Midterm Safety and Efficacy of ABSORB Bioresorbable Vascular Scaffold Versus Everolimus-Eluting Metallic Stent: An Updated Meta-Analysis

Undiscovered pathology of transient scaffolding t1remains a driver of failures in clinical trials

AIM

To statistically examine the released clinical trials and meta-analyses of polymeric bioresorbable scaffolds resuming the main accomplishments in the field with a translation to the routine clinical practice.

METHODS

The statistical power in clinical trials such as ABSORB Japan, ABSORB China, EVERBIO II, AIDA, and few meta-analyses by the post hoc odds ratio-based sample size calculation, and the patterns of artery remodeling published in papers from ABSORB A and B trials were evaluated.

RESULTS

The phenomenal admiration from the first ABSORB studies in 2006-2013 was replaced by the tremendous disappointment in 2014-2017 due to reported relatively higher rates of target lesion failure (a mean prevalence of 9.16%) and device thrombosis (2.38%) in randomized controlled trials. Otherwise, bioresorbable vascular scaffold (BVS) performs as well as the metallic drug-eluting stent (DES) with a trend toward some benefits for cardiac mortality [risk ratio (RR), 0.58-0.94, P > 0.05]. The underpowered design was confirmed for some studies such as ABSORB Japan, ABSORB China, EVERBIO II, AIDA trials, and meta-analyses of Polimeni, Collet, and Mahmoud with some unintentional bias (judged by the asymmetrical Funnel plot). Scaffold thrombosis rates with Absorb BRS were comparable with DES performed with a so-called strategy of the BVS implantation with optimized pre-dilation (P), sizing (S) and post-dilation (P) (PSP) implantation (RR, PSP vs no PSP 0.37) achieving 0.35 per 100 patient-years, which is comparable to the RR 0.49 with bare-metal stents and the RR 1.06 with everolimus DES. Both ABSORB II and ABSORB III trials were powered enough for a five-year follow-up, but the results were not entirely conclusive due to the mostly non-significant fashion of data. The powered meta-analyses were built mostly on statistically poor findings.

CONCLUSION

The misunderstanding of the pathology of transient scaffolding drives the failures of the clinical trials. More bench studies of the vascular response are required. Several next-generation BVS including multifunctional electronic scaffold grant cardiology with a huge promise to make BVS technology great again.

Mid-term outcomes of the Absorb BVS versus second-generation DES: A systematic review and meta-analysis

Background

Bioresorbable Vascular Scaffolds (BVS) were introduced to overcome some of the limitations of drug-eluting stent (DES) for PCI. Data regarding the clinical outcomes of the BVS versus DES beyond 2 years are emerging.

Objective

To study mid-term outcomes.

Methods

We searched online databases (PubMed/Medline, Embase, CENTRAL), several websites, meeting presentations and scientific session abstracts until August 8^th, 2017 for studies comparing Absorb BVS with second-generation DES. The primary outcome was target lesion failure (TLF). Secondary outcomes were all-cause mortality, myocardial infarction, target lesion revascularization (TLR) and definite/probable device thrombosis. Odds ratios (ORs) with 95% confidence intervals (CIs) were derived using a random effects model.

Results

Ten studies, seven randomized controlled trials and three propensity-matched observational studies, with a total of 7320 patients (BVS n = 4007; DES n = 3313) and a median follow-up duration of 30.5 months, were included. Risk of TLF was increased for BVS-treated patients (OR 1.34 [95% CI: 1.12–1.60], p = 0.001, I² = 0%). This was also the case for all myocardial infarction (1.58 [95% CI: 1.27–1.96], p<0.001, I² = 0%), TLR (1.48 [95% CI: 1.19–1.85], p<0.001, I² = 0%) and definite/probable device thrombosis (of 2.82 (95% CI: 1.86–3.89], p<0.001 and I² = 40.3%). This did not result in a difference in all-cause mortality (0.78 [95% CI: 0.58–1.04], p = 0.09, I² = 0%). OR for very late (>1 year) device thrombosis was 6.10 [95% CI: 1.40–26.65], p = 0.02).

Conclusion

At mid-term follow-up, BVS was associated with an increased risk of TLF, MI, TLR and definite/probable device thrombosis, but this did not result in an increased risk of all-cause mortality.

