The hemostatic mechanism after open-heart surgery. I. Studies on plasma coagulation factors and fibrinolysis in 512 patients after extracorporeal circulation.

Blood coagulation screening profiles were performed in 512 patients who underwent open-heart surgery with extracorporeal circulation. Severe coagulation disorders were found in 29 (5.6 per cent) patients. The most common abnormalities were low one-stage prothrombin time (PT) activities and impaired whole blood clot retractions. In the majority of patients the discrepancy between low PT's and normal or only slightly depressed factor II, V, VII, and X activities was explained by the presence of an inhibitor of the extrinsic system. Eight patients demonstrated the heparin rebound phenomenon but only 1 bled excessively. The pattern of severe hepatic dysfunction was found in 4 and severe depression of vitamin K-dependent factors due to oral anticoagulants in 2. Two had disseminated intravascular coagulation. Seventeen patients with normal coagulation screening profiles bled excessively postoperatively. Of these, 2 had moderate thrombocytopenia associated with a marked platelet functional abnormality. Revision of the wound in 13 revealed a surgical hemostatic defect and in 2 the cause of bleeding could not be determined.