Thrombin generation during reperfusion after coronary artery bypass surgery associates with postoperative myocardial damage

"Background: Cardiopulmonary bypass and coronary artery bypass grafting (CABG) result in significant thrombin generation and activation of fibrinolysis. Thrombin contributes to myocardial ischemia-reperfusion injury in animal studies, but the role of thrombin in myocardial damage after CABG is unknown. Objectives: We measured thrombin generation and fibrin turnover during reperfusion after CABG to evaluate their associations with postoperative hemodynamic changes and myocardial damage. Methods: One hundred patients undergoing primary, elective, on-pump CABG were prospectively enrolled. Plasma prothrombin fragment F1+2 and D-dimer were measured preoperatively and at seven time points thereafter. Mass of the Mb fraction of creatine kinase (Ck-Mbm) and troponin T (TnT) were measured on the first postoperative day. Results: Reperfusion induced an escalation of thrombin generation and fibrin turnover despite full heparinization. F1+2 during early reperfusion associated with postoperative pulmonary vascular resistance index. F1+2 at 6 h after protamine administration correlated with Ck-Mbm (r = 0.40, P < 0.001) and TnT (r = 0.44, P < 0.001) at 18 h postoperatively. Patients with evidence of myocardial damage (highest quintiles of plasma Ck-Mbm and TnT) had significantly higher F1+2 during reperfusion than others (P < 0.002). Logistic regression models identified F1+2 during reperfusion to independently associate with postoperative myocardial damage (odds ratios 2.5-4.4, 95% confidence intervals 1.04-15.7). Conclusions: Reperfusion caused a burst in thrombin generation and fibrin turnover despite generous heparinization. Thrombin generation during reperfusion after CABG associated with pulmonary vascular resistance and postoperative myocardial damage."