Quantitative and temporal differences in coagulation, fibrinolysis and platelet activation after on-pump and off-pump coronary artery bypass surgery

Background: With the increasing use of OPCAB, potentially devastating thromboembolic events, including graft thrombosis may become increasingly evident. We present a study of the quantitative and temporal differences of the coagulation system, fibrinolysis and platelet activation after coronary artery surgery with or without cardiopulmonary bypass. Methods: Patients undergoing on-pump CABG (n = 10) or OPCAB (n = 10) had six blood samples taken before surgery and up to 24 h post-operatively. Activation of the coagulation cascade (tissue factor pathway-factor VIIa), endothelial injury (von Willebrand Factor antigen), thrombin generation (prothrombin fragments FI + II), fibrinolysis (decreased plasminogen levels), fibrin degradation (D-Dimer), platelet counts and platelet activation (soluble P-selectin) were quantified. Results: CABG caused earlier and more significant generation of thrombin, however OPCAB caused a late and sustained generation of thrombin. CABG caused intraoperative activation of fibrinolysis and fibrin degradation, however, at 24 h these parameters were equally elevated in both groups. Platelet activation was significant in the CABG group, but did not occur in the OPCAB group. Conclusions: Late thrombin generation and reduced fibrinolysis in the presence of intact, functioning platelets may contribute to adverse thromboembolic events after OPCAB surgery. Thromboembolic prophylaxis and anti-platelet therapy may need to be more aggressive after OPCAB surgery.