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

The birth, decline, and contemporary re-emergence of endovascular brachytherapy for prevention of in-stent restenosis

Despite the advent of drug-eluting stents and dual antiplatelet therapy in the interventional management of cardiovascular disease, restenosis rates remain high with significant sequelae. Endovascular brachytherapy-popular in the 1990s and early 2000s-has recently resurfaced as a cost-effective treatment option. In this work, we outline the history of endovascular brachytherapy starting with its earliest promise in the 1990s. We discuss the development of drug-eluting stents and dual antiplatelet strategies and their impact on the perceived benefit of endovascular brachytherapy. For the contemporary era, we propose novel roles for endovascular brachytherapy in complex coronary artery disease and in high-risk patients managed with drug-eluting stents. We discuss the impetus for reducing the requirement and duration of dual antiplatelet therapy using endovascular brachytherapy. We also review innovative opportunities for endovascular brachytherapy after bare-metal stent placement in both coronary and noncoronary territories and offer economic arguments in favor of endovascular brachytherapy. Trials of endovascular brachytherapy in these regimes are merited.

Comparative Effectiveness of Endovascular Treatment Modalities for De Novo Femoropopliteal Lesions: A Network Meta-analysis of Randomized Controlled Trials

Purpose: To report the results of a network meta-analysis of randomized controlled trials (RCTs) comparing multiple endovascular treatments for de novo femoropopliteal lesions. Materials and Methods: The MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials databases were systematically searched on June 1, 2019, for prospective RCTs comparing 14 treatments [ie, atherectomy, brachytherapy, cryoplasty, cutting balloons, drug-coated balloons, bare nitinol stents, drug-eluting stents (DES), covered stents (CS), and combinations] in the treatment of de novo femoropopliteal lesions. Outcomes were technical success; binary restenosis and target lesion revascularization (TLR) at 6, 12, and/or 24 months; and all-cause mortality at 12 months. Ultimately, 53 articles reporting on 45 studies (91 study arms; 5565 patients) were selected. For the technical success outcome, all types of stents, all balloons, and all atherectomy devices were aggregated in stent, balloon, and atherectomy technology groups, respectively. Results: In terms of technical success for aggregated treatment types, stent technology was the most effective treatment and was better than balloon and atherectomy technologies. In terms of binary restenosis, DES was the most effective single treatment at the 6- and 12-month follow-up and CS at the 24-month follow-up. Both DES and CS were better than the majority of other single treatments, including balloon angioplasty, cutting balloon, cryoplasty, directional atherectomy, and bare nitinol stent during all follow-up periods. In terms of TLR, DES was the second most effective single treatment and the most effective single treatment at the 6- and 12-month follow-up intervals; CS was the most effective single treatment at the 24-month follow-up. Both DES and CS were better than the majority of other single treatments. The 12-month all-cause mortality of both DES and CS were similar to other treatments, whereas cryoplasty seemed to be the least effective treatment with regard to binary restenosis and TLR. Conclusion: Both DES and CS had substantial advantages in terms of restenosis and TLR in femoropopliteal lesions and were similar to aggregate stent technology in terms of technical success. DES performed better within 12 months after operation and CS at ~24 months, but neither had much advantage in terms of mortality. In contrast, cryoplasty seemed to be a less effective treatment.

Comparison of Drug-Eluting Stent with Bare-Metal Stent Implantation in Femoropopliteal Artery Disease: A Systematic Review and Meta-Analysis

BACKGROUND

This study aimed to perform a systematic review and meta-analysis of current evidence comparing the drug-eluting stent (DES) with the bare-metal stent (BMS) in the treatment of femoropopliteal artery disease (FPAD).

METHODS

All relevant articles reporting the results of DES versus BMS implantation in FPAD were systematically searched in MEDLINE, EMBASE, and Cochrane database. Randomized controlled trial (RCT), cohort, and retrospective study were all included. The efficacy end points included late lumen loss (LLL), binary restenosis, primary patency rate, freedom from target lesion revascularization (TLR), and stent fracture. Related data of the follow-up outcomes were extracted and pooled. For each end point, odds ratios (ORs) and 95% confidence intervals (CIs) were calculated.

