Stent placement in the superficial femoral and proximal popliteal arteries with the innova self-expanding bare metal stent system

Endovascular Therapy with Interwoven Nitinol Stent Placement after Predilation for Heavily Calcified Femoropopliteal Artery Disease: Results of the BURDOCK Study

PURPOSE

To investigate the 1-year and 2-year clinical outcomes of interwoven stent (IWS) implantation for symptomatic femoropopliteal arterial disease with calcification.

MATERIAL AND METHODS

This prospective multicenter study evaluated 308 limbs (63% with the peripheral arterial calcium scoring system 3 and 4 severe calcification and 87% with ≥180° calcification on intravascular ultrasound) of 299 patients (diabetes in 66.9%, chronic renal failure in 52.8%, and dialysis in 49.2%) who underwent IWS (Supera; Abbott, Abbott Park, Illinois) implantation after sufficient predilation (residual stenosis < 30%) for calcified femoropopliteal lesions. The primary outcome measure was primary patency (freedom from restenosis) at 1 and 2 years, whereas the secondary outcome measure included freedom from clinically driven target lesion revascularization (CD-TLR). Clinical parameters associated with loss of patency were explored.

RESULTS

Kaplan-Meier analysis showed that primary patency was 88.2% (95% confidence interval [CI], 84.5%-92.1%) at 1 year and 80.8% (95% CI, 76.1%-85.8%) at 2 years. The CD-TLR-free rate was 96.5% and 94.8% at 1 and 2 years, respectively. The characteristics associated with loss of patency were restenotic lesion with and without stent implantation (adjusted hazard ratio, 1.96 and 2.40; P = .047 and .041, respectively), chronic total occlusion (adjusted hazard ratio, 1.88; P = .022), and popliteal involvement (adjusted hazard ratio, 2.60; P = .002).

CONCLUSIONS

The implantation of IWS after sufficient predilation for calcified femoropopliteal atherosclerotic disease demonstrated clinically acceptable primary patency.

A method of assessing peripheral stent abrasiveness under cyclic deformations experienced during limb movement

Poor outcomes of peripheral arterial disease stenting are often attributed to the inability of stents to accommodate the complex biomechanics of the flexed lower limb. Abrasion damage caused by rubbing of the stent against the artery wall during limb movement plays a significant role in reconstruction failure but has not been characterized. Our goals were to develop a method of assessing the abrasiveness of peripheral nitinol stents and apply it to several commercial devices. Misago, AbsolutePro, Innova, Zilver, SmartControl, SmartFlex, and Supera stents were deployed inside electrospun nanofibrillar tubes with femoropopliteal artery-mimicking mechanical properties and subjected to cyclic axial compression (25%), bending (90°), and torsion (26°/cm) equivalent to five life-years of severe limb flexions. Abrasion was assessed using an abrasion damage score (ADS, range 1-7) for each deformation mode. Misago produced the least abrasion and no stent fractures (ADS 3). Innova caused small abrasion under compression and torsion but large damage under bending (ADS 7). Supera performed well under bending and compression but caused damage under torsion (ADS 8). AbsolutePro produced significant abrasion under bending and compression but less damage under torsion (ADS 12). Zilver fractured under all three deformations and severely abraded the tube under bending and compression (ADS 15). SmartControl and SmartFlex fractured under all three deformations and produced significant abrasion due to strut penetration (ADS 20 and 21). ADS strongly correlated with clinical 12-month primary patency and target lesion revascularization rates, and the described method of assessing peripheral stent abrasiveness can guide device selection and development. STATEMENT OF SIGNIFICANCE: Poor outcomes of peripheral arterial disease stenting are related to the inability of stents to accommodate the complex biomechanics of the flexed lower limb. Abrasion damage caused by rubbing of the stent against the artery wall during limb movement plays a significant role in reconstruction failure but has not been characterized. Our study presents the first attempt at assessing peripheral stent abrasiveness, and the proposed method is applied to compare the abrasion damage caused by Misago, AbsolutePro, Innova, Zilver, SmartControl, SmartFlex, and Supera peripheral stents using artery-mimicking synthetic tubes and cyclic deformations equivalent to five life-years of severe limb flexions. The abrasion damage caused by stents strongly correlates with their clinical 12-month primary patency and target lesion revascularization rates, and the described methodology can be used as a cost-effective and controlled way of assessing stent performance, which can guide device selection and development.

