Infrapopliteal Application of Paclitaxel-eluting Stents for Critical Limb Ischemia: Midterm Angiographic and Clinical Results

[Current Strategy in Endovascular Management for Below-the-Knee Arterial Lesions]

The below-the-knee arterial tree is the thinnest of all the leg vessels and is an important path for blood flow to the foot. Hence, lesions including stenosis, especially obstruction, may lead to critical limb ischemia which represents the most severe clinical manifestation of peripheral arterial disease. It is characterized by the presence of ischemic rest pain, ischemic lesions, or gangrene attributable to the objectively proven arterial occlusive disease. Typically, the atherosclerotic disease process involving the below-the-knee arterial tree is diffuse in the majority of patients. The cornerstone of therapy is vascular reconstruction and limb salvage. Revascularization should be attempted whenever technically possible, without delay, in patients presenting critical limb ischemia and when the clinical status is not hopelessly non-ambulatory. Therefore, endovascular treatment can become the gold standard for the full range of patients including below-the-knee, limiting the clinical role of the classically trained surgeons.

10-Year Paclitaxel Dose-Related Outcomes of Drug-Eluting Stents Treated Below the Knee in Patients with Chronic Limb-Threatening Ischemia (The PADI Trial)

Purpose

Recently, two meta-analyses concluded that there appears to be an increased risk of long-term mortality of paclitaxel-coated balloons and stents in the superficial femoral and popliteal artery, and paclitaxel-coated balloons below the knee. In this post hoc study of the PADI Trial, we investigated the long-term safety of first-generation paclitaxel-coated drug-eluting stents (DES) below the knee and the dose–mortality relationships of paclitaxel in patients with chronic limb-threatening ischemia (CLI).

Materials and Methods

The PADI Trial compared paclitaxel-coated DES with percutaneous transluminal angioplasty with bail-out bare-metal stents (PTA ± BMS) in patients with CLI treated below the knee. Follow-up was extended to 10 years after the first inclusion, and survival analyses were performed. In addition, dose-related mortality and dose per patient weight-related mortality relations were examined.

Results

A total of 140 limbs in 137 patients were included in the PADI Trial. Ten years after the first inclusion, 109/137 (79.6%) patients had died. There was no significant difference between mortality in the DES group compared with the PTA ± BMS group (Log-rank p value = 0.12). No specific dose-related mortality (HR 1.00, 95% CI 0.99–1.00, p = 0.99) or dose per weight mortality (HR 1.05, 95% CI 0.93–1.18, p = 0.46) relationships were identified in the Cox-proportional Hazard models or by Kaplan–Meier survival analyses.

Conclusions

There is a poor 10-year survival in both paclitaxel-coated DES and PTA ± BMS in patients with CLI treated below the knee. No dose-related adverse effects of paclitaxel-coated DES were observed in our study of patients with CLI treated below the knee.

Level of Evidence

The PADI Trial: level 1, randomized clinical trial

Electronic supplementary material

The online version of this article (10.1007/s00270-020-02602-6) contains supplementary material, which is available to authorized users.

Balloon Angioplasty of Infrapopliteal Arteries: A Systematic Review and Proposed Algorithm for Optimal Endovascular Therapy

Endovascular revascularization has been increasingly utilized to treat patients with chronic limb-threatening ischemia (CLTI), particularly atherosclerotic disease in the infrapopliteal arteries. Lesions of the infrapopliteal arteries are the result of 2 different etiologies: medial calcification and intimal atheromatous plaque. Although several devices are available for endovascular treatment of infrapopliteal lesions, balloon angioplasty still comprises the mainstay of therapy due to a lack of purpose-built devices. The mechanism of balloon angioplasty consists of adventitial stretching, medial necrosis, and dissection or plaque fracture. In many cases, the diffuse nature of infrapopliteal disease and plaque complexity may lead to dissection, recoil, and early restenosis. Optimal balloon angioplasty requires careful attention to assessment of vessel calcification, appropriate vessel sizing, and the use of long balloons with prolonged inflation times, as outlined in a treatment algorithm based on this systematic review. Further development of specific devices for this arterial segment are warranted, including devices for preventing recoil (eg, dedicated atherectomy devices), treating dissections (eg, tacks, stents), and preventing neointimal hyperplasia (eg, novel drug delivery techniques and drug-eluting stents). Further understanding of infrapopliteal disease, along with the development of new technologies, will help optimize the durability of endovascular interventions and ultimately improve the limb-related outcomes of patients with CLTI.

The use of drug-eluting stents in infrapopliteal arteries: an updated systematic review and meta-analysis of randomized trials

INTRODUCTION

Endovascular treatment below-the-knee is safe and effective but limited by poor patency. Coronary drug-eluting stents (DES) may play a role in providing mechanical scaffolding and deliver anti-proliferative drug to the site of vascular barotrauma to reduce the incidence of restenosis. Our aim was to evaluate and compare the use of contemporary DES with standard endovascular-therapies for atherosclerotic disease of infrapopliteal arteries.

