Apelin in ST segment elevation and non-ST segment elevation acute coronary syndromes: a novel finding

Background: Apelin is a novel endogenous peptide with inotropic and vasodilatory properties. Aim: To investigate the role of apelin in the prognosis of acute coronary syndromes (ACS) and to assess the relationship between apelin and other diagnostic and prognostic markers. Methods: Seventy-six patients with ACS (mean age 62.1 ± 10 years) were evaluated in terms of their plasma apelin-36 concentrations, ejection fraction (EF), high sensitivity C-reactive protein (hsCRP), creatine kinase (CK), CK-MB and troponin I levels. The study group consisted of 35 ST elevation myocardial infarction (STEMI) and 41 non-ST elevation (NSTE) ACS patients. Patients were followed up for one year for cardiovascular outcomes. Results: There was no significant relationship between apelin and TIMI, GRACE, GENSINI scores, hsCRP and EF in STEMI and NSTE-ACS groups (p > 0.05). Apelin showed positive correlations with CK, CK-MB and troponin I in patients with NSTE-ACS, but a negative correlation in patients with STEMI (p < 0.05). There were no statistically significant differences between patients reaching the composite end point at one year with regard to apelin levels. Conclusions: Apelin was positively correlated with cardiac biomarkers in patients with NSTE-ACS but negatively correlated in patients with STEMI. In STEMI, generally larger amounts of myocardial cells are subjected to infarction compared to NSTE-ACS, which may explain why apelin levels decrease with increasing CK, CK-MB and troponin levels in STEMI patients.