surgical treatment. However, attractive new technologies ranging from transcatheter plaque excision to laser ablation, rotational atherectomy, cryoplasty, brachytherapy, and placement of drug-eluting stents to simple angioplasty with drug-coated balloons may have the potential to replace femoro-popliteal bypass surgery as a treatment of choice for complex lesions. This article reviews the status of percutaneous endovascular techniques for the treatment of femoro-popliteal artery occlusive disease.

Endovascular techniques in limb salvage: cutting, cryo, brachy, and drug-eluting balloons

The complex pathophysiology response to injury of the lower-extremity arteries has prompted the development of several unique balloon technologies to overcome initial technical failures and short-term intimal hyperplasia. Cryoplasty alters the cellular and mechanical properties of the vessel wall during angioplasty. Cutting balloons incise the wall, preventing elastic recoil and allowing expansion of the lumen at a lower pressure, thus limiting barotrauma. Drug-eluting balloons actively transfer inhibitory compounds to the wall during the initial therapy, while brachytherapy balloons allow for localized delivery of radiation to inhibit the proliferative response seen after angioplasty. These platforms provide unique means to enhance immediate and short-term results and also reduce stent usage in the lower extremity.

Intravascular brachytherapy for peripheral vascular disease

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.

Internal radiotherapy techniques using radiolanthanide praseodymium-142: a review of production routes, brachytherapy, unsealed source therapy

Radionuclides of rare earth elements are gaining importance as emerging therapeutic agents in nuclear medicine. β(-)-particle emitter 142Pr [T (1/2) = 19.12 h, E(-)β = 2.162 MeV (96.3%), Eγ = 1575 keV (3.7%)] is one of the praseodymium-141 (100% abundant) radioisotopes. Production routes and therapy aspects of 142Pr will be reviewed in this paper. However, 142Pr produces via 141Pr(n, γ) 142Pr reaction by irradiation in a low-fluence reactor; 142Pr cyclotron produced, could be achievable. 142Pr due to its high β(-)-emission and low specific gamma γ-emission could not only be a therapeutic radionuclide, but also a suitable radionuclide in order for biodistribution studies. Internal radiotherapy using 142Pr can be classified into two sub-categories: (1) unsealed source therapy (UST), (2) brachytherapy. UST via 142Pr-HA and 142Pr-DTPA in order for radiosynovectomy have been proposed. In addition, 142Pr Glass seeds and 142Pr microspheres have been utilized for interstitial brachytherapy of prostate cancer and intraarterial brachytherapy of arteriovenous malformation, respectively.

Beta endovascular brachytherapy using CO2-filled centering catheter for treatment of recurrent superficial femoropopliteal artery disease

BACKGROUND

Recurrent disease (restenosis) after endovascular treatment of the superficial femoral artery (SFA) remains a major problem. We evaluated the efficacy of beta-endovascular brachytherapy using the CORONA centering catheter in patients with SFA restenosis in a single-arm Phase II trial.

METHODS AND RESULTS

A total of 28 patients (mean age 70 years; 16 female, 12 male) with recurrent SFA stenosis were treated, and in-stent restenosis was present in 17 patients (61%). Brachytherapy was performed with strontium-90 beta source using a 7-French CO(2)-filled one-segment centering catheter. New stents had to be applied in two cases. Mean interventional length was 129 mm (range 20-240 mm). A dose of 14 Gy in vessel radius (postinterventional) plus 2 mm was applied in 24 patients and 18.4 Gy in four patients. Treatment time was 7 min 32 s per radiation segment. No major adverse events occurred. Patients were followed by ankle-brachial index and duplex sonography for a median of 42 months. Cumulative restenosis rates at 1, 2, and 3 years were 9%, 28%, and 40%, respectively. Target vessel revascularization was performed in seven cases (25%).

CONCLUSIONS

In comparison to literature data, the treatment of SFA restenosis with beta brachytherapy may improve long-term patency.

