Abstract 18281: Soluble Form of Membrane Attack Complex Independently Predicts Mortality and Cardiovascular Events in Patients with ST-segment Elevation Myocardial Infarction

Background: The complement system is an important mediator of inflammation, which plays a pivotal role in atherosclerosis and acute myocardial infarction (AMI). Animal studies suggest that activation of the complement cascade resulting in the formation of sMAC, contributes to both atherosclerosis and plaque rupture and may be the direct cause of tissue damage related to ischemia/reperfusion injury. However clinical data of sMAC during an AMI is sparse. Accordingly the aim was to investigate the prognostic role of soluble membrane attack complex (sMAC) in patients with ST-segment elevation myocardial infarction (STEMI). Methods: We included 725 STEMI-patients admitted to a single, high-volume invasive heart centre, treated with primary percutaneous coronary intervention (PCI), from September 2006 to December 2008. Blood samples were drawn immediately before PCI. Plasma sMAC was measured using an in-house immunoassay. Endpoints were all-cause mortality (n=62) and the combined endpoint (n=122) of major cardiovascular events (MACE) defined as cardiovascular mortality and admission due recurrent AMI or heart failure. Follow-up time was 12 months. Results: Patients with high sMAC (>75 th percentile) had increased risk of all-cause mortality and MACE. Even after adjustment for confounding risk factors by Cox-regression analyses, high levels of sMAC remained an independent predictor of all-cause mortality (hazard ratio 1.81 (95% CI 1.06-3.06; p=0.029)) and MACE (hazard ratio 1.70 (95% CI 1.16-2.48; p=0.006)). Conclusions: High plasma sMAC independently predicts all-cause mortality and MACE in STEMI-patients treated with PCI.