A review on femoropopliteal arterial deformation during daily lives and nickel-titanium stent properties

The increasing number of studies on the behaviour of stent placement in recent decades provides a clear understanding of peripheral artery disease (PAD). The severe mechanical loads (axial tension and compression, bending, radial compression and torsion) deformation of the femoropopliteal artery (FPA) is responsible for the highest failure rate of permanent nickel-titanium (Nitinol) stents. Therefore, the purpose of this article is to review research papers that examined the deformation of the natural load environment of FPA, the properties of Nitinol and mechanical considerations. In conclusion, a better understanding of mechanical behaviour for FPA Nitinol stents contributes to increased mechanical performance and fatigue-life.

Three-Year Clinical Outcomes of the Innova™ Self-Expanding Nitinol Stent for the Treatment of Femoropopliteal Lesions

PURPOSE

To report the 3-year results of Innova™ stent implantation for the treatment of femoropopliteal (FP) lesions in a real-world setting.

METHODS

This single-arm, retrospective, multicenter clinical study analyzed 481 lesions from 453 consecutive patients with symptomatic peripheral artery diseases (Rutherford category 1-6) who underwent endovascular therapy with implantation of Innova™ self-expanding nitinol stent for FP lesions. The primary outcome measure was the 3-year restenosis rate based on doppler-ultrasound or angiographic criteria. The secondary outcome measures included the rates of 3-year major amputation and major adverse limb events.

RESULTS

Restenosis following Innova™ implantation was found in 61% of the cases at 3 years. At the end of 3 years, the rates of major amputations and major adverse limb events were 3 and 31%, respectively. In cases free from restenosis at 1 year, no predictive factors for restenosis at 3 years could be determined.

CONCLUSION

The present study demonstrated mid-term clinical outcomes after Innova™ stent implantation for the treatment of FP lesions in a real-world population. The Innova™ stent demonstrated acceptable clinical outcomes in a real-world setting.

An Update on Drug-eluting Technology in Peripheral Arteries to Treat Peripheral Arterial Disease

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Effect of Target Lesion Revascularization on Restenosis Lesions of the Superficial Femoral Artery without Recurred Symptoms after Endovascular Therapy

Aim: This study aims to elucidate the effects of early application of target lesion revascularization (TLR) to restenosis lesions of the superficial femoral artery (SFA) without recurrence of symptoms. Despite recent improvements in endovascular therapy (EVT) for the SFA, restenosis remains to be a problem. However, restenosis is not always associated with the recurrence of limb symptoms. Although early application of TLR is not generally approved for restenosis lesions of the SFA without recurred symptoms, it is expected to contribute to long-term patency and other favorable outcomes. Nonetheless, its effectiveness remains to be determined.

Methods: We retrospectively analyzed 616 patients who developed restenosis after undergoing femoro-popliteal EVT for claudication (Rutherford category 1 to 3) due to de novo femoro-popliteal lesions between January 2010 and December 2016 at 11 centers in Japan. Recurred symptoms were defined as symptoms of the same or higher Rutherford categories than those immediately before the initial EVT.

Results: Of the patients, 291 (47 %) lacked recurred symptoms; 69 (24 %) underwent TLR for restenosis. After propensity matching, the risk of occlusion was determined to be not significantly different between the TLR and observation groups; the 3-year occlusion-free rate was 68 % and 62 %, respectively (P=0.84). The risk of recurring symptoms, critical limb ischemia, and all-cause death was also found to be comparable between groups. The incidence of target vessel revascularization was significantly higher in the TLR than in the observation group (1.55 [95 % confidence interval: 1.25–1.93] vs. 0.59 [0.41–0.85] per 3 person-years).

Conclusions: In patients with SFA restenosis without recurred symptoms, early application of TLR showed no advantages.

Effectiveness and Safety of a Paclitaxel-Eluting Stent for Superficial Femoral Artery Lesions up to 190 mm: One-Year Outcomes of the Single-Arm IMPERIAL Long Lesion Substudy of the Eluvia Drug-Eluting Stent

Purpose: To report the clinical effect of a drug-eluting stent on femoropopliteal occlusive disease in patients with long lesions. Materials and Methods: The global IMPERIAL Long Lesion substudy (ClinicalTrials.gov identifier NCT02574481) is a prospective, single-arm, multicenter trial of the Eluvia Drug-Eluting Vascular Stent for treating femoropopliteal lesions >140 mm and ≤190 mm in length. Fifty patients (mean age 68.2 years; 32 men) with long lesions (mean length 162.8±34.7 mm) were enrolled; 20 patients had diabetes. Fourteen of the lesions were severely calcified and 16 were occluded. Primary patency (duplex ultrasound peak systolic velocity ratio ≤2.4 in the absence of clinically-driven target lesion revascularization or bypass of the target lesion) and major adverse events [30-day all-cause death and 1-year target limb major amputation or target lesion revascularization (TLR)] were assessed at 12 months. Results: At 12 months, no deaths, target limb amputations, or stent thrombosis had occurred. The Kaplan-Meier estimate of primary patency was 91.0% (95% CI 82.5% to 99.6%). The MAE-free rate at 12 months was 93.5% due to 3 clinically-driven TLRs. The corresponding Kaplan-Meier estimate of freedom from TLR was 93.9% (95% CI 87.2% to 100%). Conclusion: The IMPERIAL Long Lesion substudy demonstrated excellent patency and safety through 1 year among patients with long femoropopliteal occlusive disease treated with the Eluvia stent.