Atualização sobre endopróteses vasculares (stents): dos estudos experimentais à prática clínica

Atualmente, o tratamento das doenças vasculares periféricas é uma das áreas da medicina de maior expansão. O número de intervenções vasculares aumenta e os resultados das novas técnicas endovasculares estão muito próximos aos das tradicionais cirurgias vasculares. Embora a angioplastia ofereça bons resultados em curto prazo, o implante de stents procura melhorar o sucesso do procedimento e estender o seu uso a um número maior de pacientes com doença vascular periférica. Entretanto, a sua utilização ainda é controversa. O implante de stents no sistema aorto-ilíaco tem bons resultados; porém, a sua indicação para as lesões femoro-poplíteas ainda é discutida. Além disso, o rápido desenvolvimento de stents e sua escolha para uso no sistema vascular periférico têm sido uma difícil tarefa para o cirurgião endovascular. Muitos fatores influenciam a escolha do stent, e um amplo conhecimento desse material é essencial. Tal escolha depende da avaliação pré-operatória, da localização e das características da lesão e também do uso do stent primário ou seletivo. Nesse trabalho, são realizadas revisão do histórico do desenvolvimento dos stents, desde os estudos experimentais até os ensaios clínicos e também discussão sobre a sua aplicação no tratamento das doenças vasculares periféricas.

Current Treatment of Peripheral Arterial Disease

Despite advances in medical therapies to help prevent the development of atherosclerosis and improve the management of patients with established peripheral arterial disease (PAD), the prevalence of PAD and associated morbidity remains high. Over the past decade, percutaneous revascularization therapies for the treatment of patients with PAD have evolved tremendously, and a great number of patients can now be offered treatment options that are less invasive than traditional surgical options. With the surgical approach, there is significant symptomatic improvement, but the associated morbidity and mortality preclude its routine use. Although newer percutaneous treatment options are associated with lower procedural complications, the technical advances have outpaced the evaluation of these treatments in adequately designed clinical studies, and therapeutic options are available that may not have been rigorously investigated. Therefore, for physicians treating patients with PAD, an understanding of the various therapies available, along with the inherent benefits and limitations of each treatment option is imperative as a greater number of patients with PAD are being encountered.

Reduction of Stenosis Due to Intimal Hyperplasia After Stent Supported Angioplasty of Peripheral Arteries by Local Administration of Paclitaxel in Swine

PURPOSE

To assess if local intra-arterial administration of paclitaxel using drug-coated balloons or an admixture of paclitaxel to contrast medium inhibits stenosis after percutanous transluminal angioplasty (PTA) of peripheral arteries in a porcine overstretch model.

METHODS

Neointimal proliferation and stenosis were induced by overstretch and stenting of 40 peripheral arteries in 20 pigs. Paclitaxel was administered locally during PTA using coated balloons (n = 20) or dissolved in contrast medium (n = 10). Conventional balloons and contrast medium were used in a control group (n = 10). Reangiography with quantitative analysis was performed after 5 weeks.

RESULTS

On reangiography diameter stenosis and late lumen loss were significantly reduced by both methods of local drug delivery compared with control group; minimal luminal diameter was significantly larger in the treatment groups.

CONCLUSIONS

Local short-term administration of paclitaxel during PTA of peripheral arteries using balloons or contrast medium as drug carriers reduced stenosis due to intimal hyperplasia.

External Beam Irradiation and Restenosis Following Femoral Stenting: Long-Term Results of a Prospective Randomized Study

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.

Endovascular Therapies for Noncoronary Atherosclerosis in the Elderly: Aortoiliac and Femorotibial Lesions

Many interventional cardiologists are becoming interested in the interventional treatment of noncoronary atherosclerotic disease. The elderly may be especially benefited by the application of many new techniques for the treatment of lower limb atherosclerosis, such as protection and thromboaspiration devices, new atherectomy devices, and cryoplasty. In this review the authors offer geriatric cardiologists an overview and an update of the most recent advances in techniques and results in the field of interventional treatment of aortoiliac and femorotibial artery atherosclerosis in the elderly.

A Phase II study of external-beam radiotherapy and endovascular brachytherapy with PTA and stenting for femoropopliteal artery restenosis

PURPOSE

To assess the safety and seek evidence of efficacy of combined external-beam radiotherapy (EBRT) and endovascular brachytherapy in the treatment of stenotic vascular lesions.

METHODS AND MATERIALS

Seventeen patients with high risk for restenosis of femoropopliteal arteries were enrolled in this study from February 2000 to August 2002. The external beam radiotherapy regimen consisted of 10 Gy in 5 fractions of 2 Gy, starting on Day 0. This was followed on Day 6 by angiography, stent placement, and intraluminal brachytherapy to a dose of 10 Gy at 1.2 mm from stent surface. The EBRT was continued from the same day to another 10 Gy in 2 Gy daily fractions for 5 days.

