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

Drug-Coated Balloon Treatment for Femoropopliteal Artery Disease: The IN.PACT Global Study De Novo In-Stent Restenosis Imaging Cohort

OBJECTIVES

This study sought to evaluate the safety and effectiveness of a paclitaxel-coated drug-coated balloon (DCB) for the treatment of patients with de novo in-stent restenosis (ISR).

BACKGROUND

Treatment of patients with ISR remains a challenge. Current strategies are plagued by high rates of recurrent restenosis and need for reintervention. The best intervention for ISR remains to be elucidated.

METHODS

The IN.PACT Global study is an independently adjudicated multicenter, prospective, single-arm study that enrolled 1,535 subjects with symptomatic atherosclerotic disease of the superficial femoral and/or popliteal arteries, including de novo ISR lesions. Patients enrolled in the pre-specified ISR imaging cohort were evaluated for vessel patency and reintervention within the 12-month follow-up period.

RESULTS

A total of 131 subjects with 149 ISR lesions were included for analysis. The mean age of the cohort was 67.8 years. Mean lesion length was 17.17 ± 10.47 cm, including 34.0% total occlusions and 59.1% calcified lesions. The 12-month Kaplan-Meier estimate of primary patency was 88.7%. The rate of clinically driven target lesion revascularization (CD TLR) at 12 months was 7.3%. The primary safety outcome, a composite of freedom from device- and procedure-related mortality through 30 days and freedom from major target limb amputation and CD TLR within 12 months, was 92.7%. There were no major target limb amputations, no deaths, and a low (0.8%) thrombosis rate.

CONCLUSIONS

Results from the ISR imaging cohort demonstrate high patency and a low rate of CD TLR at 12 months. These data confirm the safety and effectiveness of the IN.PACT Admiral DCB (Medtronic, Dublin, Ireland) in complex femoropopliteal lesions, including this challenging subset.

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.

Critical appraisal of paclitaxel balloon angioplasty for femoral-popliteal arterial disease

Peripheral arterial disease, particularly critical limb ischemia, is an area with urgent need for optimized therapies because, to date, vascular interventions often have limited life spans. In spite of initial encouraging technical success after femoropopliteal percutaneous transluminal angioplasty or stenting, postprocedural restenosis remains the major problem. The challenging idea behind the drug-coated balloon (DCB) concept is the biological modification of the injury response after balloon dilatation. Antiproliferative drugs administered via DCBs or drug-eluting stents are able to suppress neointimal hyperplasia, the main cause of restenosis. This article reviews the results of DCB treatments of femoropopliteal and infrapopliteal lesions in comparison to standard angioplasty with uncoated balloons. A systematic literature search was performed in 1) medical journals (ie, MEDLINE), 2) international registers for clinical studies (ie, www.clinicaltrials.gov), and 3) abstracts of scientific sessions. Several controlled randomized trials with follow-up periods of up to 5 years demonstrated the efficacy of paclitaxel –DCB technology. However, calcified lesions seem to affect the efficacy of DCB. Combinations of preconditioning methods with DCBs showed promising results. Although the mechanical abrasion of calcium via atherectomy or laser ablation showed favorable periprocedural results, the long-term impact on restenosis and clinical outcome has to be demonstrated. Major advantages of the DCBs are the rapid delivery of drug at uniform concentrations with a single dose, their efficacy in areas wherein stents have been contraindicated until now (ie, bifurcation, ostial lesions), and in leaving no stent scaffold behind. Reinterventions are easier to perform because DCBs leave no metal behind. Various combinations of DCBs with other treatment modalities may prove to be viable options in future. The follow-up results of clinical studies will evaluate the long-term impact of DCBs.

Drug-Eluting Stent vs Percutaneous Transluminal Angioplasty for Treatment of Femoropopliteal In-Stent Restenosis: Results From a Retrospective 1-Year Multicenter Study

PURPOSE

To compare drug-eluting stent (DES) implantation with percutaneous transluminal angioplasty (PTA) in the treatment of femoropopliteal in-stent restenosis (ISR).

METHODS

A comparison was performed of data from 112 ZEPHYR registry patients (mean age 74±9 years; 60 men) with 119 femoropopliteal ISR lesions treated with a drug-eluting stent (Zilver PTX) with historical data from 116 patients (mean age 72±8 years; 83 men) with 133 lesions treated with PTA. The patients were stratified for analysis by lesions with (101/252, 40%) and without (n=151) in-stent occlusion. The primary outcome measure was the 1-year incidence of recurrent restenosis; the secondary outcome was major adverse limb events (MALE). Multivariate logistic regression analysis was performed to look for any independent association of DES implantation with 1-year recurrent restenosis in the respective subgroups; results are presented as the odds ratio (OR) and 95% confidence interval (CI).

RESULTS

In the subgroup without in-stent occlusion, there was no significant difference between DES and PTA in the 1-year incidence of recurrent restenosis (40.5% vs 45.7%, p=0.583, respectively) or MALE (27.8% vs 20.7%, p=0.322, respectively). However, in the subgroup with in-stent occlusion, DES implantation was associated with significantly lower incidences of recurrent restenosis (44.1% vs 90.3% for PTA, p<0.001) and MALE (25.5% vs 53.6% for PTA, p<0.001). Multivariate analysis confirmed that DES implantation had a significant independent negative association with the risk of recurrent restenosis in the subgroup with occlusion (OR 0.2, 95% CI 0.1 to 0.6, p=0.006).

CONCLUSION

DES implantation may be more effective than PTA in the management of femoropopliteal ISR with occlusion, but equally effective to PTA in nonocclusive ISR lesions. These results require confirmation in prospective randomized studies.

