Bernelin H, et al. – Researchers investigated whether neprilysin (NEP) plasma levels following reperfusion may be a surrogate for infarct size (IS) or predict adverse outcomes in acute ST-segment elevation myocardial infarction (STEMI) in a prospective cohort of 203 patients with STEMI referred for primary percutaneous coronary intervention. In a subset of 21 patients, circulating soluble NEP was measured at admission (t0) and 4 hours later (t4) following reperfusion, and on 7 times points (t0, t4, t12, t24, t48, day 7, and day 30). Using cardiac magnetic resonance, IS and left ventricular ejection fraction were measured at 1 month. Participants were followed-up for 12-months to report adverse cardiovascular outcomes. Findings revealed widely distributed NEP serum levels and no significant change in these levels was observed in the first hours and 1-month period post-reperfusion in STEMI patients. NEP serum levels had no significant association with markers of infarct size and inflammation, and 1-year adverse outcomes.