RESULTS

The follow up ranged from 33 months to 60 months. At the time of analysis 15 of 17 patients were alive with patent stents. Of these, 10 were symptom-free. Two patients died of unrelated causes.

CONCLUSIONS

The combination of EBRT and endovascular brachytherapy provided adequate dose distribution without any geographical miss or "candy wrapper" restenosis. No incidence of aneurysmal dilation of radiated vascular segment was observed. The treatment was feasible, well tolerated, and achieved 88% stenosis free survival.

Endovascular Brachytherapy After Femoropopliteal Balloon Angioplasty Fails to Show Robust Clinical Benefit Over Time

PURPOSE

To determine if the short-term efficacy of adjunctive endovascular brachytherapy (EVBT) is maintained over time in patients undergoing balloon angioplasty (BA) of femoropopliteal atherosclerotic lesions.

METHODS

To evaluate the long-term clinical and angiographic outcome of EVBT, 147 consecutive patients (82 men; mean age 70.8+/-8.5 years) with 147 treated limbs were randomized to BA with (n=72, 49%) or without (n=75, 51%) adjunctive EVBT (12 or 14-Gy from an (192)Ir source, no centering, a 5-mm reference depth). Sixty-eight (46%) limbs were treated for de novo and 79 (54%) for recurrent femoropopliteal lesions. Clinical follow-up at 1, 3, 6, and 12 months and annually thereafter included evaluation of symptoms, ankle-brachial index (ABI), and intra-arterial angiography for new/worsening symptoms or at follow-up between 2 and 5 years. Sustained clinical success was defined as improvement in ABI >or=0.1 and/or of symptoms without repeated target lesion revascularization. Angiographic restenosis was defined as >or=50% diameter reduction. Subgroup analysis was performed for de novo versus recurrent lesions.

RESULTS

Mean clinical follow-up was 32.3+/-21.5 months. Angiographic follow-up was available in 83 (56%) patients (41 BA and 42 BA+EVBT) at a mean 31.8+/-20.7 months. Cumulative sustained clinical success rates at 1, 2, and 3 years, respectively, were 84.3%, 82.1%, and 76.4% after BA versus 82.4%, 69.8%, and 67.5% after BA+EVBT (p=0.26 by log-rank). Although the proportion of patients undergoing follow-up angiography was moderate, the freedom from angiographic restenosis at 1, 2, and 3 years was 70.7%, 63.1%, and 47.1% after BA versus 82.7%, 64.3%, and 64.3% after BA+EVBT (p=0.16 by log-rank). No differences were found between BA and BA+EVBT outcomes in patients with de novo versus recurrent femoropopliteal lesions.

CONCLUSION

The seemingly beneficial short-term effects of BA+EVBT are not sustained in the longer term, with no robust clinical improvement after angioplasty of atherosclerotic de novo or recurrent femoropopliteal lesions at up to 5 years.

Beta radiation in the treatment of in-stent restenosis of an in situ saphenous vein bypass graft A case report

We describe a case of instent restenosis in a femoral-distal saphenous vein bypass graft successfully treated with brachytherapy. A 45-year-old insulin-requiring diabetic woman underwent an in-situ femoral-anterior tibial bypass graft for a non-healing ischemic ulcer. Despite a technically successful percutaneous transluminal angioplasty and endovascular stenting of a retained valve within the threatened graft, the wound failed to heal. At the 1-month follow-up, instent restenosis was documented and successful cutting balloon angioplasty, complemented by adjunctive beta-irradiation was successfully performed. Clinical and hemodynamic success was achieved, with prompt ulcer healing and intermediate-term graft patency maintained on surveillance duplex ultrasound follow-up. We review the literature on radiation therapy in the management of peripheral arterial disease and discuss therapeutic options in the management of restenosis.