Prospective Evaluation of the TIGRIS Vascular Stent Within a Modern Treatment Algorithm

Purpose: To prospectively evaluate the safety and efficacy of the TIGRIS Vascular Stent in the superficial femoral artery (SFA) and proximal popliteal artery within a treatment algorithm that reserved stent usage for more challenging patients. Materials and Methods: This prospective, single-center study enrolled 97 patients (mean age 68.7 years; 66 men) who were treated for 100 de novo or nonstented restenotic femoropopliteal lesions (≥70% stenosis) and had recoil or dissection after plain balloon predilation. The average lesion length was 5.6±2.3 cm (maximum 8 cm per protocol). The composite primary efficacy outcome was 12-month primary patency, defined as a peak systolic velocity ratio ≤2.5 at the stented target lesion on duplex ultrasound, and no clinically-driven reintervention within the stented segment. The primary safety outcome was freedom from device- and procedure-related target vessel revascularization, target limb major amputation (above the metatarsals), or death through 30 days. Secondary outcomes included secondary patency, clinically-driven target lesion revascularization (TLR), Rutherford category change relative to baseline, and binary restenosis of the target lesion. Results: All devices were successfully implanted with no device-related complications at the time of implant or within the 30-day postimplant window. The average stented length was 7.0±2.5 cm; no stent elongation was observed during deployment. One patient was lost to follow-up before 12 months and another died of an unrelated cause, leaving 95 patients (98 lesions) available for 12-month follow-up and 77 patients/lesions for the 24-month preliminary analysis. The binary primary and secondary patency rates at 12 months were 92.9% and 100%. The binary freedom from TLR was 94.9%. At 24 months, the Kaplan-Meier estimate of primary patency was 90.0%. Conclusion: This prospective study demonstrated that the TIGRIS Vascular Stent is a safe and effective device in a modern treatment algorithm that reserved bare stent use for postangioplasty dissection or recoil in distal femoropopliteal arteries.

Antithrombotic Therapy After Revascularization in Patients With Peripheral Arterial Disease: What Is Here, What Is Next

Objective:

The optimal antithrombotic regimen in peripheral arterial disease (PAD) is not known, leading to significant variations in antithrombotic treatment protocols in randomized trials and clinical practice. In device trials, antithrombotic regimens in patients receiving peripheral vascular interventions have not been clearly reported on. This review summarizes and discusses the most recent evidence on this topic to provide a potential guide to clinical practice.

Methods:

A search of the literature was done for publications that reported outcomes of major PAD device trials. Reported outcomes and various antithrombotic regimens were studied.

Results:

Use of antithrombotic therapy varied significantly between various device trials. Reporting of antithrombotic regimens at the time of follow-up is lacking.

Conclusion:

Outcome data on optimal antithrombotic regimens are presently lacking largely due to the significant heterogeneity and underreporting of antithrombotic regimens at follow-up among prior clinical trials. Standardization and reporting of precise antithrombotic regimens at various points of follow-up in device trials of patients with PAD should be attempted so as to minimize differences in treatment patterns when evaluating new devices.

One-Year Clinical Outcomes following Implantation of InnovaTM Self-Expanding Nitinol Stents in Patients with Peripheral Artery Diseases Presenting Femoropopliteal Artery Lesions

Aim: Although the Innova™ self-expanding nitinol stent (Boston Scientific, Marlborough, MA) exhibits acceptable performance in long-term safety and efficacy when used for the treatment of femoropopliteal (FP) lesions, clinical outcomes following its implantation have not been systematically studied in real-world settings. We investigated the one-year clinical outcomes after implantation of Innova™ self-expanding nitinol stents for the treatment of FP lesions in real-world settings.

Methods: In this multicenter study, 481 lesions in 453 consecutive patients with peripheral artery disease (PAD) (74 ± 9 years; male, 70%; diabetes mellitus, 61%; dialysis, 27%; critical limb ischemia, 37%) who underwent endovascular therapy with the implantation of Innova™ self-expanding nitinol stents for FP lesions were analyzed from February 2016 to April 2017. The primary endpoint was one-year restenosis, whereas the secondary endpoints included one-year major adverse limb events and predictors for one-year restenosis.

