Eluvia™ peripheral stent system for the treatment of peripheral lesions above the knee

Polymer-based drug-eluting stent treatment extends the time to reintervention for patients with symptomatic femoropopliteal artery disease: clinical evidence and potential economic value

Aim: Use long-term follow-up data from the IMPERIAL study to determine whether drug-eluting polymer-based nitinol stent treatment can delay the time to repeat intervention for femoropopliteal artery disease and how such a delay may result in cost savings in a value-based episode of care. Patients & methods: The IMPERIAL randomized controlled trial was an international study of a paclitaxel-eluting polymer-coated stent (Eluvia, Boston Scientific, MA, USA) versus a polymer-free paclitaxel-coated stent (Zilver PTX, Cook Corporation, IN, USA) for treating lesions of the femoropopliteal arterial segment. Study patients (n = 465) had symptomatic lower limb ischemia. Safety and efficacy assessments were performed through 5 years. Mean time to first reintervention was calculated in post-hoc analysis for patients who underwent a clinically driven target lesion revascularization (CD-TLR) through 3 or 5 years following the index procedure. To simulate potential cost savings associated with differential CD-TLR burden over time, a cost-avoidance analysis using input parameters from IMPERIAL and US 100% Medicare standard analytical files was developed. Results: Among patients with a first CD-TLR through 3 years of follow-up, mean time to reintervention was 5.5 months longer (difference 166 days, 95% CI: 51, 282 days; p = 0.0058) for patients treated with Eluvia (n = 56) than for those treated with Zilver PTX (n = 30). Through the 5-year study follow-up period, CD-TLR rates were 29.3% (68/232) for Eluvia and 34.2% (39/114) for Zilver PTX (p = 0.3540) and mean time to first reintervention exceeded 2 years for patients treated with Eluvia at 737 days versus 645 days for the Zilver PTX group (difference 92 days, 95% CI: -85, 269 days; p = 0.3099). Simulated savings considering reinterventions occurring over 1 and 5 years following initial use of Eluvia over Zilver PTX were US $1,395,635 and US $1,531,795, respectively, when IMPERIAL CD-TLR rates were extrapolated to 1000 patients. Conclusion: IMPERIAL data suggest initial treatment with Eluvia extends the time patients spend without undergoing reintervention. This extension may be associated with cost savings in relevant time frames.

Comparative Evaluation of Two Paclitaxel-Coated Stents in an Experimental Setting

INTRODUCTION

Unlike paclitaxel-coated balloons, pre-clinical data comparing different paclitaxel-coated stents (PCSs) are weak. The study objective was to compare the features of the 2 main PCSs: Eluvia® (Boston Scientific, Marlborough, MA) versus ZilverPTX® (Cook Medical, Bloomington, IN).

METHOD

Analysis was carried out on 12 pigs divided into 2 groups: Eluvia® (n=6) and ZilverPTX® (n=6). The pigs received the PCS corresponding to their group in each external iliac artery and were paired one by one, to examine 6 different post-implantation timepoints: after 30 minutes, 6 hours, 24 hours, 3 days, 7 days, and 14 days. The paclitaxel concentration measurements and the histological analysis were carried out under blind testing on the plasma, arterial, lymph node, and muscle samples. A linear regression model and Wilcoxon Mann-Whitney test were used to study the variables.

RESULTS

The plasma paclitaxel rate decrease over 24 hours after PCS implantation was significantly different between the two groups, expressed by the correlation coefficient 0.19 (0.14-0.23; p<0.001) with an undetectable concentration at the 10th hour for Eluvia® versus 3 days for ZilverPTX®. Significantly higher paclitaxel concentrations with ZilverPTX® PCS were observed in muscle samples at each timepoint: extensor digitorum brevis 3.2 (1.17-5.23; p=0.005), biceps femoris 4.27 (2.27-6.26; p<0.001), semi-tendinosus 3.79 (1.85-5.73; p=0.001), tibialis anterior 3.0 (1.37-4.64; p=0.001), and in the femoral nodes 2.27±1.74 ng/g versus 0.14±0.13 ng/g (p<0.001). Histological analysis revealed a trend for more marked intimal inflammation in the arteries stented with ZilverPTX® (p=0.063), especially after the 7th and 14th days.