Endovascular gamma irradiation for the prevention restenosis after angioplasty of femoropopliteal de novo stenoses

The purpose of this study was to investigate the effectiveness and detect side effects of centered, overlapped endovascular gamma irradiation after angioplasty of de novo femoropopliteal stenoses. Thirty patients (age 65.3+/-9.2 years) with arterial occlusive disease were prospectively enrolled to receive endovascular gamma irradiation (192-iridium, 14 Gy centered at 2 mm vessel wall) immediately after percutaneous transluminal angioplasty (PTA) of femoropopliteal stenoses. Irradiation overlapped dilatation by 1-2 cm at each end. Follow-up involved angiography after 12 months; duplex sonography; and interviews before and after PTA and at 1, 6, and 12 months follow-up. PTA and centered endovascular irradiation were performed successfully in all patients. Three thromboembolic complications occurred during irradiation. Angiographic and clinical follow-up was possible in 28 patients. The angiographic degree of stenosis was 73.8%+/-16.3% before and 3.6%+/-23.5% after PTA and was 3.5%+/-43.7% at the 1-year follow-up. Restenosis (>50%) of the target lesion developed in three patients (10.7%) and edge stenoses (>30%) in nine patients (32.1%). An aneurysm of the irradiated segment in one patient was treated by stenting. The rate of retreatment was 17.9%. The vessel diameter after endovascular gamma irradiation and PTA of femoropopliteal stenoses remained stable. Restenosis, induction of edge stenoses, and aneurysm were reasons for reinterventions.

Endovascular Brachytherapy: Restenosis in de Novo versus Recurrent Lesions of Femoropopliteal Artery—The Vienna Experience

PURPOSE

To determine the effectiveness of endovascular brachytherapy in the prevention of restenosis in recurrent versus de novo femoropopliteal lesions.

MATERIALS AND METHODS

Ethics committee approval and patient informed consent were obtained. After they had undergone femoropopliteal angioplasty, 199 patients (mean age, 71.9 years +/- 9.6; 115 men, 84 women) were treated with either percutaneous transluminal angioplasty (PTA) and brachytherapy (n = 100) or PTA alone (n = 99). The patients were part of prospective randomized trials, the Vienna 2 and 3 trials, and were evaluated according to the stratification criterion of de novo or recurrent disease. Sixty-six of 134 patients with a de novo lesion and 34 of 65 patients with a recurrent lesion were randomly assigned to the PTA and brachytherapy arm; the remaining patients were treated with PTA alone. Outcomes were compared between the groups. The Student t test or one-way analysis of variance was used to compare continuous variables, and the chi2 test or Fisher exact test was used to assess dichotomous variables. Kaplan-Meier curves were calculated, and the log-rank test was performed to determine freedom from recurrence at 12 months in both groups. A multivariate Cox proportional hazard regression analysis was performed to evaluate the multivariate predictors of recurrence at 12-month follow-up.

RESULTS

For patients with de novo lesions, the frequency of recurrence at 12 months was not significantly different between those who underwent brachytherapy and PTA and those who underwent PTA alone (24 [36%] of 66 patients vs 30 [44%] of 68 patients, P = .32). For patients with recurrent lesions, however, the 12-month recurrence rate was significantly lower in those who received brachytherapy than in those who did not (nine [26%] of 34 patients vs 22 [71%] of 31 patients, P = .004).

CONCLUSION

Endovascular brachytherapy with gamma radiation significantly reduces the restenosis rate after femoropopliteal angioplasty of recurrent but not de novo lesions.

Vascular Brachytherapy with192Ir after Femoropopliteal Stent Implantation in High-Risk Patients: Twelve-month Follow-up Results from the Vienna-5 Trial

PURPOSE

To prospectively evaluate the effectiveness of endovascular brachytherapy in the prevention of restenosis after femoropopliteal stent implantation in high-risk patients.

MATERIALS AND METHODS

Patients provided written informed consent to participate in this study, which was approved by the ethics committee. A total of 88 patients (mean age, 67.7 years +/- 10.1; 57 men [65%], 31 women [35%]) with femoropopliteal lesions (mean treatment length, 16.8 cm +/- 7.3) were included. Patients underwent percutaneous transluminal angioplasty (PTA) and stent implantation and were randomized in a double-blind fashion to undergo either gamma brachytherapy with an iridium 192 source or treatment with nonradioactive seeds. A 14-Gy dose of iridium 192 was prescribed at 2 mm into the arterial wall (target depth equals vessel radius plus 2 mm). The primary end point of the study was angiographic binary restenosis of more than 50% at 6-month follow-up. Secondary end point was either percutaneous or surgical target lesion revascularization after 6 months. Continuous data are presented as mean +/- standard deviation. Categorical data are expressed as percentages. Student t test was used to compare continuous data; chi(2) test was used to compare categorical values. Survival function was calculated with the Kaplan-Meier method. Multivariate Cox proportional hazard regression analysis was performed to enable evaluation of multivariate predictors of recurrence at 6- and 12-month follow-up. Variables included brachytherapy, clinical stage, lesion length, de novo and recurrent lesion, vessel run off, prior stenosis or occlusion, diabetes mellitus, and stent model.

