Elevated Carbonylated Proteins Are Associated with Major Cardiovascular Events in Patients with Chronic Coronary Syndrome: A Cohort Study

BACKGROUND:Protein carbonylation is reported in atherosclerosis, but its predictive value is unknown. AIMS:We evaluated plasma carbonylated protein (PC) levels in association with clinical outcomes in coronary artery disease (CAD) in long-term follow-up. METHODS:In patients with advanced stable CAD, we assessed plasma PC content along with fibrin clot properties, i.e., permeability (Ks) and clot lysis time, and its determinants: plasminogen activator inhibitor-1 (PAI-1) and thrombin-activatable fibrinolysis inhibitor. We recorded a composite of myocardial infarction, ischemic stroke, systemic embolism, and cardiovascular death during a follow-up of 8.3 (1.8) years. RESULTS:The analysis involved 178 patients aged 64.0 (57.0-70.0) years. The baseline PC content was 2.9 (2.2-3.7) nmol/mg protein and was elevated above the reference value obtained for a control group (2.03 nmol/mg protein) in 82.6% of patients. In linear regression models, high PC adjusted for age was associated with lower Ks, longer clot lysis time, and elevated PAI-1 and thrombin-activatable fibrinolysis inhibitor. Baseline PC was 48% higher in patients with the composite endpoint (n = 67, 37.6%) compared with others (P <0.001). Patients with PC in the highest quartile (3.7-5.1 nmol/mg protein) were more likely to develop the composite endpoint compared to the lowest quartile (hazard ratio [HR] 4.9; 95% confidence interval, 2.1-11.3; P <0.001). CONCLUSIONS:This is the first study showing that in CAD the extent of protein carbonylation, in part via its antifibrinolytic effects, predisposes to cardiovascular events in long-term follow-up, highlighting the role of persistent oxidative protein modifications in atherosclerotic vascular disease.