RESULTS

A total of 9 studies with 776 patients were included in this meta-analysis. There was no statistically significant difference between the DES and BMS groups in terms of LLL at 6 months (standard mean difference = -0.37, P = 0.07); binary restenosis at 6, 12, and 24 months (OR = 0.44, P = 0.20; OR = 0.75, P = 0.74; and OR = 0.62, P = 0.36; respectively); primary patency rate at 6, 12, and 24 months (OR = 1.18, P = 0.73; OR = 1.43, P = 0.70; OR = 1.25, P = 0.68, respectively); freedom from TLR at 12 months (OR = 1.13, P = 0.79); and stent fracture at 6 months (OR = 1.67, P = 0.38). A sensitivity analysis demonstrated that there was a significant benefit in the DES group over the BMS group in binary restenosis at 6 months (OR = 0.22, P = 0.008) after excluding a retrospective study, whereas no significant difference was observed when eliminating any other study. A subgroup analysis did not reveal any significant difference between a subgroup (sirolimus-eluting stent or paclitaxel-eluting stent) and the BMS group in FPAD.

CONCLUSIONS

According to current evidence, DES was not superior to BMS in the treatment of FPAD. Further larger RCTs are needed to provide more evidence in the comparison between DES and BMS for FPAD.

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.

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.

Relationship Between Primary Patency and Lesion Length Following Bare Nitinol Stent Placement for Femoropopliteal Disease

PURPOSE

To evaluate the relationship between 1-year primary patency and lesion length in patients with femoropopliteal disease treated with bare nitinol stents.

METHODS

The study was a retrospective analysis of a prospectively maintained multicenter database. Between January 2004 and December 2011, 1047 consecutive patients (mean age 72 years; 765 men) underwent femoropopliteal stenting with nitinol stents in 1373 limbs. The mean vessel diameter was 5.3±0.7 mm and the mean lesion length was 142±75 mm. One-year follow-up data were collected and analyzed to ascertain which lesion length would be expected to demonstrate a 1-year primary patency above the established 66% objective performance goal (OPG).

RESULTS

The lower limit of the 95% confidence interval (CI) for the unadjusted 1-year primary patency was >66% when the lesion length was ≤243 mm. After adjustment of the covariates to match those of the OPG-derived population, the 1-year primary patency decreased linearly with longer lesion length. The 1-year primary patency was 83.2% (95% CI 79.8% to 86.1%) for a 100-mm lesion length, 76.4% (95% CI 71.7% to 80.5%) for a 200-mm lesion length, and 70.7% (95% CI 62.4% to 77.7%) for a 300-mm lesion length. The maximum lesion length providing a 1-year primary patency significantly greater than 66% was calculated to be 263 mm.

CONCLUSION

The 1-year primary patency of femoropopliteal lesions treated with bare nitinol stents decreased linearly with longer lesion length. The maximum lesion length providing a higher patency rate than the OPG of 66% was ~25 cm.

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.

Systematic review and meta-analysis of additional technologies to enhance angioplasty for infrainguinal peripheral arterial occlusive disease

Background

There are several additional techniques designed to enhance conventional percutaneous transluminal balloon angioplasty (PTA). This systematic review assessed current evidence on the clinical effectiveness of additional techniques for infrainguinal peripheral arterial occlusive disease (PAD).

Methods

Relevant electronic databases, including MEDLINE, were searched in May 2011. The population comprised participants with symptomatic PAD undergoing endovascular treatment for disease distal to the inguinal ligament. Interventions were additional techniques compared with conventional PTA. Main outcome measures were restenosis and need for reintervention. Randomized clinical trials (RCTs) of clinical effectiveness were assessed for quality and data were extracted. Where appropriate, meta-analysis was undertaken to produce risk ratios (RRs).