Evaluation of (188)Re-labeled NGR-VEGI protein for radioimaging and radiotherapy in mice bearing human fibrosarcoma HT-1080 xenografts

Vascular endothelial growth inhibitor (VEGI) is an anti-angiogenic protein, which includes three isoforms: VEGI-174, VEGI-192, and VEGI-251. The NGR (asparagine-glycine-arginine)-containing peptides can specifically bind to CD13 (Aminopeptidase N) receptor which is overexpressed in angiogenic blood vessels and tumor cells. In this study, a novel NGR-VEGI fusion protein was prepared and labeled with (188)Re for radioimaging and radiotherapy in mice bearing human fibrosarcoma HT-1080 xenografts. Single photon emission computerized tomography (SPECT) imaging results revealed that (188)Re-NGR-VEGI exhibits good tumor-to-background contrast in CD13-positive HT-1080 tumor xenografts. The CD13 specificity of (188)Re-NGR-VEGI was further verified by significant reduction of tumor uptake in HT-1080 tumor xenografts with co-injection of the non-radiolabeled NGR-VEGI protein. The biodistribution results demonstrated good tumor-to-muscle ratio (4.98 ± 0.25) of (188)Re-NGR-VEGI at 24 h, which is consistent with the results from SPECT imaging. For radiotherapy, 18.5 MBq of (188)Re-NGR-VEGI showed excellent tumor inhibition effect in HT-1080 tumor xenografts with no observable toxicity, which was confirmed by the tumor size change and hematoxylin and eosin (H&E) staining of major mouse organs. In conclusion, these data demonstrated that (188)Re-NGR-VEGI has the potential as a theranostic agent for CD13-targeted tumor imaging and therapy.

Outcomes of Zilver PTX stent implantation for the treatment of complex femoropopliteal artery disease

The purpose of this study was to evaluate the efficacy of Zilver PTX, the first drug-eluting stent, in patients with complex femoropopliteal (FP) artery disease. Between July 2012 and March 2013, 60 consecutive patients (39 males; mean age: 72.5 ± 8.6 years) with complex risk factors including TASC II C/D lesions, in-stent restenosis (ISR) and/or on haemodialysis underwent successful Zilver PTX implantation for symptomatic FP artery disease. The primary outcome was primary patency, which was defined as freedom from restenosis at 12 months, as verified by duplex ultrasound. Secondary outcomes included the technical success rate, the freedom from target lesion revascularisation (TLR) rate and the amputation-free survival (AFS) rate. The average follow-up period was 13.2 ± 5.3 months. 62 % of the patients had TASC II C/D lesions, 35.0 % experienced ISR, and 41.6 % were on haemodialysis. The mean lesion length was 188 ± 96 mm. The technical success rate was 98.3 %. The primary patency rate was 50.2 %, the freedom from clinically driven TLR rate was 68.6 %, and the AFS rate was 83.2 % at 12 months. In conclusion, Zilver PTX stent implantation for complex FP artery disease did not affect long-term durability.

Drug-eluting balloons for femoropopliteal lesions show better performance in de novo stenosis or occlusion than in restenosis

OBJECTIVE

Although drug-eluting balloons (DEBs) have shown promising results treating de novo (DN) atherosclerotic lesions and appear to have been widely adopted in Europe, their long-term efficacy in the broad spectrum of femoropopliteal restenosis (RE) remains to be proven. The purpose of the study was to assess the efficacy of paclitaxel-DEBs in restenotic (stented and nonstented) vs DN stenotic femoropopliteal arteries.

METHODS

The study prospectively enrolled 100 patients undergoing femoropopliteal endovascular intervention by DEB for RE or DN stenosis. Patients who received additive atherectomy were excluded. The primary end point was the primary patency (PP) rate at 12 months. Secondary end points were sustained clinical improvement and clinically driven target lesion revascularization.

RESULTS

DEBs were used to treat 105 limbs for intermittent claudication (82 [78%]) or critical limb ischemia (23 [22%]) in 100 patients. Of these, 111 lesions were DN stenosis (46 [41%]) or RE (65 [59%]). The overall PP was 86% at 6 months and 74% at 12 months. PP of DN stenosis was higher at 6 months (93% vs 81%) and was significantly (P = .021) better than RE at 12 months (85% vs 68%). Sustained clinical improvement based on Rutherford classification was significant in both groups (P < .001). Target lesion revascularization was significantly lower in DN stenosis compared with RE at 12 months (15% vs 32%; P = .021).

CONCLUSIONS

DEB angioplasty is an effective therapy for DN femoropopliteal lesions. The results of DEB angioplasty for RE are inferior compared with DN stenosis after 12 months. Nevertheless, results of DEB angioplasty for RE seem comparable with technically more demanding literature-derived strategies.

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.

Management of subclavian artery in-stent restenosis

Stenotic and occlusive diseases of the subclavian and brachiocephalic arteries can cause a significant morbidity as it can lead to symptomatic ischemia affecting the upper extremities, brain and, in some cases, the heart. An endovascular approach with primary stenting or provisional stenting has become the primary modality of revascularization of subclavian artery stenosis. In-stent restenosis can be treated with percutaneous transluminal angioplasty or repeat stenting and although stents offer superior long-term patency over balloon angioplasty alone for de novo lesions, there are no data regarding primary versus provisional stenting in subclavian in-stent restenosis. Here we describe a case of subclavian in-stent restenosis treated with just balloon angioplasty and demonstrate that provisional stenting with angioplasty alone when the percutaneous transluminal angioplasty results are excellent is a reasonable alternative to primary stent placement for subclavian in-stent restenosis.