EVIDENCE ACQUISITION

We performed a meta-analysis of randomized controlled trials comparing DES with conventional treatment for symptomatic peripheral artery disease (search date 30 August 2017). The primary endpoint was primary patency. Secondary endpoints were freedom from target lesion revascularization (TLR), major amputation, sustained Rutherford class improvement and mortality.

EVIDENCE SYNTHESIS

We identified 7 trials enrolling 801 randomly assigned patients (392 DES, 409 control). At the median follow-up of 12-months DES improved rates of primary patency (OR 3.49, 95%CI 2.38-5.12, I2=0%, P<0.00001), freedom from TLR (OR 2.19, 95%CI 1.30-3.69, I2=38%, P=0.003), major amputation (OR 0.56, 95%CI 0.31-0.99, I2=0%, P=0.049), and Rutherford class improvement (OR 1.62, 95%CI 1.01-2.59, I2=65%, P=0.046), but not mortality (OR 1.05, 95%CI 0.68-1.62; I2 =0%, P=0.91) compared to control. Subgroup analysis of primary patency favoured DES coated in sirolimus analogues compared to paclitaxel (Test for subgroup differences, Chi2=6.51, df=1, P=0.01, I2=84.6%).

CONCLUSIONS

At midterm follow-up DES significantly improved rates of primary patency, re-intervention, Rutherford class improvement and major amputation for the treatment of atherosclerotic disease of infrapopliteal arteries compared to control therapy, with no effect on patient survival. Stents coated in sirolimus analogues were more effective than paclitaxel.

Treatment of infrapopliteal post-PTA dissection with tack implants: 12-month results from the TOBA-BTK study

OBJECTIVES

The Tack implant is designed for focal, minimal metal management of dissections. This study evaluated Tacks for treating postpercutaneous transluminal angioplasty (PTA) dissection in patients with below-the-knee (BTK) arterial occlusive disease.

BACKGROUND

PTA is the most commonly used endovascular treatment for patients with occlusive disease of the BTK vessels. Post-PTA dissection is a significant clinical problem that results in poor outcomes, but currently there are limited treatment options for managing dissections.

METHODS

This prospective, single-arm study evaluated patients with CLI and BTK lesions; 11.4% were Rutherford category (RC) 4 and 88.6% were RC 5. BTK occlusive disease was treated with standard PTA and post-PTA dissections were treated with Tack placement. The primary safety endpoint was a composite of major adverse limb events (MALE) and perioperative death (POD) at 30 days. Other endpoints included: device success; procedure success (vessel patency in the absence of MALE); freedom from clinically driven target lesion revascularization (CD-TLR); primary patency; and changes in RC. Data through 12 months are presented.

RESULTS

Thirty-two of 35 (91.4%) patients had post-PTA dissection and successful deployment of Tacks. Procedural success was achieved in 34/35 (97.1%) patients with no MALEs at 30 days. The 12-month patency rate was 78.4% by vessel, 77.4% by patient, and freedom from CD-TLR was 93.5%. Significant (P < .0001) improvement from baseline was observed in RC (75% of patients improved 4 or 5 steps).

CONCLUSION

Tack implant treatment of post-PTA dissection was safe and effective for treatment of BTK dissections and resulted in reasonable 12-month patency and low rates of CD-TLR.

One-Year Outcomes of the Paclitaxel-Eluting, Self-Expanding Stentys Stent System in the Treatment of Infrapopliteal Lesions in Patients With Critical Limb Ischemia

Purpose: To investigate the efficacy of the paclitaxel-coated, self-expanding, nitinol Stentys Stent System in tibioperoneal lesions ≤50 mm long. Methods: The prospective, single-arm, multicenter PES-BTK-70 trial ( ClinicalTrials.gov identifier NCT01630070) evaluated the safety and efficacy of the coronary Stentys Stent System in the treatment of a stenotic or occlusive lesion ≤50 mm long in the tibioperoneal arteries of patients with critical limb ischemia (CLI). Between January 2012 and May 2013, 70 patients (mean age 74.6±9.4 years; 45 men) with CLI [Rutherford category 4 (37, 52.9%) or 5 (33, 47.1%)] received a Stentys drug-eluting stent for the treatment of infrapopliteal stenosis (60, 85.7%) or occlusion (10, 14.3%). The mean lesion length was 17.2 mm (4.0–58.5). The primary outcome measures were primary patency at 6 months (duplex ultrasound) and 12 months (angiography). Secondary outcomes included limb salvage and freedom from target lesion revascularization (TLR). Kaplan-Meier estimates of the outcomes are given with the 95% confidence intervals (CI). Results: Technical and procedure success (<30% residual stenosis without major complications) was achieved in 68 (97.1%) of 70 cases. Primary patency was 87.6% (95% CI 83.5% to 91.7%) at 6 months and 72.6% (95% CI 66.9% to 78.3%) at 1 year. Freedom from TLR was 79.1% at 1 year (95% CI 73.9% to 84.3) and limb salvage was 98.5% (95% CI 97.0 to 100.0). No stent fractures were found by core laboratory review of all follow-up imaging data available up to 12 months. Conclusion: In this study, the self-expanding, nitinol, paclitaxel-eluting, coronary Stentys stent was found to be safe and effective in the below-the-knee region, with results similar to the most recent limus-eluting stent trials.