Results

Forty RCTs were selected. Meta-analysis showed a significant benefit in reducing restenosis rates at 6 months for self-expanding stents (RR 0·49) and drug-coated balloons (RR 0·40), and at 12 months for endovascular brachytherapy (RR 0·63). There was also evidence that use of a stent-graft significantly reduced restenosis compared with PTA, as did drug-eluting stents compared with bare-metal stents. Meta-analysis showed that use of drug-coated balloons was associated with significantly lower reintervention rates than PTA alone at 6 months (RR 0·24) and 24 months (RR 0·27) of follow-up. There was also evidence of significantly lower reintervention rates for self-expanding stents at 6 months. Other techniques did not show significant treatment effects for restenosis or reintervention.

Conclusion

The conclusions of this review should be tempered by small sample sizes, lack of clinical outcome measures and differing outcome definitions, making direct comparison across trials difficult. However, self-expanding stents, drug-eluting stents and drug-coated balloons appeared to be the most promising technologies worthy of future study.

Endovascular brachytherapy using liquid Beta-emitting rhenium-188 for the treatment of long-segment femoropopliteal in-stent stenosis

PURPOSE

To evaluate the efficacy and safety of endovascular brachytherapy with liquid beta-emitting rhenium-188 (Re-188) in patients with long-segment in-stent stenosis in the femoropopliteal segment.

METHODS

From July 2009 to April 2011, 90 consecutive patients (59 men; mean age 68.3±10.3 years, range 43-86) with symptomatic in-stent stenosis/occlusion (24.6-cm mean lesion length) of the femoropopliteal segment underwent angioplasty and subsequent endovascular brachytherapy. The liquid beta-emitting Re-188 was applied to the target lesion within an angioplasty balloon using a dose of 13 Gy at a depth of 2 mm into the vessel wall. Clinical and angiographic follow-up data were collected up to 2 years. The main study endpoints were the 6- and 12-month primary patency rates defined as <50% in-stent stenosis as detected by duplex ultrasound. Clinical endpoints were the cumulative rates of death, amputation, and bypass surgery, as well as improvement in the Rutherford category and the ankle-brachial index. Results were correlated with patient and lesion characteristics.

RESULTS

Primary technical success was achieved in all patients, with 1 early stent thrombosis, but no other complications related to the irradiation. Eighty-eight patients reached the 6-month and 82 the 12-month examinations; the primary patency was 95.2% and 79.8%, respectively. In-stent stenosis occurred in 9 patients, while 10 patients had reocclusion of the treated segment. During follow-up, there were 2 late acute thrombotic occlusions, both after discontinuation of clopidogrel. The clinical status improved in 67.0% and 62.2% of the patients after 6 and 12 months, respectively. No patient, lesion, or procedure variables were predictive of restenosis after EVBT.

CONCLUSION

EVBT with liquid beta-emitting Re-188 was safe and effective in preventing restenosis in long-segment femoropopliteal ISS.

Anti-inflammatory effects of low-dose radiotherapy. Indications, dose, and radiobiological mechanisms involved

Low-dose radiotherapy (LD-RT) has been used for several benign diseases, including arthrodegenerative and inflammatory pathologies. Despite its effectiveness in clinical practice, little is known about the mechanisms through which LD-RT modulates the various phases of the inflammatory response and about the optimal dose fractionation. The objective of this review is to deepen knowledge about the most effective LD-RT treatment schedule and radiobiological mechanisms underlying the anti-inflammatory effects of LD-RT in various in vitro experiments, in vivo studies, and clinical studies.

Endobronchial brachytherapy provides excellent long-term control of recurrent granulation tissue after tracheal stenosis

PURPOSE

To review the experience of using endobronchial brachytherapy (EBB) as a treatment for recurrent tracheal granulation tissue.