RESULTS

Revascularization and brachytherapy were accomplished successfully in all patients. The overall 6-month recurrence rate was 35% in patients who underwent only stent implantation and 33% in patients who underwent both stent implantation and brachytherapy (P = .89). Nine (10%) patients developed early reocclusion in the segment treated with a stent (two patients [4%] in the stent group and seven [17%] in the stent and brachytherapy group); of these patients, three in the stent and brachytherapy group experienced reocclusion within 24 hours of the intervention. Late (>30 days after intervention) thrombotic occlusion was observed in three patients (7%) in the stent and brachytherapy group.

CONCLUSION

Brachytherapy does not improve 6-month patency after femoropopliteal stent implantation in high-risk patients because of a high incidence of early and late thrombotic occlusion.

Radiation therapy induced modulation of wound healing at experimental vein graft anastomoses

OBJECTIVES

The aim of this study was to investigate if radiation therapy (RT) favorably modulates wound healing at vein graft anastomoses.

MATERIALS AND METHODS

Jugular vein grafts were sewn into carotid arteries in 32 rats which were randomly divided into two groups: RT (gamma source, 14 Gray, n=16) and control (C, sham irradiation, n=16). Grafts and adjacent arteries were analyzed at 2 (n=8) and 8 weeks (n=8) by histology, immunohistochemistry, and morphometry.

RESULTS

Although, RT did not reduce the overall occurrence of intimal hyperplasia, the distribution differed. RT led to a reduction of intimal hyperplasia in arterial segments (median: C: 41.873 microm2; RT: 6.452 microm2, p < 0.0007). In contrast, RT augmented intimal hyperplasia in vein grafts (median: C: 30.287 microm2; RT: 90.455 microm2, p < 0.014). Vein graft diameters after RT were enlarged (median: C: 2.098 microm; RT: 3.381, p < 0.031). Over 80% of the cells were of mesenchymal origin in both groups.

CONCLUSIONS

RT reduced intimal hyperplasia in arterial segments. However, RT led to graft dilatation and increased intimal hyperplasia in vein grafts. RT did not favorably modulate the vascular wound healing response in this model.

Advances in vascular brachytherapy over the last 10 years: focus on femoropopliteal applications

Restenosis and the need for repeated interventions after percutaneous transluminal angioplasty (PTA) remain major drawbacks limiting a widespread application of this minimally invasive technique in the femoropopliteal segment. During the last decade, vascular brachytherapy (BT) emerged as a promising, novel technology with the potential to reduce the rates of restenosis. Meanwhile, several randomized controlled trials have suggested beneficial short and midterm effects of BT in the femoropopliteal arteries. However, despite substantial advances, many questions remain regarding the utility of vascular BT and its dissemination as a practical tool to prevent restenosis. The risk of complications, such as late stent thrombosis, edge effect, catch-up late restenosis, and potential aneurysm formation, as well as the logistical issues associated with the use of this technology in the catheterization laboratory, are delaying the acceptance of BT for routine use. This article reviews the developments of BT for restenosis prevention during the past decade, focusing on implications for peripheral endovascular treatment.

Centered endovascular irradiation to prevent postangioplasty restenosis of arteriovenous fistula in hemodialysis patients; Results of a feasibility study

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.

Endovascular brachytherapy prevents restenosis after femoropopliteal angioplasty: results of the Vienna-3 randomised multicenter study

BACKGROUND AND PURPOSE

The aim of the trial was to investigate the effect of Iridium-192 gamma endovascular brachytherapy on reduction of restenosis after femoropopliteal angioplasty.