Everolimus-Eluting Stent for Patients With Critical Limb Ischemia and Infrapopliteal Arterial Occlusive Disease

Background:

Critical limb ischemia (CLI), despite revascularization, may result in minor or major amputations with devastating psychological effects and a negative impact on patient survival. Randomized clinical trials demonstrated that drug-eluting stents improve 1-year primary patency and decrease target lesion revascularization, compared to standard angioplasty and bare-metal stents, in patients with short occlusive below-the-knee lesions.

Objectives:

This prospective clinical study was designed to evaluate if one straight-line flow revascularization to the foot, using Xience-Prime Everolimus-Eluting Stent (EES), is an effective treatment of patients in Rutherford-Becker category 4 to 5 with distal popliteal and proximal tibial arteries long occlusive lesions up to 10 cm.

Methods:

All patients with angiographic documented segment P3 of popliteal artery and proximal tibial arteries stenosis >70%, and lesion length between 20 mm and 100 mm, meeting the inclusion criteria, were included in the Etna Registry. The end points assessed were 1- and 3-year primary patency, major amputation-free survival, target lesion revascularization, and wound healing rates.

Results:

Between June 2011 and April 2014, 122 patients were included in the study, with mean lesion length of 52.7 mm (range: 20-100 mm). The 1- and 3-year primary patency rates were 88.9% and 80.1%, respectively. The survival, major amputation-free survival, and target lesion revascularization rates were 88.1%, 93%, and 91.5% at 1-year and 70.4%, 89.3%, and 85.1% at 3-year follow-up, respectively. Primary patency influenced major amputation rate, which was 60% in patients with no target artery patency versus 5.4% in patients with patency ( P = .022). At 1-year follow-up, 78 (88.6%) of 88 patients improved 1 or more of their Rutherford-Becker category, and 48 (80%) of 69 patients had wound healing.

Conclusions:

The results of our study suggest that a conservative approach, with EES, seems feasible in selected patients with CLI and infrapopliteal artery occlusive disease.

Percutaneous Transluminal Angioplasty and Drug-Eluting Stents for Infrapopliteal Lesions in Critical Limb Ischemia (PADI) Trial

Supplemental Digital Content is available in the text.

Background—

Endovascular infrapopliteal treatment of patients with critical limb ischemia using percutaneous transluminal angioplasty (PTA) and bail-out bare metal stenting (BMS) is hampered by restenosis. In interventional cardiology, drug-eluting stents (DES) have shown better patency rates and are standard practice nowadays. An investigator-initiated, multicenter, randomized trial was conducted to assess whether DES also improve patency and clinical outcome of infrapopliteal lesions.

Methods and Results—

Adults with critical limb ischemia (Rutherford category ≥4) and infrapopliteal lesions were randomized to receive PTA±BMS or DES with paclitaxel. Primary end point was 6-month primary binary patency of treated lesions, defined as ≤50% stenosis on computed tomographic angiography. Stenosis >50%, retreatment, major amputation, and critical limb ischemia–related death were regarded as treatment failure. Severity of failure was assessed with an ordinal score, ranging from vessel stenosis through occlusion to the clinical failures. Seventy-four limbs (73 patients) were treated with DES and 66 limbs (64 patients) received PTA±BMS. Six-month patency rates were 48.0% for DES and 35.1% for PTA±BMS (P=0.096) in the modified-intention-to-treat and 51.9% and 35.1% (P=0.037) in the per-protocol analysis. The ordinal score showed significantly worse treatment failure for PTA±BMS versus DES (P=0.041). The observed major amputation rate remained lower in the DES group until 2 years post-treatment, with a trend toward significance (P=0.066). Less minor amputations occurred after DES until 6 months post-treatment (P=0.03).

Conclusions—

In patients with critical limb ischemia caused by infrapopliteal lesions, DES provide better 6-month patency rates and less amputations after 6 and 12 months compared with PTA±BMS.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00471289.

Systematic Review and Meta-analysis of Randomized Controlled Trials of Paclitaxel-Coated Balloon Angioplasty in the Femoropopliteal Arteries: Role of Paclitaxel Dose and Bioavailability

PURPOSE

To provide a qualitative analysis and quantitative synthesis of randomized controlled trials (RCTs) investigating paclitaxel-coated balloons (PCBs) in the femoropopliteal artery.

METHODS

PubMed, EMBASE, AMED, Scopus, CENTRAL, online content, and abstracts from international meetings were last screened in April 2015 for eligible RCTs using the PRISMA selection process. Risk of bias was assessed using the Cochrane Collaboration's tool, and quality of evidence was evaluated with the GRADE system. Outcome measures included late lumen loss (LLL) at 6 months and event rates of major limb amputations, binary lesion restenosis, and target lesion revascularization (TLR). Pooled treatment effects were analyzed in a random effects model to account for clinical heterogeneity; the outcomes are presented as the rate ratios (RRs) and their 95% confidence intervals (CIs). Extensive meta-regression was performed to analyze potential confounders. The review was registered in the PROSPERO database (CRD42015023938; www.crd.york.ac.uk/PROSPERO).

