• Cardiology Clinical Trials
• Interventional Techniques & Devices
• Myocardial Infarction

For patients with acute ST elevation myocardial infarction (STEMI), outcomes with percutaneous coronary intervention (PCI) using a new-generation drug-eluting stent (DES) were similar after 1 year compared with a bare-metal stent (BMS), according to new findings from the Evaluation of Xience V Stent in Acute Myocardial Infarction trial [EXAMINATION; NCT00828087].

Manel Sabaté, MD, University Hospital Clinic, Barcelona, Spain, presented results from the multinational EXAMINATION study.

EXAMINATION included 1504 patients who presented with STEMI within 48 hours of symptom onset. All patients required emergent PCI and were required to have a target vessel diameter of 2.25 to 4.0 mm to accommodate currently available stents. The “all-comer” trial design resulted in a study population that was highly representative of real-world patients who are undergoing PCI for acute STEMI. The study enrolled 70% of all STEMI patients who presented to 12 study sites in Spain, Italy, and The Netherlands, including patients who presented within 12 hours of symptom onset (primary PCI), after successful thrombolysis, after failed thrombolysis (rescue PCI), and between 12 and 48 hours of symptom onset (latecomers).

Patients were randomly assigned, in a single-blind fashion, to intervention with an everolimus-eluting stent (EES; n=751) or a cobalt-chromium stent (n=747). Baseline and procedural characteristics were similar in the two treatment groups, including good compliance with antithrombotic medications at discharge and throughout the 1-year follow-up period (approximately 90% was on dual antiplatelet therapy [DAPT] at 1 year). Acute procedure-related outcomes were similar in the DES and BMS groups, with a low risk of TIMI bleeding and very low rate of device malfunction (0.5% vs 0.7%; p=NS). The primary composite endpoint was all-cause death, myocardial infarction (MI), and revascularization. The trial, as designed, had 86% power to detect a 30% reduction in the rate of the primary endpoint at 1 year for DES compared with BMS.

After 1 year, a similar proportion of patients in the DES and BMS groups remained free from the primary endpoint (87.8% vs 85.7%; p=0.20). Several individual endpoints were also similar, including freedom from cardiac death (96.7% vs 97.1%; p=0.68), recurrent MI (98.6% vs 97.9%; p=0.30), and repeat revascularization (91.6% vs 89.2%; p=0.10).

Although the comparison of the primary endpoint was neutral, there were reductions in key secondary endpoints with DES compared with BMS, including reductions in the rates of definite or probable stent thrombosis (0.9% vs 2.6%; p=0.01) and definite stent thrombosis (0.5% vs 1.9%; p=0.01).

The results of this study support the 2010 European Society of Cardiology guideline preference for DES over BMS in patients who have no contraindications to prolonged DAPT. More specifically, the findings of the EXAMINATION trial are consistent with the existing literature that demonstrates the safety and efficacy of DES for use in patients with STEMI. A particular strength of this study is the inclusion of all-comer STEMI patients, resulting in a cohort that is generalizable to clinical practice. In addition, it is one of the first trials that have evaluated EES, a newer-generation DES, in such a broad population.

The observation of a reduction in definite and definite or probable stent thrombosis in this modestly powered single-blind trial requires validation. In applying results to clinical practice, it should be noted that there was high utilization (90%) of DAPT through 1 year.

• © 2011 MD Conference Express