EXAMINATION trial shows superiority of second generation drug-eluting stent at five years

The EXAMINATION trial has demonstrated the superiority of a second generation drug-eluting stent over a bare-metal stent at five years in research presented at ESC Congress.

"This is the first time since primary percutaneous coronary intervention (PCI) demonstrated superiority over thrombolysis that a device (stent) has shown clinical benefit beyond restenosis prevention in a randomised well powered trial in ST-segment elevation myocardial infarction (STEMI)," said principal investigator Dr Manel Sabaté, cardiologist at the Hospital Clinic de Barcelona in Spain.

Until now, no data has been available on the safety and efficacy of newer generation drug-eluting stents at long-term follow-up. The multicentre, multinational, prospective, randomised, single-blind, controlled EXAMINATION trial compared the performance of everolimus-eluting stents (EES) versus bare-metal stents (BMS) in an all-comer STEMI population.

The trial included 1 498 patients with STEMI requiring primary PCI who were randomly assigned in a 1:1 ratio to receive EES (751 patients) or BMS (747 patients) between 2008 and 2010. The primary endpoint was the patient-oriented combination of all-cause death, any recurrent myocardial infarction and any revascularization.

EXAMINATION was one of the first trials to use this combined endpoint, as recommended by the Academic Research Consortium (ARC). At one year and at two year follow-up, the patient-oriented endpoint was comparable between stent groups. However, the need for repeat revascularization and, for the first time, stent thrombosis rate was reduced by the second generation drug-eluting stent.

The findings presented for the first time today at ESC Congress are the five year outcomes. Complete five year clinical follow-up was obtained in more than 97% of patients. Baseline clinical and procedural characteristics were comparable between both groups. A total of 153 deaths, 62 recurrent myocardial infarctions, 209 revascularizations and 35 definite/probable stent thrombosis episodes occurred during the five year follow-up.

The primary endpoint was significantly reduced in the EES group (21.6±1.5% vs. 26.0±1.6%; p=0.03). Similarly, the device-oriented composite endpoint of cardiac death, target vessel myocardial infarction and target lesion revascularization was significantly reduced by EES (11.9%±1.2% vs. 15.5±1.3%; p=0.04). Definite/probable stent thrombosis rate was non-significantly reduced in the EES group (2.1±0.5% vs. 3.1±0.6%; p=0.17).

"The five year follow-up of the EXAMINATION trial has demonstrated clinical superiority of the everolimus-eluting stent over a bare-metal stent in the patient-oriented primary endpoint, accomplishing the hypothesis of the trial," said Dr Sabaté. "Our findings help to dispel worries that the early clinical benefits of drug-eluting stents in patients with STEMI may vanish over time because of late hazards including stent thrombosis and repeat revascularization due to neoatherosclerosis or restenosis."

He concluded: "These results lay the foundation for future developments in stent technologies for primary PCI in patients with STEMI. Long-term outcomes of EES in this clinical scenario should be taken as reference for the evaluation of new bioresorbable polymer-based metallic stents or bioresorbable scaffolds."