RESULTS

Eleven RCTs with 1609 subjects (1403 claudicants and 206 patients with critical limb ischemia) with medium-length femoropopliteal lesions (mean range 5.1-11.9 cm) were included. There was consistently high-quality evidence supporting the clear superiority of PCBs in terms of reduced LLL (mean difference -0.89 mm, 95% CI -1.14 to -0.64, p<0.001), less binary restenosis (RR 0.47, 95% CI 0.37 to 0.61, p<0.001), and fewer TLR events (RR 0.33, 95% CI 0.22 to 0.49, p<0.001). Major amputations were rare in both active and control arms (pooled event rate: 0.7%, 95% CI 0.3% to 1.2%). Results were stable across all potential risk modifiers and in the presence of stents as well. There was high-quality evidence that the dose of paclitaxel was related to the magnitude of the treatment effect; standard dose (3.0-μg and 3.5-μg) PCBs were significantly more effective compared with low-dose 2-μg PCB in reducing both restenosis (RR 2.1, 95% CI 1.2 to 3.4, p<0.001) and TLR (RR 2.5, 95% CI 1.9 to 3.8, p<0.001).

CONCLUSION

PCBs reduce by more than half the rates of restenosis and TLR in the femoropopliteal artery regardless of stent placement. Biologic effect size may vary according to paclitaxel bioavailability.

Drug delivering technology for endovascular management of infrainguinal peripheral artery disease

Endovascular intervention has become a well-recognized treatment modality for peripheral artery disease; however, mid- and long-term outcomes have been plagued by limited durability. Plain balloon angioplasty and bare-metal stents have historically suffered from high restenosis rates leading to the need for frequent repeat revascularization procedures. The innovation of locally administered, drug-delivering balloons and stents has been a direct result of technological innovations directed toward prevention and treatment of this limitation. Over the last 5 years, numerous clinical trials investigating the use of drug-coated stents and drug-coated balloons indicate a significant improvement in endovascular treatment durability and outcomes. This review provides an up-to-date assessment of the current evidence for the use of drug-coated stents and drug-coated balloons in the treatment of femoropopliteal and infrapopliteal peripheral artery disease. Additionally, it provides an overview of the development of this technology, highlights landmark ongoing and completed clinical trials, examines evidence to support the use of drug-coated technologies in combination with other modalities, and examines promising new technological developments. Last, it summarizes the challenges and safety concerns that have delayed U.S. Food and Drug Administration approval of these devices.

Percutaneous transluminal angioplasty versus primary stenting in infrapopliteal arterial disease: a meta-analysis of randomized trials

BACKGROUND

Percutaneous transluminal angioplasty (PTA) and primary stenting are commonly used endovascular therapeutic procedures for the treatment of infrapopliteal arterial occlusive disease. However, which procedure is more beneficial for patients with infrapopliteal arterial occlusive disease is unknown.

METHODS AND RESULTS

We performed a meta-analysis, searching PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, ISI Web of Knowledge, and relevant websites without language or publication date restrictions for randomized trials that compared primary stenting with PTA in patients with infrapopliteal arterial occlusive disease. The keywords were "stents," "angioplasty," "infrapopliteal," "tibial arteries," and "below knee." We selected immediate technical success, primary and secondary patency, limb salvage, and patient survival as the outcomes of this meta-analysis. On the basis of the inclusion criteria, we identified six prospective randomized trials. One-year outcomes did not show any significant differences between the PTA and primary stenting groups, respectively: technical success (93.3% vs 96.2%; odds ratio [OR], 0.59; 95% confidence interval [CI], 0.24-1.47; P = .25), primary patency (57.1% vs 65.7%; OR, 0.95; 95% CI, 0.35-2.58; P = .92), secondary patency (73.5% vs 57.6%; OR, 2.08; 95% CI, 0.81-5.34; P = .13), limb salvage (82.2% vs 87.5%; OR, 0.64; 95% CI, 0.29-1.41; P = .27), and patient survival (84.0% vs 87.5%; OR, 0.79; 95% CI, 0.40-1.55; P = .49).

CONCLUSIONS

For infrapopliteal arterial occlusive disease, primary stenting has the same 1-year benefits as PTA. There is insufficient evidence to support the superiority of either method. Primary stenting is associated with a trend toward higher primary patency and lower secondary patency. Further large-scale prospective randomized trials should produce more reliable results.

Paclitaxel: new uses for an old drug

Paclitaxel (Taxol), one of the most important anticancer drugs, has been used for therapy of different types of cancers. Mechanistically, paclitaxel arrests cell cycle and induces cell death by stabilizing microtubules and interfering with microtubule disassembly in cell division. Recently, it has been found that low-dose paclitaxel seems promising in treating non-cancer diseases, such as skin disorders, renal and hepatic fibrosis, inflammation, axon regeneration, limb salvage, and coronary artery restenosis. Future studies need to understand the mechanisms underlying these effects in order to design therapies with specificity.

