Role of ST-Segment Resolution in Patients With ST-Segment Elevation Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention (from the 5-Year Outcomes of the EXAMINATION [Evaluation of the Xience-V Stent in Acute Myocardial Infarction] Trial)

In patients with ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (pPCI), lack of ST-segment resolution (STR) is associated with poor prognosis at short- and long-term follow-up. The aim of this study was to evaluate the role of STR on very long-term outcomes in patients with STEMI treated with pPCI included in the EXAMINATION (Evaluation of the Xience-V Stent in Acute Myocardial Infarction) trial. Patients were stratified according to the presence of STR < 50% and STR < 70% at the 30-minute post-pPCI electrocardiogram. Primary end point was the patient-oriented composite endpoint (POCE) of all-cause death, any myocardial infarction, or any revascularization at 5-year follow-up. Both baseline and post-PCI 30-minute electrocardiograms were available for STR assessment in 1,351 patients. Of these patients, 228 (16.9%) and 500 (37.0%) exhibited STR < 50% and STR < 70%, respectively. At 5-year follow-up, the POCE was observed more frequently in patients with STR < 50% (hazard ratio [HR] 1.556; 95% confidence interval [CI] 1.194 to 2.027; p <0.001) and in patients with STR < 70% (HR 1.460, 95% CI 1.169 to 1.824, p <0.001) compared with patients with STR > 50% and STR ≥ 70%, respectively. In both cases, this difference was mainly driven by a significant increase in the rate of all-cause death and any revascularization. After multivariable adjustment, STR < 70%, but not STR < 50%, resulted as a 5-year independent predictor of POCE (adjusted HR 1.338, 95% CI 1.008 to 1.778, p = 0.044). In conclusion, in patients with STEMI, the evaluation of 70% STR after pPCI provides independent prognostic information at 5-year follow-up and it can be used to identify patients at high risk of very long-term cardiovascular events.