PATIENTS AND METHODS

Between Oct, 1998 and Jul, 2001 a total of 134 patients have been randomized after successful angioplasty to brachytherapy or sham irradiation in a prospective, randomized, multicenter, double blind controlled trial. Patients with de novo lesion of at least 5 cm or recurrent lesion of any length after prior angioplasty have been enrolled. Brachytherapy was performed with 7F centering catheter. Mean lesion length was 9.1cm (1.5-25 cm) and mean intervention length 13.6 cm (4-27.5 cm) in brachytherapy cohort.

RESULTS

In placebo cohort mean lesion length was 10.3 cm (2-25 cm) and mean intervention length 14.1 cm (2-29 cm). A dose of 18 Gy was prescribed 2 mm from the surface of centering balloons. Analyzed (based on angiography) on intention to treat basis the binary restenosis rate at 12 months was 41.7% (28/67) in brachytherapy cohort and 67.1% (45/67) in placebo cohort (chi2 test, P<0.05). Corresponding data for as treated analysis (A total of 38 patients was excluded from analysis due to lack of follow-up, early recurrence within 30 days and >30% residual stenosis after angioplasty) have been 23.4% in the brachytherapy and 53.3% in the placebo group (P<0.05), respectively. The cumulative patency rates after 24 months on intention to treat analysis were 54% in the brachytherapy and 27% in the placebo group (P<0.005). Corresponding data for as treated analysis were 77% in the brachytherapy and 39% in the placebo group (P<0.001). Late thrombosis was not seen.

CONCLUSIONS

Significant reduction of restenosis rate was obtained with endovascular gamma brachytherapy after femoropopliteal angioplasty.

External beam radiation therapy reduces the rate of re-stenosis in patients treated with femoral stenting: results of a randomised study

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.

Treatment parameters for beta and gamma devices in peripheral endovascular brachytherapy

PURPOSE

To determine dosimetric parameters, such as radial and longitudinal dose profiles, for beta and gamma devices in peripheral endovascular brachytherapy.

METHODS AND MATERIALS

An (192)Ir high-dose rate stepping source, a (90)Sr source train, and a (32)P-coated radiation balloon were investigated. The treatment-planning software PLATO, Monte Carlo code EGSnrc, and GafChromic film dosimetry were used to analyze the dose distribution of these devices.

RESULTS

For a 5-mm-diameter vessel, the ratio between the dose at 2 mm depth and the dose at the lumen surface was 1.8, 3.4, and 16.2 for the (192)Ir, (90)Sr, and (32)P devices, respectively. The dose variation at the reference depth of 2 mm into the vessel wall was 7-18 Gy, for different analyzed dose prescriptions. The reference lumen dose was different by a factor >8. For all three devices, the reference isodose length was not <5 mm on the proximal and distal edge of the active source length.

CONCLUSIONS

A complete set of dose parameters for beta and gamma sources has to be considered for appropriate treatment planning and performance, including reporting of reference depth dose, reference lumen dose, and reference isodose length.

Subintimal angioplasty for infrainguinal occlusive disease

Subintimal angioplasty is a relatively new endovascular approach for the treatment of patients with femoropoliteal or tibial artery occlusion. The procedure involves intentionally creating a false channel or dissection around an arterial occlusion, then reentering the true lumen distally. The procedure has a relatively low incidence of complications and a high rate of technical success.Short-term patency has been fair in some reports and poor in others. Long-term results are not available. Aspirin and possibly anticoagulation or antiplatelet agents may improve technical success and short-term patency. Further studies with longer follow-up are required before it can be recommended as a potentially viable alternative to arterial bypass.

External beam radiotherapy fails to prevent restenosis after iliac or femoropopliteal percutaneous transluminal angioplasty: results of a prospective randomized double-blind study

PURPOSE

Early restenosis is one of the major complications after successful percutaneous transluminal angioplasty (PTA), in main, as well as peripheral, arteries. The effectiveness of hypofractionated external beam radiotherapy (EBRT) as a prophylaxis for restenosis was examined in a prospective, randomized, double-blind, clinical trial.

METHODS AND MATERIALS

Forty-eight patients underwent sham RT and 47 were treated with daily RT in 3-Gy fractions, to a total dose of 21 Gy. The follow-up lasted for 12 months, and the examinations included pressure measurements and calculations of the ankle-brachial index or duplex sonography ("peak velocity ratio"). If restenosis was suspected, additional angiography was performed.