Meta-analysis of outcomes of endovascular treatment of infrapopliteal occlusive disease with drug-eluting stents

PURPOSE

To review emerging evidence regarding the use of bare metal (BMS) vs. drug-eluting stents (DES) in the treatment of infrapopliteal occlusive disease.

METHODS

A systematic review of the literature was undertaken to identify all studies comparing stent treatments of infragenicular vessels in patients with chronic lower limb ischemia. Validated methods to assess the methodological quality of the included studies were applied. Outcome data were pooled, and combined overall effect sizes were calculated using fixed or random effects models. The search identified 4 randomized clinical trials and 2 observational studies reporting on 544 patients (287 treated with DES and 257 treated with BMS). Data are presented as the odds ratio (OR) with 95% confidence interval (CI) and the number-needed-to-treat (NNT).

RESULTS

Primary patency, freedom from target lesion revascularization, and clinical improvement at 1 year were significantly higher in the DES recipients compared to patients treated with BMS (OR 4.511, 95% CI 2.897 to 7.024, p<0.001, NNT 3.5; OR 3.238, 95% CI 2.019 to 5.192, p<0.001, NNT 6.0; and OR 1.792, 95% CI 1.039 to 3.090, p=0.036, NNT 7.3, respectively). No significant differences in limb salvage and overall survival at 1 year were identified between the groups (OR 2.008, 95% CI 0.722 to 5.585, p=0.181; OR 1.262, 95% CI 0.605 to 2.634, p=0.535, respectively). Sensitivity analyses investigating the potential effects of study design and type of DES on the combined outcome estimates validated the results.

CONCLUSION

Our analysis has demonstrated superior short-term results with DES compared with BMS, expressed by increased patency and freedom from target lesion revascularization. The influence of this finding on clinical surrogate endpoints, such as limb salvage, remains unknown.

Stent outcomes for infrapopliteal arterial occlusive disease

This study aimed to determine if the different stent types used in the treatment of infrapopliteal arterial occlusive disease provide any significant advantage over one another at 6 and 12-month follow-up. Consecutive patients undergoing stenting of infrapopliteal lesions were enrolled into a non-randomised prospective registry and followed-up for 1 year. Outcome measures included binary restenosis, target lesion revascularisation, major amputation, and change in Rutherford-Becker score and ankle-brachial index (ABI).Thirty-three patients were enrolled including four patients with bilateral disease. There were 20 target vessels in the drug-eluting stent (DES) group, 13 target vessels in the balloon-expandable bare metal stent (BE-BMS) group and 14 target vessels in the self expandableb are metal stent (SE-BMS) group. Most of the patients in the study were octogenarians except in the SE-BMS group where the mean age was 73 ± 9 years. At 12 months, seven patients had died (DES = 6, BE-BMS = 1) from cardiac and cancer-related diseases. In-stent and peri-stent binary restenosis were non-statistically different between all three groups. There was a nonstatistically significant trend towards higher target vessel revascularisation in the BE-BMS group. Survival curves in all stent types demonstrated restenosis to occur within the first 6 months post-procedure. There was no significant difference in the change in Rutherford-Becker score or ABI between the groups. No major limb amputations occurred during the 12-month period. In conclusion,we did not detect a significant difference in stent performance between the different stent types used to treat infrapopliteal arterial occlusive disease. The choice of stent did not seem to affect patient survival or major amputation-free survival at 1-year follow-up.

Cost-effectiveness analysis of infrapopliteal drug-eluting stents

INTRODUCTION

There are no cost-utility data about below-the-knee placement of drug-eluting stents. The authors determined the cost-effectiveness of infrapopliteal drug-eluting stents for critical limb ischemia (CLI) treatment.

METHODS

The event-free individual survival outcomes defined by the absence of any major events, including death, major amputation, and target limb repeat procedures, were reconstructed on the basis of two published infrapopliteal series. The first included spot Bail-out use of Sirolimus-eluting stents versus bare metal stents after suboptimal balloon angioplasty (Bail-out SES).The second was full-lesion Primary Everolimus-eluting stenting versus plain balloon angioplasty and bail-out bare metal stenting as necessary (primary EES). The number-needed-to-treat (NNT) to avoid one major event and incremental cost-effectiveness ratios (ICERs) were calculated for a 3-year postprocedural period for both strategies.

RESULTS

Overall event-free survival was significantly improved in both strategies (hazard ratio (HR) [confidence interval (CI)]: 0.68 [0.41-1.12] in Bail-out SES and HR [CI]: 0.53 [0.29-0.99] in Primary EES). Event-free survival gain per patient was 0.89 (range, 0.11-3.0) years in Bail-out SES with an NNT of 4.6 (CI: 2.5-25.6) and a corresponding ICER of 6,518<euro> (range 1,685-10,112<euro>). Survival gain was 0.91 (range 0.25-3.0) years in Primary EES with an NNT of 2.7 (CI: 1.7-5.8) and an ICER of 11,581<euro> (range, 4,945-21,428<euro>) per event-free life-year gained. Two-way sensitivity analysis showed that stented lesion length >10 cm and/or DES list price >1000<euro> were associated with the least economically favorable scenario in both strategies.

