Bare metal stent versus paclitaxel eluting stent for intermediate length femoropopliteal arterial lesions (BATTLE trial): study protocol for a randomized controlled trial

A real-world experience of drug eluting and non-drug eluting stents in lower extremity peripheral arterial disease

Objectives

Drug-eluting stents (DES) have been promoted as an alternative to the traditional non-drug eluting stents (nDES), and offer the potential for improved patency rates. However, DES are more expensive than nDES, and results comparing these stents outside of clinical trials have been limited.

Materials and methods

A retrospective review was performed on all in patient infrainguinal lower extremity endovascular procedures between January 2014 and September 2016, which involved stent implantation. Procedures involving the common femoral artery, superficial femoral artery, and above knee popliteal artery were included. Procedures involving iliac, below knee popliteal, tibial, peroneal, and pedal arteries were excluded. The type of stent, number of stents, length of each stent, and location of stent were recorded for each procedure. Data on each patients Trans-Atlantic Inter Society Consensus II class were collected. End-points included stent thrombosis, restenosis, re-intervention, and limb loss. Post-operative arterial duplexes were obtained every three months to determine stent patency during follow-up visits. In-stent stenosis was defined as >60% narrowing on arterial duplex. Thrombosis was defined as in-stent occlusion, and limb loss involved only major amputations in the treated extremity. Bivariate analysis and Students two-sample T-test were used to analyze the data. IBM-SPSS – 22 was used for all analyses.

Results

Two hundred and twelve patients underwent at total of 252 procedures during the study period. Of this group, 191 procedures met inclusion criteria. There were 21 lesions that were treated with both nDES and DES and they were excluded from further analysis. The average patient age was 73.2 ± 11.6 years; 68.6% had hypertension, and 58.1% had diabetes. Mean follow-up was 7.18 ± 7.96 months. The most common indication for intervention was claudication (53%), followed by critical limb threatening ischemia (47%); 124 procedures involved only nDES (Lifestent®)(Bard, Tempe, AZ), 46 procedures involved only DES (Zilver®) (Cook, Bloomington, IN). Comparison of nDES and DES showed the overall rate of thrombosis (11.1% vs. 16.7%, p = 0.81), overall rates of re-stenosis (48.2% vs. 46%, p = 1.0), re-intervention (13.7% vs. 14.3%, p = 1.0), and limb loss (9.7% vs. 0.0%, p = 0.38) was equivalent between the groups. The six-month primary patency rate for nDES and DES (41.9% vs. 40.0%, p = 1.0) was also equivalent. On average, the average lengths of nDES were longer than DES (19.2 ± 14.3 cm vs.11.4 ± 5.7 cm) ( p < .0001). DES results showed overall rates of 33% re-stenosis, 7.1% thrombosis, and no limb loss. There were no statistical differences between the nDES or DES groups with respect to gender, age, laterality, diabetes mellitus, coronary artery disease, gangrene, ulcers, hyperlipidemia, atrial fibrillation, deep vein thrombosis, claudication, critical limb-threatening ischemia, ipsilateral bypass, re-stenosis, thrombosis, limb loss, or ipsilateral amputation. Bivariate analysis showed a higher incidence of hypertension for nDES patients ( p = .001). There was no statistical difference between Trans-Atlantic Inter Society Consensus II classes and type of stent used ( p = .95).

Conclusions

In this retrospective analysis from one institution, the use of an nDES or DES did not result in a statistically significant difference in the rate of thrombosis, re-stenosis, ipsilateral re-intervention, or ipsilateral amputation over a two-year period when involving the CFA, SFA, and above knee popliteal artery.

Risk of Death Following Application of Paclitaxel-Coated Balloons and Stents in the Femoropopliteal Artery of the Leg: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background Several randomized controlled trials ( RCT s) have already shown that paclitaxel-coated balloons and stents significantly reduce the rates of vessel restenosis and target lesion revascularization after lower extremity interventions. Methods and Results A systematic review and meta-analysis of RCT s investigating paclitaxel-coated devices in the femoral and/or popliteal arteries was performed. The primary safety measure was all-cause patient death. Risk ratios and risk differences were pooled with a random effects model. In all, 28 RCT s with 4663 patients (89% intermittent claudication) were analyzed. All-cause patient death at 1 year (28 RCT s with 4432 cases) was similar between paclitaxel-coated devices and control arms (2.3% versus 2.3% crude risk of death; risk ratio, 1.08; 95% CI, 0.72-1.61). All-cause death at 2 years (12 RCT s with 2316 cases) was significantly increased in the case of paclitaxel versus control (7.2% versus 3.8% crude risk of death; risk ratio, 1.68; 95% CI, 1.15-2.47; -number-needed-to-harm, 29 patients [95% CI , 19-59]). All-cause death up to 5 years (3 RCT s with 863 cases) increased further in the case of paclitaxel (14.7% versus 8.1% crude risk of death; risk ratio, 1.93; 95% CI , 1.27-2.93; -number-needed-to-harm, 14 patients [95% CI , 9-32]). Meta-regression showed a significant relationship between exposure to paclitaxel (dose-time product) and absolute risk of death (0.4±0.1% excess risk of death per paclitaxel mg-year; P<0.001). Trial sequential analysis excluded false-positive findings with 99% certainty (2-sided α, 1.0%). Conclusions There is increased risk of death following application of paclitaxel-coated balloons and stents in the femoropopliteal artery of the lower limbs. Further investigations are urgently warranted. Clinical Trial Registration URL : www.crd.york.ac.uk/PROSPERO . Unique identifier: CRD 42018099447.