METHODS AND MATERIALS

Patients referred for EBB at the Rabin Medical Center for benign stenosis were reviewed with institutional review board approval. Patients underwent bronchoscopic resection of granulation tissue followed by insertion of self-expanding metallic stents. After stenting, repeat laser resection was done at least 1 week before brachytherapy. After CT simulation, patients had three-dimensional brachytherapy treatment planning. A single 10-Gy dose was prescribed to 1.0cm from the source and treatment was delivered using high-dose-rate afterloader with (192)Ir source. Patients were followedup with bronchoscopy every 3 months after the completion of therapy.

RESULTS

From November 2001 to January 2009, 29 patients were treated with EBB to prevent granulation tissue reformation. Median age was 70 years and 55% of patients were male. Ninety percent of patients were treated to the trachea and the remaining patients had stenoses in the main stem bronchi. The primary cause of stenosis was prolonged mechanical ventilation (76%). The median time from stent placement to brachytherapy was 69 days. Median active length of treatment was 7cm. With a median followup of 36 months, 66% (19 of 29) of patients remained free of granulation tissue. Forty-eight percent of patients have died, with all except 1 patient dying of their underlying condition. A single patient experienced death from tracheoesophageal fistula.

CONCLUSION

EBB is an effective and safe treatment to prevent recurrent granulation tissue formation after endobronchial resection and should be considered in patients who are unable to undergo surgical resection.

Endovascular brachytherapy and restenosis following lower limb angioplasty: Systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Restenosis is a fundamental weakness of percutaneous femoropopliteal angioplasty (PTA). The potential of endovascular brachytherapy (EVBT) to reduce restenosis has been evaluated in randomized clinical trials, but no pooled analysis has been undertaken.

METHODS

A systematic review was undertaken to identify randomized controlled trials in which PTA alone was compared to PTA plus EVBT. The Pubmed and Medline databases, American Heart Association OASIS database and conference proceedings from the Peripheral Vascular Surgery Society and Vascular Society of Great Britain and Ireland were searched. Eligible studies were randomised controlled trials comparing PTA to PTA plus EVBT in human subjects with at least one clinical outcome reported (restenosis, complications, patency). Study quality was assessed by the Jadad score. Random-effects modeling was used to generate pooled effect size estimates.

RESULTS

Six trials (687 patients) were identified. EVBT reduced 12-month restenosis rates (pooled odds ratio 0.50; 95% CI 0.301-0.836; p=0.008). The benefit disappeared by 24 months. The short-term risk of new lesions elsewhere in the treated artery was significantly increased by EVBT (pooled odds ratio 8.65; 95% CI 2.176-34.391; p=0.002).

CONCLUSIONS

While limited by the small sample sizes in the included trials, this analysis suggests that the early benefit of EVBT is counter-balanced by the increased risk of new lesions and the lack of medium- to long-term reductions in restenosis risk. Based upon the best available evidence, EVBT cannot be recommended for routine clinical 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.

[Intravascular brachytherapy for peripheral arterial occlusive disease: systematic review of medical efficacy and health economic modelling]

CONTEXT

Percutaneous transluminal angioplasties (PTA) using balloon dilatation with or without stenting are performed to treat peripheral arterial occlusive disease (PAOD). Intravascular brachytherapy (IB) after PTA promises to reduce the restenosis rates. The present article addresses questions concerning medical efficacy and cost-effectiveness of IB in PAOD patients.

METHODS

A systematic literature search for randomized controlled studies evaluating IB in PAOD was conducted in August 2007. Information synthesis was conducted using meta-analysis. Health economic modelling was performed on the basis of clinical assumptions derived from the meta-analysis and economical assumptions derived from the German Diagnosis Related Groups (G-DRG) 2007.

