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ABSORB II: BVS Yields Comparable Clinical Results vs. Metallic Stent at 2 Years
At 2 years, an everolimus-eluting bioresorbable scaffold appears to yield comparable outcomes vs. a metallic stent in treating patients with ischemic heart disease, according to results from the ABSORB II trial.
The rates of a patient-oriented composite endpoint, a device-oriented composite endpoint, target lesion failure, MACE and target vessel failure were similar between the two technologies, according to the researchers.
In the prospective, randomized, active-controlled, single blind, multicenter trial, researchers evaluated 501 patients with ischemic heart disease caused by de novo native coronary artery lesions. Participants were randomly assigned 2:1 to undergo treatment with a bioresorbable vascular scaffold (BVS; Absorb, Abbott Vascular; n = 335; mean age, 61.5 years; 75.5% men) or a metallic everolimus-eluting stent (Xience, Abbott Vascular; n = 166; mean age, 60.9 years; 79.5% men). Patients were scheduled to be seen for clinical follow-up at 30 and 180 days, and at 1, 2, 3, 4 and 5 years. Coronary angiography, IVUS, and IVUS virtual histology imaging were scheduled for before and after device implantation, as well as 3 years after index procedure. An independent clinical events committee adjudicated all MACE.
At 2 years, the researchers compared the groups in terms of a patient-oriented composite endpoint (all-cause mortality, MI or revascularization), a device-oriented composite endpoint (cardiac death, target vessel MI or ischemia-driven target lesion revascularization), TLF, MACE and TVF. At 2 years, 480 patients underwent clinical follow-up.
No differences
The researchers found no difference between the groups in the 2-year composite rate of MACE (7.6% in the BVS arm vs. 4.3% in the Xience arm; RR = 1.79; 95% CI, 0.79-4.04). Additionally, no statistically significant differences were seen between the groups in device-oriented composite endpoint (7% in the BVS arm vs. 3% in the metallic arm; RR = 2.3; 95% CI, 0.89-5.94); results were also similar in the device endpoint plus TLF (RR = 1.71; 95% CI, 0.47-6.2). The rate of TVF was 8.5% in the BVS group vs. 6.7% in the metallic group (RR = 1.27; 95% CI, 0.65-2.49).
Similar rates also were seen between the two cohorts in the patient-oriented composite endpoint (11.6% in the BVS arm vs. 12.8% in the metallic arm; RR = 0.9; 95% CI, 0.55-1.49). The rates of definite or probable scaffold or stent thrombosis were 1.5% in the BVS arm vs. 0% in the metallic arm (P = .174).
At 2 years, 36% of patients in the BVS arm vs. 34% of patients in the metallic arm remained on dual antiplatelet therapy (P = .677). In both arms, 92.2% of patients remained on an aspirin regimen at 2 years.
Event rates low
“In the randomized ABSORB II trial comparing a bioresorbable scaffold and a metallic stent, the 2-year clinical results did not differ between the two arms and demonstrated low rates of clinical events, such as patient-oriented endpoints, in both arms,” the researchers wrote. “The rare occurrence of very late scaffold thrombosis events warrants further investigation.” – by Jennifer Byrne
Disclosure: The study was funded by Abbott Vascular. Some researchers report financial ties with Abbott Vascular.