October 1, 2018—Findings from the ABSORB IV randomized trial demonstrated that the polymeric Absorb bioresorbable vascular stent (BVS; Abbott Vascular) implanted with optimized technique in an expanded patient population resulted in noninferior 30-day and 1-year rates of target lesion failure and angina compared with a metallic drug-eluting stent (DES).

Gregg W. Stone, MD, presented the data at TCT 2018, the 30th Transcatheter Cardiovascular Therapeutics annual scientific symposium held September 21–25 in San Diego, California. The study was simultaneously published online ahead of print by Dr. Stone et al in The Lancet.

The investigators noted that in earlier comparisons of coronary BVS and metallic DES, the studies were unmasked, lesions smaller than intended for the scaffold were frequently enrolled, implantation technique was suboptimal, and patients with myocardial infarction—in whom BVS might be well suited—were excluded.

As summarized in The Lancet, ABSORB IV is an active-controlled, blinded, multicenter, randomized trial composed of patients with stable coronary artery disease or acute coronary syndromes who were18 years or older and were recruited at 147 hospitals in five countries (United States, Germany, Australia, Singapore, and Canada). Enrolled patients were randomly assigned (1:1) to receive an Absorb BVS with optimized implantation technique or a DES (Xience cobalt-chromium everolimus-eluting stent, Abbott Vascular).

Randomization was stratified by diabetic status, site, and whether patients would have been eligible for enrollment in the previous ABSORB III trial. Patients and clinical assessors were masked to randomization.

The primary endpoint was target lesion failure (cardiac death, target vessel myocardial infarction, or ischemia-driven target lesion revascularization) at 30 days, tested for noninferiority with a 2.9% margin for the risk difference. Analysis was by intention to treat.

The investigators reported:

• The study enrolled 2,604 patients of 18,722 patients screened for eligibility between August 15, 2014, and March 31, 2017.
• The study randomly assigned 1,296 patients to BVS and 1,308 patients to DES.
• Thirty-day follow-up data were available for 1,288 patients with BVS and 1,303 patients with DES.
• One-year follow-up data were available for 1,254 patients with BVS and 1,272 patients with DES.
• Biomarker-positive acute coronary syndromes were present in 622 of 2,602 (24%) patients.
• Seventy-eight of 2,893 (3%) lesions were in very small vessels, as assessed by angiographic core laboratory analysis.

The ABSORB IV findings included the following:

• Target lesion failure at 30 days occurred in 64 (5%) patients assigned to BVS and 48 (3.7%) patients assigned to DES (difference, 1.3%; upper 97.5% confidence limit, 2.89; one-sided P_{noninferiority} = .0244).
• Target lesion failure at 1 year occurred in 98 (7.8%) patients assigned to BVS and 82 (6.4%) patients assigned to DES (difference, 1.4%; upper 97.5% confidence limit, 3.4; one-sided P_{noninferiority} = .0006).
• Angina (adjudicated by a central events committee at 1 year) occurred in 270 (20.3%) patients assigned to BVS and 274 (20.5%) patients assigned to DES (difference, –0.3%; 95% confidence interval, –3.4% to 2.9%; one-sided P_{noninferiority} = .0008; two-sided P_superiority = .8603).
• Device thrombosis within 1 year occurred in nine (0.7%) patients assigned to BVS and four (0.3%) patients assigned to DES (P = .1586).