RESULTS

Twelve publications covering seven studies about IB vs. no IB were included in the evaluation. IB after successful balloon dilatation showed a significant reduction in the rate of restenosis at six and/or twelve months (relative risk 0.62; 95% confidence interval: 0.46 to 0.84) and a significant delay in the time to recurrence of restenosis (17.5 vs. 7.4 months, p < 0.01). IB after stenting did not lead to significant results regarding the restenosis rates, but was more often associated with early and late occlusive thromboses. The incremental cost-effectiveness ratio per restenosis avoided for IB vs. no IB after successful balloon dilatation was--depending on the G-DRG used-Euro 8,484 and Euro 9,058, respectively. In the comparison of IB vs. no IB after stenting IB was demonstrated to be inferior to no IB.

CONCLUSIONS

IB after successful balloon dilatation in PAOD can be recommended from a medical point of view. From the health economic perspective the answer is not yet clear. IB after stenting in PAOD cannot be recommended.

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.

Radiation therapy for the treatment of benign vascular, skeletal and soft tissue diseases

The concept of radiation therapy for the treatment of benign diseases refers to the use of moderate to high-energy ionising radiation as part of the treatment of non-malignant, but not necessarily harmless, diseases. The usefulness of radiation therapy, based on the anti-inflammatory properties of ionising radiation, has long been known. Apart from the treatment of intracranial benign tumours, such as meningiomas and neurinomas, the prevention of cardiovascular restenosis or treatment of skeletal degenerative diseases are, without doubt, the main fields of action for radiation therapy in benign conditions. Nonetheless, many other non-cancer entities may benefit from ionising radiation therapy treatment. The purpose of this review is to highlight and update indications for treatment with radiation therapy in benign conditions, focusing on skeletal degenerative processes, vascular conditions and soft tissue diseases.

Midterm and long-term results of percutaneous endovascular treatment of venous outflow obstruction after pediatric liver transplantation

PURPOSE

To evaluate retrospectively the midterm and long-term results of percutaneous endovascular treatment of venous outflow obstruction after pediatric liver transplantation.

MATERIALS AND METHODS

During a 9-year period, 18 children with obstruction of a hepatic vein (HV) or inferior vena cava (IVC) anastomosis underwent percutaneous transluminal angioplasty (PTA) with balloon dilation or stent placement in case of PTA failure after liver transplantation. Patients' body weights ranged from 7.7 kg to 42.6 kg (mean, 18.8 kg +/- 9). Potential predictors of patency were compared between balloon dilation and stent placement groups.

RESULTS

Forty-two procedures were performed (range, 1-11 per patient; mean, 2). Technical and initial clinical success were achieved in all cases. Major complications included one case of pulmonary artery stent embolization and one case of hemothorax. Three children (25%) with HV obstruction were treated with PTA and nine (75%) were treated with stent placement. Three children with IVC obstruction (75%) were treated with PTA and one (25%) was treated with a stent. There were two children with simultaneous obstruction at the HV and IVC; one was treated with PTA and the other with a stent. Cases of isolated HV stenosis have a higher probability of patency with balloon-expandable stent treatment compared with balloon dilation (P < .05). Follow-up time ranged from 7 days to 9 years (mean, 42 months +/- 31), and the primary assisted patency rate was 100% when stent placement was performed among the first three procedures.

CONCLUSIONS

In cases of venous outflow obstruction resulting from HV and/or IVC lesions after pediatric liver transplantation, percutaneous endovascular treatment with balloon dilation or stent placement is a safe and effective alternative treatment that results in long-term patency.

High-Dose-Rate Endobronchial Brachytherapy for Recurrent Airway Obstruction From Hyperplastic Granulation Tissue

PURPOSE

Benign endobronchial granulation tissue causes airway obstruction in up to 20% of patients after lung transplantation or stent placement. High-dose-rate endobronchial brachytherapy (HDR-EB) has been successful in some cases refractory to standard bronchoscopic interventions.