RESULTS

No statistically significant difference was found between the treatment groups: sham RT 16 failures (33.3%) and EBRT group 21 failures (45.7%; p = 0.292). EBRT also showed no substantial effects on subgroups classified by the specific length of the lesion or in diabetic patients.

CONCLUSION

External beam radiotherapy does not prevent restenosis. A reduction in the failure rate >8% using fractionated EBRT with doses aimed at keloid prevention can be ruled out with a probability of 97.5%. Endovascular brachytherapy remains the preferred therapeutic method for achieving restenosis prophylaxis through RT.

Vascular brachytherapy in renal artery restenosis

PURPOSE OF REVIEW

As renal artery stenting becomes more commonly performed, the prevalence of renal artery in-stent restenosis will increase. Intracoronary brachytherapy is the only adjuvant therapy that has been shown to reduce the incidence of recurrent restenosis. This review addresses the mechanisms that make brachytherapy an effective tool for restenosis and its application to renal arteries.

RECENT FINDINGS

To date, the literature on renal artery brachytherapy for restenosis consists of several singular case reports and two case series. The first series of 13 patients had a 20% restenosis rate 1 year after brachytherapy, when Doppler ultrasound was used for follow-up monitoring. A report of a series of 5 patients, published this year, used surrogate markers for assessing efficacy as endpoints and found a similar restenosis rate.

SUMMARY

These series and case reports demonstrate that renal brachytherapy is feasible and safe. Comments on efficacy must await a randomized trial or accumulation of more anecdotal data.

De Novo Femoropopliteal Stenoses: Endovascular Gamma Irradiation Following Angioplasty—Angiographic and Clinical Follow-up in a Prospective Randomized Controlled Trial

PURPOSE

To assess and report the follow-up results of a randomized controlled trial on centered endovascular gamma irradiation performed after percutaneous transluminal angioplasty (PTA) for de novo femoropopliteal stenoses.

MATERIALS AND METHODS

Thirty patients who underwent PTA for de novo femoropopliteal stenoses were randomly assigned to undergo 14-Gy centered endovascular irradiation (irradiation group, n = 15) or no irradiation (control group, n = 15). Intraarterial angiography was performed 6, 12, and 24 months after treatment; duplex ultrasonography (US), the day before and after PTA and 1, 3, 6, 9, 12, 18, and 24 months later. Treadmill tests and interviews were performed the day before PTA and 1, 3, 6, 9, 12, 18, and 24 months later. Results of angiography, duplex US, treadmill tests, and interviews were evaluated with the nonpaired t or the Fisher exact test.

RESULTS

Baseline characteristics did not differ significantly between the two groups. Mean absolute individual changes in degree of stenosis, compared with the degrees of stenosis shortly after PTA, in the irradiation group versus in the control group were -10.6% +/- 22.3 versus 39.6% +/- 24.6 (P <.001) at 6 months, -2.0% +/- 34.2 versus 40.6% +/- 32.6 (P =.002) at 12 months, and 7.4% +/- 43.2 versus 37.7% +/- 34.5 (P =.043) at 24 months. The rates of target lesion restenosis at 6 (P =.006) and 12 (P =.042) months were significantly lower in the irradiation group. The numbers of target lesion re-treatments were similar between the groups, but target vessel re-treatments were more frequent in the irradiation group. There were no significant differences in interview or treadmill test results between the two groups at t test analysis.

CONCLUSION

The degree of stenosis was significantly reduced 6, 12, and 24 months after angioplasty of de novo femoropopliteal stenoses in the patients who underwent endovascular irradiation.

Endovascular Brachytherapy: Effect on Acute Inflammatory Response after Percutaneous Femoropopliteal Arterial Interventions

PURPOSE

To investigate whether endovascular brachytherapy diminishes vascular inflammation in response to femoropopliteal percutaneous transluminal angioplasty (PTA) or stent implantation in two double-blind randomized-controlled trials.

