Soluble endothelial protein C receptor levels and protein C activity in patients with acute ST-segment elevation myocardial infarction

OBJECTIVES: In contrast to its membrane-bound form, soluble endothelial protein C receptor (sEPCR) expresses procoagulant activity through binding to protein C. We aimed to investigate the relationship between sEPCR levels and protein C activity in patients with ST-segment elevation myocardial infarction (STEMI). METHODS: The study population included 60 STEMI patients who had undergone a primary percutaneous coronary intervention and 29 patients with stable angina pectoris (SAP) with significant coronary stenosis on angiography. Preprocedural sEPCR levels and protein C activity were determined in all study patients. RESULTS: In the STEMI group, the baseline sEPCR level was significantly higher (172.0±89.3 vs. 107.1±39.2 ng/ml, P<0.001) and protein C activity was significantly lower (91.9±26.4 vs. 124.5±16.2%, P<0.001) compared with patients with SAP. There was a significant negative correlation between protein C activity and sEPCR in the STEMI group (r=-0.38, P=0.002); however, no significant correlation was observed in the SAP group (r=0.02, P=0.91). Angiographic thrombus load and the incidence of no-reflow phenomenon were significantly higher in STEMI patients with protein C activity under the median level. CONCLUSION: The ratio of sEPCR levels to protein C activity is high, with a significant negative correlation in patients with STEMI. Lower protein C activity is associated with the development of no-reflow in STEMI patients. However, the sEPCR level has no relation to the development of no-reflow. The clinical significance of elevated sEPCR level in STEMI should be evaluated in larger studies.