METHODS AND MATERIALS

Between September 2004 and May 2005, 8 patients with refractory benign airway obstruction were treated with HDR-EB, using one to two fractions of Ir-192 prescribed to 7.1 Gy at a radius of 1 cm. Charts were retrospectively reviewed to evaluate subjective clinical response, forced expiratory volume in 1 second (FEV(1)), and frequency of therapeutic bronchoscopies over 6-month periods before and after HDR-EB.

RESULTS

The median follow-up was 14.6 months, and median survival was 10.5 months. The mean number of bronchoscopic interventions improved from 3.1 procedures in the 6-month pretreatment period to 1.8 after HDR-EB. Mean FEV(1) improved from 36% predicted to 46% predicted. Six patients had a good-to-excellent subjective early response, but only one maintained this response beyond 6 months, and this was the only patient treated with HDR-EB within 24 h from the most recent bronchoscopic intervention. Five patients have expired from causes related to their chronic pulmonary disease, including one from hemoptysis resulting from a bronchoarterial fistula.

CONCLUSION

High-dose-rate-EB may be an effective treatment for select patients with refractory hyperplastic granulation tissue causing recurrent airway stenosis. Performing HDR-EB within 24-48 h after excision of obstructive granulation tissue could further improve outcomes. Careful patient selection is important to maximize therapeutic benefit and minimize toxicity. The optimal patient population, dose, and timing of HDR-EB should be investigated prospectively.

Dose perturbation caused by stents: experiments with a model 90Sr/90Y source

PURPOSE

Biological effects of intravascular brachytherapy are very sensitive to discrepancies between the prescription and the applied dose. If brachytherapy is aimed at in-stent restenosis, shielding and shadowing effects of metallic stents may change the dose distribution relative to that produced by the bare source. The development of new generations of stents inspired us to a new experimental study in this field. The effect was studied for 14 stents which we have recently encountered in clinical practice.

METHODS

The model source was a continuous 20-mm column of (90)Sr/(90)Y solution sealed in a 1-mm-I.D. Plexiglas capillary. The dose distribution in the Plexiglas phantom was mapped using GafChromic MD-55-2 film. The stent masses varied from 2.5 to 25 mg; the strut thicknesses, from 0.075 to 0.15 mm; and the atomic numbers of stent materials, from 24 (Cr) to 79 (Au).

RESULTS

Dose perturbations depend on a variety of stent features. Local reduction of the mean dose rates near the reference distance (r(0) = 2 mm) varied from 11% to 47%. No simple correlation was found between these data and stent characteristics, but it seems that the atomic number of the stent material is less important than the strut thickness and mesh density.

CONCLUSION

The results provide a warning that clinical indications for in-stent radiation therapy must always be confronted with another aspect of the patient's history: the kind of implanted stent. Intravascular brachytherapy using pure beta sources may be recommended only for patients "wearing" light, thin-strut stents. The presence of thick-strut stents is a contraindication for this modality, due to excessive dose perturbation.

Performance goals and endpoint assessments for clinical trials of femoropopliteal bare nitinol stents in patients with symptomatic peripheral arterial disease

OBJECTIVE

This analysis proposes safety and performance goals for prospective single-arm trials of bare nitinol stents to treat patients with debilitating claudication associated with femoropopliteal (FP) atherosclerotic lesions.

BACKGROUND

To date there have been no analyses of clinical trials data to set efficacy and safety benchmarks for new bare nitinol stents in the treatment of claudication from FP disease. Industry has been reluctant to sponsor studies of nitinol stents due to logistical barriers.

METHODS

VIVA Physician's, Inc. (VPI) analyzed subject-level data from the PTA control arm of three randomized FDA device trials conducted by industry. Subjects with Rutherford category 2-4 claudication and FP lesion lengths 4-15 cm with 12 month duplex ultrasound (DUS) assessment were identified. These data were combined with the results of a survey of the medical literature (1990-2006) for similar subjects.

RESULTS

Analysis of the industry derived control arm PTA data identified 116 patients (mean lesion length 8.7 cm) with a 12 month DUS defined FP patency of 28%. A similar cohort of 191 patients was identified from the medical literature in which the 12-month vessel patency equaled 37%; from these combined patient cohorts, expected vessel patency for PTA was estimated to equal 33%.

