Serum secretory phospholipase A2-IIa (sPLA2-IIA) levels in patients surviving acute myocardial infarction

BACKGROUND: The increase of secretory phospholipase A2-IIa (sPLA2-IIa) in culprit coronary lesions is associated with myocardial infarction, and the increase of sPLA2-IIa in peripheral plasma levels has a significant risk and prognostic value in patients with coronary artery disease. Little is known about the prognostic significance of elevated serum sPLA2-IIa in post-acute myocardial infarction (post-AMI) patients. OBJECTIVES: The present study is designed to investigate the potential association between serum sPLA2-IIa and prognosis in post-acute myocardial infarction (post-AMI) patients. PATIENTS AND METHODS: From Oct 1998 to Sep 2008, a total of 964 post-AMI patients with serum samples collected in the convalescent stage were studied. Serum levels of sPLA2-IIa were measured by ELISA. According to the optimal cut-off value for sPLA2-IIa concentration, patients were then divided into 2 groups. Categorical variables were compared between the 2 groups using the chi(2) test. All continuous variables are described as mean +/- SD and were compared using Student's t-test. Statistical associations between clinicopathological observations and sPLA2-IIa levels were determined using the Mann-Whitney U test. The clinical value of sPLA2-IIa level as a prognostic parameter was evaluated using the Cox's proportional hazards model. RESULTS: During a median follow-up period of 1,462 days, 123 patients (12.7%) had adverse events (all-cause mortality, n = 52; non-fatal MI, n = 31; readmission for heart failure [HF], n = 40). Patients were divided into 2 groups according to a serum sPLA2-IIa level of 360 ng/dl, which was determined to be the optimal cut-off for discriminating all-cause mortality based on the maximum value of the area under the receiver operating characteristic curve. Patients with elevated sPLA2-IIa (> 360 ng/dl, n = 164) had a significantly higher prevalence of death (18.3% [30/164] vs. 2.75% [22/800] p < 0.001) and readmission for HF (14% [23/164/ vs. 2.1% [17/800], p < 0.0001), but not of non-fatal MI (4.88% [8/164] vs. 2.87% [23/800], p = 0.096), compared to those with sPLA2-IIa < 360 ng/dl. Multivariate Cox regression analysis indicated that elevated serum sPLA2-IIa was associated with an increased risk of mortality and readmission for HF. CONCLUSIONS: Elevated serum sPLA2-IIa during the convalescent stage of AMI predicted long-term mortality and readmission for HF after survival discharge in the post-AMI patients.