Use of biolimus-eluting stents with a biodegradable polymer resulted in a significantly lower major adverse cardiac event rate at 1 year than did use of bare-metal stents in patients with acute myocardial infarction who were undergoing primary percutaneous coronary intervention.
The finding comes from Comparison of Biolimus Eluted From an Erodible Stent Coating With Bare Metal Stents in Acute ST-Elevation Myocardial Infarction (COMFORTABLE AMI), a multicenter, randomized, assessor-blinded, superiority trial in patients presenting with STEMI who were undergoing primary PCI. The trial of more than 1,100 patients found that compared with the use of bare-metal stents, the use of biolimus-eluting stents with a biodegradable polymer was associated with a significant 4.4% absolute reduction and 51% relative reduction in the risk of major adverse cardiac events at 1 year. Use of the biolimus-eluting stents prevented 42 events per 1,000 patients at 1 year compared with bare-metal stents, said Dr. Lorenz Raber of Bern (Switzerland) University Hospital and his associates (JAMA 2012;308:777-87).
The final analysis included 575 patients with 629 infarct vessel lesions randomly assigned to biolimus-eluting stents (Bio-Matrix, Biosensors Europe SA) and 582 patients with 648 infarct-vessel lesions randomly assigned to otherwise identically designed bare-metal stents (Gazelle, Biosensors Europe SA). The patients had a mean age of 61 years, and 79% were men. The median time from symptom onset to balloon inflation was 234 minutes, and from hospital admission to balloon inflation, 44 minutes. There were no apparent differences in lesion complexity between the two groups.
At discharge, 43% of patients received prasugrel and 57% of patients received clopidogrel. In contrast with most previous trials of patients with STEMI, the use of dual antiplatelet therapy remained balanced in both treatment groups throughout the entire follow-up period up to 1 year, the investigators noted.
At 1 year, the primary end point of major adverse cardiac events (cardiac death, target vessel–related reinfarction, and ischemia-driven target-lesion revascularization) occurred in 4.3% of patients who received biolimus-eluting stents and 8.7% of patients given bare-metal stents, producing a hazard ratio of 0.49 (P = .004). For cardiac death alone, the percentages were 2.9% with biolimus-eluting stents and 3.5% for bare-metal stents (HR 0.81, P = .53).
The treatment effect in favor of patients receiving biolimus-eluting stents was attributable to significantly lower risks of target vessel–related reinfarction (0.5% vs 2.7% HR, 0.20, P =.01) and ischemia-driven target-lesion revascularization (1.6% vs 5.7%, HR 0.28). Differences between stent types with respect to the primary outcome emerged early and continued throughout the study period, Dr. Raber and his associates said.
The rates of definite stent thrombosis at 1 year did not differ significantly, at 0.9% in patients receiving biolimus-eluting stents and 2.1% in those receiving bare-metal stents. Furthermore, no differences were seen in all-cause and cardiac mortality between the groups at 1 year.
The biolimus-eluting stent used in this study is not approved by the Food and Drug Administration, but data showing that it was noninferior to the sirolimus-eluting Cypher stent (Lancet 2011;378:1940-8) provided the basis for a recommendation for its use in European guidelines on myocardial revascularization (Eur. Heart J. 2010;31:2501-5), they noted.
The COMFORTABLE AMI trial was investigator-initiated, managed by the Clinical Trials Unit, University of Bern (Switzerland), and supported by the Swiss National Science Foundation and an unrestricted research grant from Biosensors Europe SA, Morges, Switzerland. Dr. Raber is the recipient of a research fellowship funded by the Swiss National Science Foundation.