CONCLUSION

Such a difference in the concentration of paclitaxel in the plasma, muscles, and lymph nodes between the two stents was higher than expected based on differences in device design. The clinical consequences of these results remain to be elucidated, particularly regarding the concerning presence of paclitaxel in muscles and adjacent lymph nodes.

CLINICAL IMPACT

This experimental study compares 2 paclitaxel-coated stents. It demonstrates that differences in stent designs and drug features (coatings and concentrations) translate into differences in terms of concentrations of paclitaxel in the plasma, muscles, and lymph nodes. Our results favor the Eluvia® stent over the ZilverPTX® stent, although more studies are required to confirm this conclusion.

Hypoechoic Halo Imaging Findings Following Femoropopliteal Artery Stent Implantation: Risk Factors and Clinical Outcomes

BACKGROUND

Hypoechoic peri-stent areas in duplex ultrasonography (DUS) (ie, "halo") have been noted following femoropopliteal artery stenting.

OBJECTIVES

This study sought to investigate the prevalence, risk factors, and potential safety implications of hypoechoic halos identified with DUS following stent implantation in the IMPERIAL (ELUVIA Drug-Eluting Stent Versus Zilver PTX Stent) and EMINENT (Trial Comparing ELUVIA Versus Bare Metal Stent in Treatment of Superficial Femoral and/or Proximal Popliteal Artery) trials.

METHODS

The IMPERIAL and EMINENT studies of femoropopliteal artery stenting included polymer-based drug-eluting stent, nonpolymer drug-coated stent, and bare metal stent treatment arms. A dedicated DUS protocol was implemented for core laboratory assessment of halo presence at study follow-up visits. Logistic regressions were used to investigate risk factors for a halo sign and its impact on clinically driven target lesion revascularization and primary patency.

RESULTS

Diagnostic DUS imaging from 659 patients was obtained at time points ranging from 6 months to 5 years post-stent implantation. Halo prevalence ranged from 20% to 35% of patients with diagnostic DUS and was present at all time intervals. Halos were identified surrounding all stent types. In analyses of patients with diagnostic imaging from at least 2 visits, halo presence typically persisted, with occasional cases of regression and development at later times. No statistically significant association was found for halo status (ie, halo vs no halo) on 1-year clinically driven target lesion revascularization (OR: 1.27; 95% CI: 0.70-2.30; P = 0.4240) or primary patency (OR: 0.68; 95% CI: 0.43-1.07; P = 0.0927).

CONCLUSIONS

A hypoechoic halo following a femoropopliteal stent procedure is a common occurrence associated with all studied stent types. The presence of a halo appears to be benign with no associated clinical sequelae or effect on target vessel revascularization rates within 1 year of stent implantation.

Outcomes of the paclitaxel-eluting Eluvia stent for long femoropopliteal lesions in Asian patients with predominantly chronic limb-threatening ischemia

The fluoropolymer-coated, paclitaxel-eluting Eluvia stent has shown promising results for the endovascular treatment of femoropopliteal artery lesions in patients with claudication. The aim of the current study was to evaluate efficacy and safety outcomes of the Eluvia stent for the treatment of long femoropopliteal lesions in Asian patients. This is a single-center, retrospective study. The primary endpoint was primary patency at 1 year. Secondary outcomes were 30-days complication rate, technical success, 1-year freedom from clinically driven target lesion revascularization (CD-TLR), limb salvage, survival, amputation-free survival (AFS), wound healing, and clinical improvement. A total of 64 patients with 67 femoropopliteal lesions were included; 78% suffered from diabetes and 84% had chronic limb-threatening ischemia (CLTI). Of those with ischemic wounds, 79% did not have run-off to the foot. Mean lesion length was 193 ± 128 mm and 52% were severely calcified. Primary patency at 1 year was 84% in the overall cohort and 91% in patients with complete lesion coverage with the Eluvia stent. Technical success was achieved in 100% of the cases and 30-day complications occurred in six patients. Twelve-month freedom from CD-TLR, limb salvage, survival, and AFS were 92%, 93%, 85%, and 80%, respectively. In 80% of patients, complete wound healing was experienced and 84% had clinical improvement after 1 year. The Eluvia stent showed promising 12-month patency and clinical results for femoropopliteal treatment in this CLTI-dominant patient population with severely calcified, long lesions. Patient numbers were, however, small; larger trials are required to validate these findings. Aneurysmal change seen in some cases also needs further investigation.