CONCLUSIONS

Both strategies of bail-out SES and primary EES placement in the infrapopliteal arteries for CLI treatment exhibit single-digit NNT and relatively low corresponding ICERs.

A prospective randomized multicenter comparison of balloon angioplasty and infrapopliteal stenting with the sirolimus-eluting stent in patients with ischemic peripheral arterial disease: 1-year results from the ACHILLES trial

OBJECTIVES

The study investigated the efficacy and safety of a balloon expandable, sirolimus-eluting stent (SES) in patients with symptomatic infrapopliteal arterial disease.

BACKGROUND

Results of infrapopliteal interventions using balloon angioplasty and/or bare stents are limited by a relatively high restenosis rate, which could be potentially improved by stabilizing the lesion with a SES.

METHODS

Two hundred patients (total lesion length 27 ± 21 mm) were randomized to infrapopliteal SES stenting or percutaneous transluminal balloon angioplasty (PTA). The primary endpoint was 1-year in-segment binary restenosis by quantitative angiography.

RESULTS

Ninety-nine and 101 patients (mean age 73.4 years; 64% diabetics) were randomized to SES and PTA, respectively (8 crossover bailout cases to SES). At 1 year, there were lower angiographic restenosis rates (22.4% vs. 41.9%, p = 0.019), greater vessel patency (75.0% vs. 57.1%, p =0.025), and similar death, repeat revascularization, index-limb amputation rates, and proportions of patients with improved Rutherford class for SES versus PTA.

CONCLUSIONS

SES implantation may offer a promising therapeutic alternative to PTA for treatment of infrapopliteal peripheral arterial disease.

Neo-intimal hyperplasia, diabetes and endovascular injury

Diabetes is a significant major risk factor for peripheral arterial disease (PAD) and critical limb ischaemia (CLI), the latter which is also the most common cause of amputation in these patients. Revascularisation of the lower extremities of such patients is imperative for limb salvage and has become First-line therapy. However, the incidence of restenosis following endovascular stenting is very high and is largely due to neo-intimal hyperplasia (NIH), the regulation of which is for the greater part not understood. This article therefore reviews our understanding on the regulation of NIH following stent-induced vascular injury, and highlights the importance of future studies to investigate whether the profile of vascular progenitor cell differentiation, neo-intimal growth factors and lumen diameters predict the severity of post-stent NIH in the peripheral arteries. Results from future studies will (1) better our understanding of the regulation of NIH in general, (2) determine whether combinations of any of the vascular factors discussed are predictive of the extent of NIH postoperatively, and (3) potentially facilitate future therapeutic targets and/or change preventive strategies.

Below-the-knee drug-eluting stents and drug-coated balloons

Endovascular procedures have evolved to the mainstream treatment of choice for revascularization of infrapopliteal obstructive disease, especially in patients suffering from critical limb ischemia and multiple comorbidities. However, standard balloon angioplasty is limited by the potential of a suboptimal acute outcome due to elastic recoil and/or flow-limiting dissection, followed by neointimal hyperplasia and progressive vascular restenosis even in the case of bare-metal stent use. Drug-eluting stents and drug-coated balloons are emerging endovascular technologies with the promise of significant inhibition of vessel restenosis and improved clinical outcomes. The current review outlines the drug-eluting properties of those instruments and summarizes the currently available clinical data. The authors critically appraise the current status and also provide a glimpse of the near future of endovascular below-the-knee treatments.

Primary everolimus-eluting stenting versus balloon angioplasty with bailout bare metal stenting of long infrapopliteal lesions for treatment of critical limb ischemia

PURPOSE

To report the long-term outcomes of a single-center prospective study investigating primary placement of everolimus-eluting metal stents for recanalization of long infrapopliteal lesions compared to a matched historical control group treated with plain balloon angioplasty and provisional placement of bare metal stents in a bailout manner.

METHODS

The study included 81 patients (63 men; mean age 71 years, range 45-85) suffering from critical limb ischemia (CLI) and angiographically proven long-segment (at least 1 lesion >4.5 cm) de novo infrapopliteal artery disease who underwent below-the-knee revascularization with either primary placement of everolimus-eluting stents (n = 47, 51 limbs, 102 lesions) or angioplasty and bailout bare metal stenting (n = 34, 36 limbs, 72 lesions). Clinical and angiographic follow-up was collected at regular time intervals. Primary clinical and angiographic endpoints included patient survival, major amputation-free survival, angiographic primary patency, angiographic binary restenosis (>50%), and overall event-free survival. Results were stratified according to endovascular treatment received. Multivariable Cox proportional hazards regression analysis was applied to adjust for confounding factors of heterogeneity.

