Intra- and postoperative fibrinolysis in patients undergoing cardiopulmonary bypass surgery.

The influence of cardiopulmonary bypass (CPB) on fibrinolytic activity was assessed in 100 patients with valvular heart disease or atrial septal defects. Euglobulin fibrinolytic activity (EFA), tissue type plasminogen activator (t-PA) activity, plasminogen activator inhibitor 1 (PAI-1) activity, plasminogen, alpha 2-antiplasmin (alpha 2-AP), fibrinogen degradation products (FDP), and D-dimer were measured pre-, intra-, and postoperatively. There were significant increases in EFA and t-PA activity (p less than 0.002), and decreases in plasminogen and alpha 2-AP (p less than 0.0001) intraoperatively with respect to baseline values. t-PA activity decreased significantly after surgery (p less than 0.002), whereas PAI-1 activity showed a marked increase shortly after operation and on postoperative day 1 (p less than 0.0001). FDP and D-dimer levels were significantly increased both intra- and postoperatively, the latter showing higher values (p less than 0.01 and p less than 0.0001, respectively). This study shows that there is an activation of the fibrinolytic system, as a result of the increased activation of plasminogen and decreased levels of plasmin inhibitors, during CPB surgery followed by a postoperative fibrinolytic shutdown.