MATERIALS AND METHODS

Forty-seven consecutive patients from two double-blind randomized-controlled trials were studied. Patients either underwent femoropopliteal PTA with endovascular gamma irradiation (n = 8) or placebo irradiation (n = 7) or underwent PTA and stent implantation with brachytherapy (n = 15) or placebo irradiation (n = 17). High-sensitivity C-reactive protein (CRP), serum amyloid A (SAA), and fibrinogen levels were measured at baseline and 8, 24, and 48 hours after the intervention. The change of acute phase parameters from baseline to 48 hours after intervention indicated the extent of the inflammatory response and was compared between patients undergoing brachytherapy and those undergoing placebo irradiation. Fisher exact test was used for comparison of categorical data, and nonparametric statistical methods were applied for analysis of continuous data (Mann-Whitney U tests for unpaired data and Friedman analysis for repetitive measurements).

RESULTS

Median patient age was 70 years (interquartile range, 56-74 years); 33 (70%) patients were men and 14 (30%) were women. Clinical characteristics and baseline values of acute phase parameters were similar between groups. A statistically significant increase in CRP, SAA, and fibrinogen values was observed after PTA and stent implantation, both in the patients who underwent brachytherapy and in those who underwent placebo irradiation. Compared with placebo irradiation, however, brachytherapy did not significantly reduce any acute phase parameter from baseline to 8, 24, or 48 hours after the intervention (P >.05 for all comparisons).

CONCLUSION

Endovascular brachytherapy did not diminish early vascular inflammation in response to PTA or stent implantation and even induced a trend toward an increased inflammatory response.

Intravascular brachytherapy: indications and management of adverse events

Intravascular brachytherapy has become the standard of care for the treatment of coronary in-stent restenosis after repeat angioplasty. More than 5000 patients have been treated as part of various clinical trials. Based on the results of the GAMMA I trial, the START ((90)Sr Treatment of Angiographic Restenosis Trial), and the INHIBIT (INtimal Hyperplasia Inhibition with Beta In-stent restenosis Trial), the Checkmate system using (192)Ir, the Betacath system using (90)Sr/Y, and the Galileo system using (32)P, have been approved for the treatment of in-stent restenosis. With a better understanding and application of radiation oncology concepts to vascular brachytherapy, problems such as edge failure are being overcome. The complication of late thrombosis has also become less significant with the elimination of restenting at the brachytherapy procedure, and the prolonged use of antiplatelet therapy. There are other competing modalities in the early phases of clinical trials. The durability of results, lack of any significant long-term complications and the confirmation of the efficacy in other sites will further consolidate the role of radiation in treating in-stent restenosis.

Optimal therapeutic approaches to femoropopliteal artery intervention

Superficial femoral artery disease presents a complex challenge for therapy. The extent of vascular involvement may vary from focal disease with symptoms of intermittent claudication to long total occlusions manifest as critical limb ischemia. Optimal therapy requires understanding the available options including exercise programs, pharmacologic medical therapy, surgery and interventional endovascular therapy. Rapidly advancing endovascular technology for enabling safe intervention in complex, long occlusive segments of the superficial femoral artery continues to emerge. New devices like the SafeCross wire, Excimer laser, Silverhawk Atherectomy catheter, Cryoplasty catheter and new generations of bare metal and drug-eluting nitinol stents are shifting the paradigm for therapy from surgical to more endovascular treatment even for the most complex disease presentation.

Endovascular gamma irradiation of the iliac arteries: 1-year results from a clinical safety and feasibility study

PURPOSE

To estimate safety and feasibility of vascular brachytherapy in iliac arteries.

METHODS

Fourteen patients (11 men; mean age 56.7+/-9.9 years, range 44-81) with occlusive disease in 15 iliac arteries (7 external, 8 common) were treated with balloon dilation followed by irradiation from an iridium 192 source (15 Gy at 3 mm from the inner surface of the artery wall) applied with a PARIS centering catheter and bilateral 10-mm margins. Patients receiving stents for suboptimal angioplasty were prescribed a 6-month course of antiplatelet treatment with ticlopidine. Angiography was routinely scheduled for 6 months after intervention.

RESULTS

There were no complications of the angioplasty procedure or EVBT treatment; 7 patients received stents for dissection or residual stenosis. Mean follow-up was 12.4+/-6.0 months. At 6-month angiography, 1 (6.7%) restenosis in a common iliac artery stent was found. Another patient with a common iliac artery stent developed transient lower limb ischemia at 4 months, probably due to temporary suspension of antiplatelet treatment and distal disease.

CONCLUSIONS

Brachytherapy in the iliac arteries appears to be feasible and safe; longer follow-up in more patients is needed to determine its clinical utility in the prevention of restenosis.