BACKGROUND - The prognostic significance of periprocedural myocardial infarction (MI) remains controversial.

METHODS AND RESULTS - The study aims to investigate the incidence of periprocedural MI in the era of high sensitivity diagnostic markers and intense antithrombotics, and its impact on early outcomes of patients with acute MI treated with primary angioplasty (pPCI). Data from the PRAGUE-18 (prasugrel versus ticagrelor in pPCI) study were analyzed. The primary net-clinical endpoint (EP) included death, spontaneous MI, stroke, severe bleeding, and revascularization at day 7. The key secondary efficacy EP included cardiovascular death, spontaneous MI, and stroke within 30 days. The incidence of peri-pPCI MI was 2.3% (N = 28) in 1230 study patients. The net-clinical EP occurred in 10.7% of patients with, and in 3.6% of patients without, peri-pPCI MI (HR 2.92; 95% CI 0.91-9.38; P = 0.059). The key efficacy EP was 10.7% and 3.2%, respectively (HR 3.44; 95% CI 1.06-11.13; P = 0.028). Patients with periprocedural MI were at a higher risk of spontaneous MI (HR 6.19; 95% CI 1.41-27.24; P = 0.006) and stent thrombosis (HR 10.77; 95% CI 2.29-50.70; P = 0.003) within 30 days. Age, hyperlipidemia, multi-vessel disease, post-procedural TIMI <3, pPCI on circumflex coronary artery, and periprocedural GP IIb/IIIa inhibitor were independent predictors of peri-pPCI MI.

CONCLUSIONS - In the era of intense antithrombotic therapy, the occurrence of peri-pPCI MI is despite highly sensitive diagnostic markers a rare complication, and is associated with an increased risk of early reinfarction and stent thrombosis.