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ABSORB III: Adverse events after BVS decline between 3 and 5 years vs. EES
SAN FRANCISCO — Although the rates of adverse events at 5 years were increased among patients assigned a bioresorbable vascular scaffold compared with those assigned an everolimus-eluting metallic coronary stent, beyond 3 years of follow-up, both absolute and relative rates of device-oriented events — target lesion failure and device thrombosis — were markedly reduced among those patients who received the BVS vs. EES, according to new data from the ABSORB III trial presented at the Transcatheter Cardiovascular Therapeutics Scientific Symposium.
The excess risk associated with BVS ended at 3 years, which coincide with the time of complete scaffold resorption, according to the trial investigators in their paper published concurrently in Circulation.
“For us that have been working in this field, and I’ve been a principal investigator for FDA approval trials for at least a dozen different stent designs, this was a revelation,” Dean J. Kereiakes, MD, FACC, FSCAI, medical director of The Christ Hospital Heart and Vascular Center in Cincinnati and professor of clinical medicine at The Ohio State University in Columbus, told Cardiology Today’s Intervention. “It was proof of concept for the first time that following BVS resorption, clinical event rates trend dramatically in the other direction. It should, I believe, renew interest in the development of bioresorbables if they can be engineered or deployed to avoid earlier hazard.”
Three-year data from the ABSORB III trial were presented at TCT 2017. As Cardiology Today’s Intervention previously reported, device-related clinical events occurred between 1 and 3 years among patients assigned a BVS (Absorb, Abbott Vascular) or an EES (Xience, Abbott Vascular), with more events occurring in the BVS group.
The TCT abstract was presented by Stephen G. Ellis, MD, director of interventional cardiology and senior academic officer of the Heart and Vascular Institute at Cleveland Clinic. Researchers analyzed data from patients who underwent PCI for one or two de novo native coronary artery lesions located in separate epicardial coronary vessels. Patients were randomly assigned (2:1) BVS (n = 1,322) or EES (n = 686).
Follow-up was conducted regularly through 5 years to assess the primary study endpoint — target lesion failure at 1 year — and secondary endpoints, which included device thrombosis, TLF and its components at each follow-up period. Individual components of TLF were ischemia-driven target lesion revascularization, cardiac death and target vessel MI.
Five-year follow-up data were available for 86.5% of patients in the BVS group and 87.2% of those in the EES group. Follow-up was conducted for a median of 59.84 months for patients assigned BVS and 59.54 for those assigned EES. Patients who did not complete 5-year follow-up had data available for a median of 36 months.
Patients assigned BVS had increased rates of target vessel MI (10.4% vs. 7.5%; HR = 1.41; 95% CI, 1.02-1.96), TLF (17.5% vs. 15.2%; HR = 1.19; 95% CI, 0.94-1.51) and scaffold thrombosis (2.5% vs. 1.1%; HR = 2.38; 95% CI, 1.05-5.39) at 5 years compared with those assigned EES.
However, the risk for TLF decreased in the BVS group compared with the EES group from 0 to 3 years (HR = 1.35; 95% CI, 1.02-1.78) to 3 to 5 years (HR = 0.82; 95% CI, 0.55-1.24; P for interaction = .052). This decrease was also seen for device thrombosis from 0 to 3 years (HR = 3.23; 95% CI, 1.25-8.3) to 3 to 5 years (HR = 0.26; 95% CI, 0.02-2.86; P for interaction = .056).
“We only have 2 years of observation after device resorption, and there’s no planned follow-up beyond 5 years, which is very unfortunate because longer follow-up (beyond 5 years) would determine if the point estimates favoring BVS remain stable,” Kereiakes said in an interview. “One could predict, based on the relative event rates beyond 3 years, the time of equipoise or even relative net benefit with BVS. The time-to-event curves are going the opposite direction after 3 years, and if this continues, we could predict when BVS might actually become 'better' than Xience.”
Kereiakes added that results from this trial may help in the development of future BVS. “If we could have gotten this device to resorb completely sooner and with less hazard — for example, thinner struts, different polymer processing and better deployment technique — we could have reached this equipoise much sooner and the hazard ratios may have flipped earlier at 18 months. There will be renewed interest in what we call 'dissolvables,' but we know now what we need to improve.” – by Darlene Dobkowski
References:
Ellis SG. Bioresorbable Scaffolds – 1. Presented at: TCT Scientific Symposium; Sept. 25-29, 2019; San Francisco.
Kereiakes DJ, et al. Circulation. 2019;doi:10.1161/CIRCULATIONAHA.119.042584.
Disclosures: The trial was funded by Abbott Vascular. Kereiakes reports he consults for Abbott Vascular, Boston Scientific, Micell Technologies, Sino Medical Sciences Technology and Svelte Medical Systems, and receives research funding from Abbott Vascular and Boston Scientific. Ellis reports he consults for and receives research grants from Abbott Vascular and Boston Scientific. Please see the study for all other authors’ relevant financial disclosures.