Results: The mean lesion length was 18 ± 10 cm. One-year restenosis and major adverse limb event rates were 36% and 18%, respectively. Multivariate analysis revealed that the presence of diabetes mellitus (odds ratio [OR]: 1.83; 95% confidence interval [CI]: 1.07–3.13), distal reference vessel diameter (OR: 1.86; 95% CI: 1.09–3.16), spot stenting (OR: 2.27; 95% CI: 1.27–4.06), and lack of one-year cilostazol treatment (OR: 0.58; 95% CI: 0.33–1.00) were independent risk factors for one-year restenosis.

Conclusion: The current study demonstrated one-year clinical outcomes after Innova™ self-expanding nitinol stent placement for the treatment of FP lesions, including challenging cases in real-world settings.

Eluvia drug-eluting vascular stent system for the treatment of symptomatic femoropopliteal lesions

Endovascular options are increasingly recognized as primary treatments for lower extremity peripheral arterial disease inadequately responsive to noninvasive therapy. Options include balloon angioplasty and stent implantation, and newer technologies incorporate drug coatings to prevent restenosis and reduce the need for reintervention. The Eluvia drug-eluting vascular stent system (Boston Scientific, MA, USA) was designed with a biocompatible fluoropolymer coating to allow for drug elution over time. Initial clinical results demonstrate promising efficacy in terms of sustained femoropopliteal artery patency along with a good safety profile. This review summarizes the existing clinical literature on treatment of femoropopliteal artery lesions with Eluvia, and outlines the continuing research program.

Nitinol Stents in the Femoropopliteal Artery: A Mechanical Perspective on Material, Design, and Performance

Endovascular stenting has matured into a commonly used treatment for peripheral arterial disease (PAD) due to its minimally invasive nature and associated reductions in short-term morbidity and mortality. The mechanical properties of the superelastic Nitinol alloy have played a major role in the explosion of peripheral artery stenting, with modern stents demonstrating reasonable resilience and durability. Yet in the superficial femoral and popliteal arteries, even the newest generation Nitinol stents continue to demonstrate clinical outcomes that leave significant room for improvement. Restenosis and progression of native arterial disease often lead to recurrence of symptoms and reinterventions that increase morbidity and health care expenditures. One of the main factors thought to be associated with stent failure in the femoropopliteal artery (FPA) is the unique and highly dynamic mechanical environment of the lower limb. Clinical and experimental data demonstrate that the FPA undergoes significant deformations with limb flexion. It is hypothesized that the inability of many existing stent designs to conform to these deformations likely plays a role in reconstruction failure, as repetitive movements of the leg and thigh combine with mechanical mismatch between the artery and the stent and result in mechanical damage to both the artery and the stent. In this review we will identify challenges and provide a mechanical perspective of FPA stenting, and then discuss current research directions with promise to provide a better understanding of Nitinol, specific features of stent design, and improved characterization of the biomechanical environment of the FPA to facilitate development of better stents for patients with PAD.

Long-Term Results from the MAJESTIC Trial of the Eluvia Paclitaxel-Eluting Stent for Femoropopliteal Treatment: 3-Year Follow-up

PURPOSE

To report the 3-year results of the MAJESTIC first-in-human study of the Eluvia Drug-Eluting Vascular Stent System for treating femoropopliteal artery lesions.

METHODS

The prospective, single-arm, multicenter clinical trial enrolled 57 patients with symptomatic lower limb ischemia (Rutherford category 2, 3, or 4) and lesions in the superficial femoral artery or proximal popliteal artery. Mean lesion length was 70.8 ± 28.1 mm, and 46% of lesions were occluded. Efficacy measures at 2 years included primary patency, defined as duplex ultrasound peak systolic velocity ratio of ≤2.5 and the absence of target lesion revascularization (TLR) or bypass. Safety monitoring through 3 years included adverse events and TLR.

RESULTS

Primary patency was estimated as 83.5% (Kaplan-Meier analysis) at 24 months, and 90.6% (48/53) of patients maintained an improvement in Rutherford class. At 36 months, the Kaplan-Meier estimate of freedom from TLR was 85.3%. No stent fractures were identified, and no major target limb amputations occurred.

CONCLUSION

MAJESTIC results demonstrated long-term treatment durability among patients whose femoropopliteal arteries were treated with the paclitaxel-eluting Eluvia stent.

LEVEL OF EVIDENCE

Level 2b, cohort study.