RESULTS

Baseline demographics were well matched. No significant differences were identified between the 2 groups with regard to overall 3-year patient survival (82.2% versus 65.7%; p = 0.90) and amputation-free survival (77.1% versus 86.9%; p = 0.20). Up to 3 years, lesions fully covered with everolimus-eluting stents were associated with significantly higher primary patency [hazard ratio (HR) 7.98, 95% CI 3.69 to 17.25, p < 0.0001], reduced binary restenosis (HR 2.94, 95% CI 1.74 to 4.99, p < 0.0001), and improved overall event-free survival (HR 2.19, 95% CI 1.16 to 4.13, p = 0.015) versus the matched historical control group.

CONCLUSION

Primary infrapopliteal everolimus-eluting stenting for CLI treatment significantly inhibits restenosis and improves long-term angiographic patency and overall patient event-free survival compared to balloon angioplasty and bailout bare metal stenting.

Cryoplasty versus conventional balloon angioplasty of the femoropopliteal artery in diabetic patients: long-term results from a prospective randomized single-center controlled trial

The purpose of this study was to investigate the immediate and long-term results of cryoplasty versus conventional balloon angioplasty in the femoropopliteal artery of diabetic patients. Fifty diabetic patients (41 men, mean age 68 years) were randomized to cryoplasty (group CRYO; 24 patients with 31 lesions) or conventional balloon angioplasty (group COBA; 26 patients with 34 lesions) of the femoropopliteal artery. Technical success was defined as <30% residual stenosis without any adjunctive stenting. Primary end points included technical success, primary patency, binary in-lesion restenosis (>50%), and freedom from target lesion recanalization. Cox proportional hazards regression analysis was performed to adjust for confounding factors of heterogeneity. In total, 61.3% (19 of 31) in group CRYO and 52.9% (18 of 34) in group COBA were de novo lesions. More than 70% of the lesions were Transatlantic Inter-Society Consensus (TASC) B and C in both groups, and 41.4% of the patients in group CRYO and 38.7% in group COBA suffered from critical limb ischemia. Immediate technical success rate was 58.0% in group CRYO versus 64.0% in group COBA (p = 0.29). According to 3-year Kaplan-Meier estimates, there were no significant differences with regard to patient survival (86.8% in group CRYO vs. 87.0% in group COBA, p = 0.54) and limb salvage (95.8 vs. 92.1% in groups CRYO and COBA, respectively, p = 0.60). There was a nonsignificant trend of increased binary restenosis in group CRYO (hazard ratio [HR] 1.3; 95% CI 0.6-2.6, p = 0.45). Primary patency was significantly lower in group CRYO compared with group COBA (HR 2.2; 95% CI 1.1-4.3, p = 0.02). Significantly more repeat intervention events because of recurrent symptoms were required in group CRYO (HR 2.5; 95% CI 1.2-5.3, p = 0.01). Cryoplasty was associated with lower primary patency and more clinically driven repeat procedures after long-term follow-up compared with conventional balloon angioplasty.

Treating the diseased superficial femoral artery

Vascular disease involving the superficial femoral artery (SFA) is common. Once the decision to treat the SFA is made, the benefits and limitations of angioplasty and stents must be applied to each specific patient. Additionally, the potential role of covered stents as well as drug eluting stents must be considered.

[Recanalization of the lower leg: PTA or stent?]

Percutaneous transluminal angioplasty (PTA) and stent placement are currently accepted methods for endovascular treatment of critical limb ischemia, if infragenual vessels are involved. Outcome results in high technical success and satisfactory clinical results for treatment of infrapopliteal lesions with regard to patency rates and amputation-free survival. These treatment modalities are also safe for the patients. The question whether PAT alone or additional stent placement is the better choice, is still unanswered due to limited data.

Restenosis after lower extremity interventions: current status and future directions

The incidence of restenosis after percutaneous peripheral interventions (PPI) varies considerably depending upon the vascular bed but appears to be highest in the femoropopliteal and tibioperoneal arteries. The restenosis process in the periphery does not appear to stop at the 6-month mark, as seen with bare metal stents in the coronary arteries, but continues for a longer time, possibly years, after the intervention. This review evaluates the incidence of restenosis following lower extremity arterial interventions and potential drugs or devices that could alter this process, including nonpharmacological (stents, cryoplasty, Cutting Balloon angioplasty, atherectomy, brachytherapy, and photodynamic therapy) and pharmacological (systemic and direct drug delivery) approaches. A global strategy to achieve optimal outcome with PPI is offered: (1) obtain excellent acute angiographic results with less dissection and recoil, (2) protect the distal tibial vascular bed, and (3) reduce smooth muscle cell proliferation with pharmacological intervention.

Infrapopliteal application of sirolimus-eluting versus bare metal stents for critical limb ischemia: analysis of long-term angiographic and clinical outcome

PURPOSE

To present the 3-year angiographic and clinical results of a prospective registry investigating the performance of sirolimus-eluting stents (SESs) versus bare metal stents (BMSs) for critical limb ischemia (CLI) treatment.

