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Drug-Eluting Stents Beat Bare-Metal in STEMI Patients

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New Stents "First Choice" for STEMI

By their very nature, the biodegradable polymers used in newer generation DESs might offer the early advantages of polymers – protecting against stent thrombosis – while avoiding the very late hazards, their proinflammatory and prothrombotic effects. This may turn out to be especially useful in patients with STEMI.

Although COMFORTABLE AMI is a well done trial with convincing results, it has neither the required sample size nor the sufficient length of follow-up to provide the definitive answer about the long-term safety of the new biodegradable DES in this setting. Nonethelesss, the trial offers positive signals that, along with previous findings indicating the excellent 4-year safety of biodegradable polymer DESs, form a good basis to believe that these new DESs may belong to the "first-choice" devices in patients with STEMI.

The findings from the COMFORTABLE AMI trial and from previous trials on DESs in patients with AMI show that the efficacy of DESs versus BMSs in STEMI is already established, therefore there is almost no rationale any more for performing studies comparing a DES with a BMS.

It is also now apparent that concerns about a possible very late safety issue with DESs are apparently specific to the stent type and are mostly related to first-generation DESs. Such concerns are less justified with newer DESs.

Dr. Salvatore Cassese and Dr. Adnan Kastrati are with Deutsches Herzzentrum,Technische Universitat, Munich. These remarks are taken from their editorial accompanying the COMFORTABLE-AMI report (JAMA 2012;308:814-5). Dr Kastrati holds a patent related to polymer-free sirolimus and probucol coating and reported receiving honoraria from Abbott, Biosensors, Cordis, and Medtronic. Dr Cassese reports no conflicts.


 

FROM JAMA

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.

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