Biovascular scaffold linked to more adverse events, thrombosis vs metallic everolimus-eluting stent
Patients undergoing percutaneous coronary intervention who received bioresorbable vascular scaffolds (BVS) had a higher rate of device-oriented adverse events and device thrombosis up to 2 years later compared with those who had received metallic everolimus-eluting stents (EES), according to a systematic review and meta-analyses.
At 2-year follow-up, more patients given BVS had target vessel-related myocardial infarction (MI) compared with those given EES (5.8 percent vs 3.2 percent; relative risk [RR], 1.68, 95 percent confidence interval [CI], 1.29–2.19; p=0.0003). Patients with BVS also had a higher rate of ischaemia-driven target lesion revascularization compared with patients with EES (5.3 percent vs 3.9 percent; RR, 1.40, 95 percent CI, 1.09–1.80; p=0.0090). [Lancet 2017;doi:10.1016/S0140-6736(17)31470-8]
These led to a higher 2-year relative risk of the device-oriented composite endpoint of target lesion failure in BVS vs EES recipients (9.4 percent vs 7.4 percent; RR, 1.29, 95 percent CI, 1.08–1.56; p=0.0059), though the difference in cardiac mortality between the two treatment arms was nonsignificant.
Incidence of device thrombosis at 2 years was also higher among BVS vs EES recipients (2.3 percent vs 0.7 percent; RR, 3.35, 95 percent CI, 1.96–5.72; p<0.0001).
However, upon exclusion of device thrombosis-related events, the difference between BVS and EES in terms of the device-oriented composite endpoint was no longer significant.
“[This suggests] that scaffold thrombosis is the key factor to be targeted in future device iterations,” said Drs Raffaele Piccolo and Stephan Windecker from Bern University Hospital in Switzerland and Dr Peter Jüni from the University of Toronto in Canada, in a commentary. [Lancet 2017;doi:10.1016/S0140-6736(17)31871-8]
Rates of the device-oriented composite endpoint and device thrombosis were also higher between 1 and 2 years post-implantation in patients with BVS vs EES (3.3 percent vs 1.9 percent; RR, 1.64; p=0.0376 and 0.5 percent vs none; p<0.0001, respectively).
“In addition to device underexpansion, the natural process of scaffold resorption might [also] contribute to adverse events occurring beyond 1 year,” said the researchers. “[A]voiding very small vessels and maximizing scaffold expansion could improve long-term BVS outcomes.”
However, the researchers advised caution in interpreting the study findings.
“These results need to be placed in perspective since BVS is a first-generation device that was used for the first time by most operators in the included studies, before the importance of a BVS-specific technique to optimize outcomes became appreciated.”
“The best available evidence suggests that early and late BVS events can be minimized by avoiding BVS use in very small vessels [reference vessel diameter <2.5 mm], by routine high-pressure noncompliant balloon postdilatation, and by having a low threshold for use of intravascular imaging guidance and prolonged dual antiplatelet therapy for up to 3 years in patients who are not at high risk of bleeding,” they said, and called for long-term follow-up to assess the risks and benefits of BVS vs EES beyond 2 years.
“[S]everal unmet clinical needs remain unsolved favouring BVS technology … the data of the current study must be used to inform ongoing and future research,” said Piccolo, Jüni, and Windecker.
The systematic review and meta-analyses included 5,583 participants of seven randomized trials who had received either an everolimus-eluting BVS (n=3,261) or metallic EES (n=2,322; mostly cobalt-chromium EES [n=2,242]) and been followed up for a minimum of 2 years.