MATERIALS AND METHODS

A single-center double-arm prospective registry included patients with CLI who underwent infrapopliteal revascularization with angioplasty and "bailout" use of an SES or BMS. Clinical and angiographic follow-up was scheduled at regular time intervals. Primary clinical and angiographic endpoints included mortality, limb salvage, primary patency, binary angiographic restenosis (ie, >50%), and clinically driven repeat intervention-free survival. Results were stratified according to stent type, and cumulative proportion outcomes were determined by Kaplan-Meier plots. Multivariable Cox proportional-hazards regression analysis was applied to adjust for confounding factors of heterogeneity.

RESULTS

In total, 103 patients were included in the analysis; 41 (75.6% with diabetes) were treated with a BMS (47 limbs; 77 lesions) and 62 (87.1% with diabetes) with an SES (75 limbs; 153 lesions). At 3 years, SES-treated lesions were associated with significantly better primary patency (hazard ratio [HR], 4.81; 95% CI, 2.91-7.94; P < .001), reduced binary restenosis (HR, 0.38; 95% CI, 0.25-0.58; P < .001), and better repeat intervention-free survival (HR, 2.56; 95% CI, 1.30-5.00; P = .006) versus BMS-treated ones. No significant differences were identified between SESs and BMSs with regard to overall 3-year patient mortality (29.3% vs 32.0%; P = .205) and limb salvage (80.3% vs 82.0%; P = .507).

CONCLUSIONS

Infrapopliteal application of SESs for CLI significantly improves angiographic long-term patency and reduces infrapopliteal vascular restenosis versus BMSs, thereby lessening the rate of clinically driven repeat interventions.

Current literature for evidence-based infrainguinal endovascular treatment

With the proliferation of devices and techniques for lower extremity endovascular revascularization, treatment decisions become increasingly difficult as only limited experience with these new technologies is available for review. This monograph attempts to define the current state of the literature available to guide endovascular treatment of superficial artery disease, and to provide a baseline for future studies.

Incidence, anatomical location, and clinical significance of compressions and fractures in infrapopliteal balloon-expandable metal stents

PURPOSE

To investigate the incidence, anatomical location, and clinical impact of fractures and/or compression of infrapopliteal balloon-expandable metal stents implanted for critical limb ischemia (CLI) treatment.

METHODS

This prospective study included 63 CLI patients (45 men; mean age 71.3+/-9.5 years) who had been treated with infrapopliteal angioplasty and stent placement for 191 lesions in 84 limbs. In all, 369 stents (296 stainless steel and 73 cobalt-chromium alloy) were implanted; 239 were placed overlapping in tandem lesions. Mean length of the overall stented segment was 4.4+/-6.3 cm (range 1.6-14.0). Stents were located in the tibioperoneal (n = 34), anterior tibial (n = 195), posterior tibial (n = 63), and peroneal (n = 77) arteries. Follow-up consisted of digital subtraction angiography and infrapopliteal radiography imaging at 2 different angles. Evaluation of stents for the presence of fracture and/or compression was done after digital processing at the highest possible magnification. Stent fractures were defined according to published standards, whereas compression was classified as severe shape alteration and/or collapse of the stent mesh. Angiographic restenosis was based on a 50% threshold.

RESULTS

Mean follow-up was 15+/-11 months (range 6-60). Image analysis detected 1 (0.3%) severe stent fracture (complete separation and misalignment of stent struts) and 11 (3.0%) stent compressions. Infrapopliteal stent fracture and compressions were associated with increased artery restenosis [100% (12/12) versus 47.3% (169/357), p<0.001] and an increased rate of clinical deterioration and clinically-driven reinterventions [41.7% (5/12 limbs) versus 19.4% (14/72 limbs), p = 0.04]. The single fracture and most of the compressions were located in the distal third of the anterior tibial artery.

CONCLUSION

Stent fractures and compressions of infrapopliteal balloon-expandable metal stents are infrequent. However, they may be related to increased restenosis.

Current status of infrapopliteal artery stenting in patients with critical limb ischemia

Due to the fear that early thrombosis and late luminal loss resulting from intimal hyperplasia might impede sustained patency of small-caliber arteries, such as those of the infrapopliteal bed, stent implantation in below-knee vessels remains controversial and is generally reserved for cases with a suboptimal outcome after percutaneous transluminal angioplasty (i.e. > 50% residual stenosis, flow-limiting dissection). Although evidence starts to build, favoring the use of stenting in the tibial area, results of well-conducted randomized controlled trials have to be awaited to change this strategy. Because of diameter similarities with coronary arteries, the first stents applied in the infrapopliteal vessels were all coronary devices. Once the feasibility of the stenting approach with these coronary products was shown, device manufacturers started to develop a dedicated infrapopliteal product range. To date, a broad spectrum of stent types has been used and investigated for the given indication. This article overviews the available literature and results of different balloon-expandable (bare metal, passive coated, drug eluting), self-expanding and absorbable stent types available for below-the-knee application and gives recommendations for future device technology advancements.