CONCLUSION

Based on the PTA performance efficacy rate of 33% derived from industry clinical trial data and the medical literature, and the requirement that the bare nitinol stent 12-month efficacy performance goal be set to equal twice this rate, the patency efficacy goal equals 66%. Additional information is provided on safety and other reporting standards and stent integrity evaluation for bare metal stents.

Vascular Smooth Muscle Cell Apoptosis Induced by “Supercooling” and Rewarming

PURPOSE

The underlying mechanisms for the reduction in restenosis caused by cryoplasty for peripheral atherosclerotic lesions are not well understood. Because vascular smooth muscle cells (SMCs) are known to play a critical role in restenosis and neointimal hyperplasia, the aim of this study was to determine SMC survival under conditions of "supercooling" and/or rewarming.

MATERIALS AND METHODS

Bovine aortic SMCs were supercooled to -10 degrees C for 0, 60, or 120 seconds with a custom-designed conduction cooling stage and then rewarmed to 37 degrees C in an incubator for 0, 12, or 24 hours. A terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay was used to measure the degree of apoptosis. Activation of Akt (ie, protein kinase B), a key signal protein involved in cell survival, was assessed by Western blot analysis.

RESULTS

An increase in apoptotic SMCs was observed with increasing supercooling and rewarming time. Akt was significantly activated at only the most severe condition (120 seconds of supercooling and 24 hours of rewarming), which showed a 2.03-fold increase compared with the group without rewarming.

CONCLUSIONS

The data suggest that SMC apoptosis occurs with supercooling and rewarming. Protective cell survival mechanisms were activated only late in the rewarming phase. This may partially explain the long-term patency observed with cryoplasty of atherosclerotic peripheral lesions.

Endovascular Brachytherapy for Prophylaxis of Restenosis after Femoropopliteal Angioplasty: Five-year Follow-up—Prospective Randomized Study

PURPOSE

To report the 5-year results from the prospective randomized Vienna-2 trial, which was designed to evaluate the safety and effectiveness of adjunctive endovascular brachytherapy (EBT) compared with no further treatment after successful revascularization in patients with long-segment femoropopliteal lesions.

MATERIALS AND METHODS

Each patient gave written informed consent to participate in the study, which was approved by the hospital's ethics committee. One hundred two patients (men, 53.9%; mean age, 72.1 years +/- 8.7 [standard deviation]; lesion length, 8.1 cm +/- 4.9) underwent percutaneous transluminal angioplasty (PTA) without further stent implantation. Patients were then assigned to either receive EBT (n = 51) by using an iridium 192 source, with a prescribed dose of 12 Gy at 3 mm from the source axis, or no further treatment (n = 51). Radiation was delivered without a centering catheter. Data were analyzed by using a Student t test for continuous values and a chi(2) test to compare categorical values. A Cox proportional hazards regression analysis was performed to evaluate predictors of recurrence at follow-up.

RESULTS

After 6 months, the restenosis rate for the 102 patients with completed 5-year follow-up was significantly reduced for the PTA plus EBT group versus the PTA alone group (29.4% vs 56.9%, P < .05). During follow-up we observed a late catch-up phenomenon, and after 5 years the recurrence rate was comparable in both groups (72.5% vs 72.5%, P > .99). Time to recurrence, however, was significantly delayed in the PTA plus EBT group (17.5 months +/- 14.7 vs 7.4 months +/- 6.8 for the PTA alone group, P < .05).

CONCLUSION

At 5-year follow-up, PTA followed by gamma radiation EBT with a dose of 12 Gy resulted in a delay but not an inhibition of restenosis when compared with that of PTA alone.

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.