Drug-Eluting Stents for Treatment of Peripheral Artery Disease

Endovascular intervention is a mainstay treatment of peripheral artery disease (PAD) in addition to aggressive risk factor modification and exercise programs in patients with favorable anatomy or in those who are considered too high risk for surgical intervention. Treatment with percutaneous transluminal angioplasty (PTA) and bare metal stents (BMS) has been limited by high rates of in-stent restenosis (ISR) requiring repeat revascularization. Drug-eluting stents (DES), developed and designed to reduce ISR, offer a promising solution to the current challenges in endovascular management of PAD. Several randomized clinical trials have shown improved short- and mid-term outcomes with DES as compared with both PTA and BMS. Herein we provide an up-to-date review of the current literature on DES use in PAD.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Self-expanding nitinol stents of high versus low chronic outward force in de novo femoropopliteal occlusive arterial lesions (BIOFLEX-COF trial): study protocol for a randomized controlled trial

Background

Self-expanding nitinol stents must be oversized at least by a minimal amount to ensure contact with the vessel wall and prevent migration. Once the stent is deployed it exerts a continuous force upon the vascular wall, termed chronic outward force (COF). Animal studies have found an increased neointimal hyperplasia in stents with high oversizing and thus high COF. Data about correlation between COF and neointimal hyperplasia in humans are currently lacking. The objective of the BIOFLEX-COF trial is to prospectively investigate differences in formation of intimal hyperplasia at 1 and 2 years after implantation of nitinol stents with high versus low COF in de novo femoropopliteal occlusive arterial lesions.

Methods

The BIOFLEX-COF trial is a prospective, quantitative, randomized study. Eighty subjects with symptomatic peripheral arterial lesions eligible for endovascular stent implantation will be enrolled and randomly assigned to either a high COF group (LifeStent Flexstar, Bard Peripheral Vascular Inc., Tempe, AZ, USA) or low COF group (Pulsar, Biotronik AG, Bülach, Switzerland) using an online randomization program to generate a random 1:1 group allocation (block randomization). After implantation and dilatation, COF at every 2 mm along the stent axis will be calculated from the actual stent diameter versus its nominal diameter.

There will be two follow-up evaluations at 12 and 24 months. Primary endpoint is the amount of in-stent neointima at 1 year, assessed by contrast-enhanced CT angiography (CTA). In the control examinations, stent diameter and true lumen diameter will be measured on DICOM images every 2 mm along the stent axis to quantify the relative amount of in-stent restenosis.

Secondary objectives are the amount of in-stent neointima at 2 years, device- and procedure-related adverse events and target lesion revascularization (TLR) rate.

The scheduled time for recruitment is 2 years. Recruitment is expected to be complete in October 2017.

Discussion

This trial is the first to prospectively investigate the influence of COF on stent patency. If successful, the results will aid in a more precise selection of stent type and size in a given target vessel.

The present study is challenging in that it compares two different self-expanding nitinol stents head-to-head against each other. To optimize the power of this study, traditional binary outcome parameters such as TLR and restenosis at Doppler ultrasound were dropped as primary endpoints. Instead, the amount of neointima inside the stent accessed by CTA was selected as (continuous) outcome parameter.

Trial registration

ClinicalTrials.gov Identifier: NCT03097679. Date of registration: 14 March 2017 (retrospectively registered).

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2338-0) contains supplementary material, which is available to authorized users.

[Proposed model of vascular trauma by mean of mechanical characterization of endovascular prostheses (stents) based on structural analysis by FEA]

OBJECTIVE

The accumulated evidence on angioplasty techniques with stents has raised a controversy about the factors that influence the final vascular response. Indeed, several studies have shown there might be re-stenosis between 30% to 40% about 6 months after placement, relating to the design of the device as one of the main causes. This paper proposes the functional characterization of endovascular stents, analyzing its mechanical influence in the vascular system and predicting implicit traumatic factors in the vessel.

METHODS

A structural analysis was made for several computational models of endovascular stents using Finite Element Analysis in order to predict the mechanical behavior and the vascular trauma. In this way, the stents were considered as tubular devices composed of multiple links under radial pressure loads, reflecting stress concentration effects.

RESULTS

The analysis allowed to visualize how the geometry of stents is adjusted under several load conditions, in order to obtain the response of "solid-solid" interaction between the stent and the arterial wall. Thus, an analysis was performed in order to calculate stress, and a conceptual model that explains its mechanical impact on the stent-vessel interaction, was raised, to infer on the functionality from the design of the devices.

CONCLUSIONS

The proposed conceptual model allows to determine the relationship between the conditions of mechanical interaction of the stents, and warns about the effects in what would be the operation of the device on the vascular environment.