Cardiology Update: Examination trial

In patients with Acute Myocardial Infarction, where the entire focus boils down to the management of thrombus, rather than management of the vessel-valves, it becomes important to ascertain what kind of stents should one use in such an emergency. There is little long-term follow-up data available, on the safety as well as the efficacy of new generation drug-eluting stents in the setting of ST-elevation MI.

In a such setup,a multi-center EXAMINATION trial studied as well as compared Everolimus-eluting Stents (EES) with bare-metal stents in an all-comer population with STEMI . Recently the 5 year outcome this trial were published.

A total of 1498 STEMI patients were randomly assigned to receive either EES (Xience V, Abbott Vascular) or a cobalt-chromium BMS (Multilink Vision, Abbott Vascular). Five-year follow-up data was complete in 97% of both groups.

At 5 years, the combined device-driven outcome of cardiac death, target vessel MI, and target lesion revascularization favored EES ( 21%) over BMS (26%).

The researcher concluded that in patients with STEMI who underwent primary PCI, durable polymer-based EES were superior to BMS for both patient-oriented and device-oriented endpoints at 5 years.

“Our findings should be taken as a point of reference for the assessment of new bioresorbable polymer-based metallic stents or bioresorbable scaffolds in patients with ST-segment elevation myocardial infarction,” wrote the authors.

Critical comment

Yet Critically evaluating comments pointed to the low statistical of this trial.

"The simple conclusion that EES reduce mortality compared with BMS because of benefits that become apparent in the long term is tempting, but cannot be accepted so simply in view of the low statistical power of EXAMINATION, the unclear mechanisms at play, and that most of the events that might be expected to be directly or indirectly linked to mortality were significantly reduced by EES only during the first year (i.e., stent thrombosis and revascularization) or were distributed in the opposite direction between 1 year and 5 years (i.e., myocardial infarction),” wrote editorialist D Capodanno. Rather, these late-term results suggest no signals of late attrition with EES or accrued safety hazards compared to BMS.