Re-endothelialisation after Synergy stent and Absorb bioresorbable vascular scaffold implantation in acute myocardial infarction: COVER-AMI study

Abstract

Background/aims: Drug eluting stent (DES) decrease the risk of restenosis by reducing the neointimal response. However, DES may impair strut coverage, and this has been associated with late stent/scaffold thrombosis. Bioresorbable vascular scaffold (BVS) may overcome the risk of stent/scaffold thrombosis when completely resorbed. The purpose of this randomised trial was to compare the arterial healing response in the short term, as a surrogate for safety and efficacy, between the metallic everolimus-eluting stent (Synergy; Boston Scientific, Marlborough, MA, USA) and the everolimus BVS (Absorb; Abbott Vascular, Santa Clara, CA, USA) in the particular setting of acute myocardial infarction (AMI). This pilot study sought to compare the neointimal response of metallic everolimus DES (Synergy) with polymeric everolimus BVS (Absorb) by optical coherence tomography (OCT) 3 months after an AMI. Methods: COVER-AMI was a single-centre, single-blind, non-inferiority, randomised controlled trial. Patients with ST segment elevation myocardial infarction (STEMI) who underwent primary percutaneous coronary intervention were randomly allocated (1:1) to treatment with the Synergy DES or Absorb BVS. The primary endpoint was the 3-month neointimal response assessed as the percentage of uncovered struts, neointimal thickness, in-stent/scaffold area obstruction, and pattern of neointima. The main secondary endpoint included the device-oriented composite endpoint according to the Academic Research Consortium definition. Results: Twenty patients without clinical and/or angiographic complications (Synergy (n = 10) or BVS (n = 10); mean age 59.0 years; 20% female) were enrolled in our centre. The stent diameter was higher in the Synergy group (3.7 ± 0.4 mm vs 3.4 ± 0.4 mm in the BVS group, p = 0.01). At 3 months, no significant differences in angiographic lumen loss were observed between the everolimus DES and everolimus BVS (0.04 mm (IQR 0.00-0.07) vs 0.11 mm (IQR 0.04-0.31), p = 0.165). OCT analysis of 420 cross-sections showed that the total neointimal area and in-stent obstruction were lower in the Synergy group, while OCT analysis at the strut level (n = 3942 struts) showed that the rate of uncovered struts was lower in the BVS group. Conclusions: Stenting of culprit lesions in the setting of STEMI resulted in a nearly complete arterial healing for both the Synergy and the BVS devices. Lower neointimal thickness and in-stent obstruction but a higher rate of uncovered struts were observed in the Synergy group. These findings provide the basis for further exploration in clinically oriented outcome trials.