Superficial femoral artery: current treatment options

Treatment of the superficial femoral artery (SFA) has been among the least effective of all endovascular procedures in terms of long-term patency. The relatively small vessel lumen, in conjunction with a high plaque burden, slow flow, and a high frequency of primary occlusions, contributes to a considerable rate of acute technical failures. Because of these technical limitations a much effort has been made during the past years. This manuscript should summarize the hopes and limitations of different approaches such as brachytherapy, cutting balloons, stents and stent grafts, drug-eluting stents, and drug-coated balloons.

Randomized blinded clinical trial of intracoronary brachytherapy with 90Sr/Y beta-radiation for the prevention of restenosis after stent implantation in native coronary arteries in diabetic patients

BACKGROUND

We report a double-blind, randomized clinical trial of intracoronary beta-radiation for prevention of restenosis after stent implantation in native coronary de novo lesions in diabetic patients.

METHODS

After successful stent implantation in native coronary de novo lesions, 106 lesions in 89 diabetic patients were randomly allocated to treatment with beta-radiation with 18 Gy at 1 mm vessel depth (n = 53) or placebo treatment (n = 53).

RESULTS

Angiographic analysis at 9 month follow-up revealed a late lumen loss of 0.7+/-0.9 mm in the radiotherapy group versus 1.2+/-0.8 mm in the control group at the injured segment (P = 0.006), 0.9+/-1.0 versus 1.3+/-0.7 mm at the radiated segment (P = 0.02), and 0.9+/-1.0 versus 1.3+/-0.7 mm at the target segment (P = 0.04) (defined as active source length plus 5mm on proximal and distal sites). Binary restenosis rates were significantly lower in the radiation group in all subsegments (injured segment: 10.9 versus 37.3%, P = 0.003; radiated segment: 21.7 versus 49.0%, P = 0.005; target segment: 23.9 versus 49.0%, P = 0.01). Target lesion revascularization for restenosis was required in nine lesions (17.6%) in the radiotherapy group versus 18 (34.0%) in the placebo group (P = 0.05). Late thrombosis occurred in four radiated patients (after premature discontinuation of antiplatelet therapy in all), resulting in a major adverse clinical event rate of 37.2% in the brachytherapy group versus 38.6% in the placebo group (P = ns).

CONCLUSIONS

In diabetic patients with de novo coronary lesions, intracoronary radiation after stent implantation significantly reduced restenosis. However, this clinical benefit was reduced by the frequent occurrence of late thrombosis.

The Use of Femoropopliteal Stent-Grafts for Critical Limb Ischemia

Peripheral vascular disease of the femoropopliteal segment is one of the most common anatomic locations leading to patient symptoms. Traditional open surgical bypass has started to be supplanted by a surge in lower risk endovascular procedures. Though midterm results of endovascular therapy have been acceptable, longer term results, especially in long diffuse disease, appear to be less durable than their surgical alternatives. Recently the Viabahn, a percutaneously placed PTFE stent-graft, has been approved for use in the femoropopliteal artery. Though the majority of the data for this stent-graft has been derived from patients with complex (>10 cm length) lesions, most of the patients have been claudicants. The population with critical limb ischemia is at particularly high risk for cardiovascular mortality and may benefit from this less invasive approach. However, stent-graft utilization is more complex and many variables must be evaluated before and during the procedure to allow for optimal procedural outcomes.

La radiothérapie des affections bénignes : quelles indications huit ans plus tard ?

The authors present an update version of the indications for radiotherapy in the management of benign diseases. This is based on available randomized trials and recent international meetings. Validated indications remain the prevention of resected heterotopic bone ossifications, keloïds scars and pterygium and also treatment of arteriovenous malformations; the place of radiotherapy for malignant exophtalmia is more and more restricted. Randomized trials have demonstrated the efficacy of endobrachytherapy in the prevention of restenosis after angioplasty but the use of embedded stent has replaced this indication. Macular degeneration is no more an indication of radiotherapy. Quality requirements for radiotherapy are identical for benign or malignant indications.

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.