Current developments in endovascular therapy of peripheral vascular disease

More than 200 million people worldwide have peripheral artery disease (PAD) or its most severe manifestation, critical limb ischemia (CLI). While endovascular treatment has become first line therapy in most cases, a number of challenges remain for optimal treatment of femoropopliteal (FP) or infrapopliteal (IP) disease, especially when these lesions are severely calcified, chronic total occlusions (CTOs) or in-stent restenosis (ISR). Continued evolution of technologies has significantly improved the outcomes for endovascular treatment. A number of new devices are in the pipeline right now, including new paclitaxel eluting stents and balloons, intravascular lithotripsy to treat severely calcified lesions, adventitial delivery of anti-restenotic agents to limit restenosis rates, and percutaneous femoro-popliteal bypass.

Newly approved devices for endovascular treatment of femoropopliteal disease: a review of clinical evidence

Introduction: Femoropopliteal lesions account for a significant proportion of endovascular interventions for peripheral artery disease. In this manuscript, we review the literature on the application of newly approved devices in the treatment of atherosclerotic lesions at this segment.Areas covered: New drug-coating technologies provide sustained drug-eluting over time and better scaffolds are more resistant to the increased biomechanical stress at the femoropopliteal segment. Thus, the newer drug-eluting stents (i.e. Eluvia®), nitinol interwoven stents (i.e. Supera®), and drug-coated balloons (i.e. Stellarex®) are associated with improved pharmacokinetic profiles and promising primary patency rates. A major predictor of technical failure and restenosis is the calcification of the target vessel. Recently, intravascular lithotripsy of calcified lesions at the femoropopliteal segment with the Shockwave® balloon was introduced as a feasible treatment option for these complex lesions. Finally, we also describe the Tack Endovascular System®, the first-of-its-type, for the repair of post-angioplasty dissections.Expert opinion: The use of innovative stent designs and novel drug-coating, the application of adjunctive intravascular lithotripsy, and the combined use of new devices treating complications might improve the overall outcomes of angioplasty, thereby promising favorable outcomes even for more complex lesions.

Opening Act: New Multidisciplinary Approaches Yield Thinner, Stronger, Better Stents

When an artery is blocked, stents are often the best way to open up the vessel. A mesh stent is tightly crimped over a tiny balloon and guided to the troubled spot; the balloon is inflated, expanding the stent, which forces the vessel open. Blood flow is restored.

Electrospun Produced 3D Matrices for Covering of Vascular Stents: Paclitaxel Release Depending on Fiber Structure and Composition of the External Environment

Paclitaxel is a natural, highly lipophilic anti proliferative drug widely used in medicine. We have studied the release of tritium-labeled paclitaxel (³H-PTX) from matrices destined for the coating of vascular stents and produced by the electrospinning method from the solutions of polycaprolactone (PCL) with paclitaxel (PTX) in hexafluoisopropanol (HFIP) and/or solutions of PCL with PTX and human serum albumin (HSA) in HFIP or HIFP-dimethyl sulphoxide (DMSO) blend. The release of PTX has been shown to depend on the composition of electrospinning solution, as well as the surrounding medium, particularly the concentration of free PTX and PTX-binding biomolecules present in human serum. It was shown that 3D matrices can completely release PTX without weight loss. Two-phase PTX release from optimized 3D matrices was obtained: ~27% of PTX was released in the first day, another 8% were released over the next 26 days. Wherein ~2.8%, ~2.3%, and ~0.25% of PTX was released on day 3, 9, and 27, respectively. Considering PTX toxicity, the rate of its diffusion through the arterial wall, and the data obtained the minimum cytostatic dose of the drug in the arterial wall will be maintained for at least three months.

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.

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

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

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.