In the long saga of ABSORB trials, the ABSORB IV trial presented at the TCT conference 2018 showed that polymeric coronary bioresorbable vascular scaffolds (BVS) were non-inferior to cobalt-chromium-based Xience DES for cardiovascular outcomes of target lesion failure and angina in fairly simple lesion types, with lower acute procedural success in a 1 year period. The results for this trial were published today in The Lancet.
Past literature had shown a higher number of adverse events with coronary bioresorbable vascular scaffolds (BVS) as compared with metallic drug-eluting stents (DES). However, these trials did not paint the right picture as patients with smaller lesions than intended for the scaffold were frequently enrolled, implantation technique used was suboptimal, and patients with myocardial infarction, in whom BVS could be well suited, were excluded. In the light of this, Stone and his colleagues aimed to assess the safety and efficacy of Absorb bioresorbable vascular scaffolds (BVS) compared with Xience drug-eluting stent (DES) using appropriate implantation techniques in the largest bioresorbable scaffold trial conducted to date.
In this active-controlled, blinded, multicenter, randomized trial, the investigators enrolled patients with stable coronary artery disease or acute coronary syndromes aged 18 years or older from 147 hospitals in five countries (the USA, Germany, Australia, Singapore, and Canada). A total of 2604 enrollees were randomly assigned (1:1) to receive polymeric everolimus-eluting BVS (Absorb) with optimized implantation technique or cobalt-chromium everolimus-eluting stents (EES; Xience). Patients were stratified by diabetic status and similarity to ABSORB III. The primary endpoint was target lesion failure (cardiac death, target vessel myocardial infarction, or ischemia-driven target lesion revascularization) at 30 days, tested for non-inferiority with a 2·9% margin for the risk difference. The analysis was by intention to treat.
[perfectpullquote align=”full” bordertop=”false” cite=”” link=”” color=”” class=”” size=””]“It was a very, very interesting study. Better technique, better patient selection, and appropriate types of lesions do bring down this difference and I honestly believe that now all we need is a better device that will hopefully eliminate most or all of these early first 3 year differences, potentially allowing the long-term benefits of ABSORB to emerge.”- Dr. Gregg Stone, M.D.[/perfectpullquote]
The investigators found that the primary endpoint of target lesion failure at 30 days occurred in 5·0% and 3·7% in patients assigned to BVS and Xience respectively (Difference 1·3%, upper 97·5% confidence limit 2·89; one-sided p non-inferiority=0·0244). Target lesion failure at 1 year occurred in 7·8% of patients assigned to BVS and 6·4% patients assigned to EES (difference 1·4%, upper 97·5% confidence limit 3·4; one-sided p non-inferiority=0·0006). Angina at 1 year occurred in 20·3% patients assigned to BVS and 20·5% patients assigned to EES (difference −0·3%, 95% CI −3·4% to 2·9%; one-sided p non-inferiority=0·0008; two-sided p superiority=0·8603). Device thrombosis within 1 year occurred in 0·7% of patients assigned to BVS and 0·3% patients assigned to EES (p=0·1586).
In the study, Stone concluded that Absorb BVS was non-inferior to cobalt-chromium-based Xience DES up to 1 year for cardiovascular outcomes in fairly simple lesion types. Although the results were better for BVS compared with ABSORB III, there was also an improvement in the results in the Xience DES arm. In ABSORB IV, BVS event rates were still numerically higher compared with Xience DES. While ABSORB IV adds to the data on first-generation BVS, longer-term data, as well as trials with improved stent design and implementation techniques, are awaited. Speaking of the improvement in the results from ABSORB III, Dr. Stone said, “It was a very, very interesting study. Better technique, better patient selection, and appropriate types of lesions do bring down this difference and I honestly believe that now all we need is a better device that will hopefully eliminate most or all of these early first 3 year differences, potentially allowing the long-term benefits of ABSORB to emerge.”
To view the interview with Dr. C. Michael Gibson, click here.