Lipoprotein associated- phospholipase A2 in STEMI vs. NSTE-ACS patients: a marker of cardiovascular atherosclerotic risk rather than thrombosis

The precise role of Lipoprotein associated phospholipase A2 (Lp-PlA2) in the pathogenesis of acute coronary syndromes (ACS) and in the prediction of future cardiovascular events is still debated. So far, few data exist on the variations of Lp-PlA2 activity in ACS and especially in NSTE-ACS vs. STEMI patients, where thrombotic and atherosclerotic mechanisms could play a differential role. The aim of the present study was, then, to compare Lp-PlA2 activity according to the type of ACS presentation. Methods: A consecutive cohort of patients undergoing coronary angiography for acute coronary syndrome (ACS) were included and divided according to presentation for non ST-segment elevation-ACS or ST-segment elevation Myocardial Infarction (STEMI). Lp-PLA2 activity was assessed in blood samples drawn at admission using the Diazyme Lp-PlA2 Activity Assay. Results: We included in our study 117 patients, of whom 31 (26.5%) presented with STEMI. STEMI patients were significantly younger (p = 0.05), displayed a lower rate of hypertension (p = 0.002), previous MI (p = 0.001) and PCI (p = 0.01) and used less frequently statins (p = 0.01) and clopidogrel (p = 0.02). White blood cells and admission glycemia were increased in STEMI (p = 0.001, respectively). The prevalence and severity of CAD was not different according to ACS types, but for a higher prevalence of thrombus (p < 0.001) and lower TIMI flow (p = 0.002) in STEMI. The levels of Lp-PlA2 were significantly lower in STEMI as compared to NSTE-ACS patients, (132 +/- 41.1 vs. 154.6 +/- 40.9 nmol/min/mL, p = 0.01). In fact, the rate of patients with Lp-PlA2 above the median (148 nmol/min/mL) was significantly lower in STEMI patients as compared to NSTE-ACS (32.3% vs. 57%, p = 0.02, adjusted OR[95% CI] = 0.20[0.06-0.68], p = 0.010). Moreover, a direct linear relationship was observed between Lp-PlA2 and LDL-C (r = 0.47, p < 0.001), but not with inflammatory biomarkers. Conclusion: The present study shows that among ACS patients, the levels of Lp-PlA2 are inversely associated with STEMI presentation and thrombotic coronary occlusion, being instead increased in NSTE-ACS patients, therefore potentially representing a marker of more aggressive chronic cardiovascular disease with an increased risk of recurrent cardiovascular events.