Long-term outcome of bioresorbable vascular scaffolds for the treatment of coronary artery disease: a meta-analysis of RCTs

BACKGROUND

Coronary bioresorbable scaffolds (BRS) were developed to overcome the limitations of standard metallic stents, especially to address late events after percutaneous coronary interventions. The aim of this meta-analysis was to evaluate the efficacy and safety of BRS, compared with Everolimus-eluting stents (EES), using the data available from randomized trials, with a focus on long-term outcomes.

METHODS

Published randomized trials comparing BRS to EES for the treatment of coronary artery disease were searched for within PubMed, Cochrane Library and Scopus electronic databases up to April 4th 2017. The summary measure used was odds ratio (OR) with 95% confidence intervals.

RESULTS

A total of 5 studies were eligible, including 5219 patients. At 2 years, BRS was associated with higher rates of target lesion failure (9.4% vs 7.2%; OR = 1.33; 95% CI 1.07 to 1.63; p = 0.008) and device thrombosis (2.3% vs 0.7%; OR = 3.22; 95% CI 1.86 to 5.57; p < 0.0001) compared with EES. The incidence of both early (within 30 days after implantation, 1.1% vs 0.5%, OR 1.97, 95% CI 1.02 to 3.81; p = 0.05) and very-late device thrombosis (>1 year, 0.6% vs 0.1%, OR 4.03, 95% CI 1.37 to 11.82; p = 0.01) was higher with BRS compared with EES.

CONCLUSIONS

BRS may be associated with worse two-years clinical outcomes compared with EES in patients with coronary artery disease.

Temporal Trends in Adverse Events After Everolimus-Eluting Bioresorbable Vascular Scaffold Versus Everolimus-Eluting Metallic Stent Implantation

Background:

Bioresorbable coronary stents have been introduced into clinical practice to improve the outcomes of patients treated with percutaneous coronary intervention. The everolimus-eluting bioresorbable vascular scaffold (BVS) is the most studied of these stent platforms; however, recent trials comparing BVS with everolimus-eluting metallic stents (EES) raised concerns about BVS safety. We aimed to assess the efficacy and safety of BVS versus EES in patients undergoing percutaneous coronary intervention.

Methods:

We searched Medline, Embase, the Cochrane Central Register of Controlled Trials, scientific sessions abstracts, and relevant Web sites for randomized trials with a follow-up of ≥2 years investigating percutaneous coronary interventions with BVS versus EES. The primary outcomes of our analysis were definite/probable stent thrombosis (ST) and target lesion failure (TLF; device-oriented composite end point of cardiac death, target vessel myocardial infarction, or ischemia-driven target lesion revascularization [TLR]). Secondary outcomes were target vessel myocardial infarction, TLR, and cardiac death. We calculated the risk estimates for main outcomes according to a fixed-effect model.

Results:

We included 7 trials comprising data for 5583 patients randomized to receive either a BVS (n=3261) or an EES (n=2322). Median follow-up was 24 months (range, 24–36 months). Patients treated with BVS had a higher risk of definite/probable ST compared with patients treated with EES (odds ratio, 3.33; 95% confidence interval, 1.97–5.62; P <0.00001). In particular, patients with BVS had a higher risk of subacute, late, and very late ST, whereas the risk of acute ST was similar. Patients treated with BVS compared with EES had a higher risk at 2 years of TLF (odds ratio, 1.47; 95% confidence interval, 1.14–1.90; P =0.003), driven mainly by an increased risk of target vessel myocardial infarction (odds ratio, 1.73; 95% confidence interval, 1.31–2.28; P =0.0001; I 2 =0%) and of TLR (odds ratio, 1.27; 95% confidence interval, 1.00–1.62; P =0.05). Of importance, the risk of TLF and TLR for patients with BVS was higher between 1 and 2 years, whereas there was no difference in the first year. Risk of cardiac death was similar between the 2 groups.

Conclusions:

Our meta-analysis of randomized trials with a follow-up of ≥2 years demonstrated a higher risk of ST and of TLF in patients treated with BVS compared with EES. Of note, BVS had a higher risk of subacute, late, and very late ST, whereas the risk of TLF and TLR was higher between 1 and 2 years.