Apelin: a novel marker for the patients with first ST-elevation myocardial infarction.

To date, only animal studies have been concerned with apelin involvement in acute myocardial ischemia. The aim of this study was to investigate apelin measurements in low-risk patients with first ST-elevation myocardial infarction (STEMI) and to assess if apelin may feature as a marker of left ventricular (LV) injury and prognosis. In 78 consecutive patients (mean age 67 +/- 11.5 years, 24 women) with first STEMI treated with primary percutaneous coronary intervention, plasma apelin-36 concentrations were measured twice: on admission and on the 5th day of hospitalization. Left ventricle ejection fraction (LVEF) was applied as marker of LV injury. Composite endpoint (CEP), which included death, stroke, and recurrent ischemic event, was assessed after 1 year follow-up. On the first day, median apelin-36 concentration was 2138.5 pg/ml and on the 5th day was significantly lower, 2008.3 pg/ml (P = 0.002). There were no significant differences found in apelin-36 concentrations between patients with normal and low LVEF. In both groups significant reductions were found in apelin-36 concentrations measured in 5-day intervals (P = 0.04 and P = 0.008, respectively). After a 1-year follow-up, only one patient died and 19 patients (24.3%) had reached CEP. No difference in baseline apelin-36 concentrations were found in the group of patients who reached CEP compared with those without CEP. However, in both groups concentrations significantly decreased after 5 days (P = 0.04 and P = 0.013, respectively). Apelin-36 concentrations are reduced in low risk first STEMI patients during the first days regardless of the degree of LV dysfunction and prognosis.