FIBRINOLYSIS DURING MAJOR ABDOMINAL-SURGERY

To investigate intraoperative changes in tissue plasminogen activator (t-PA) activity and antigen, its fast acting inhibitor and other components of the fibrinolytic system, blood was taken on 7 occasions from 12 patients during major abdominal surgery. In 7 patients t-PA activity rose from a median of 217 miu/ml preoperatively to a peak of 1500 miu/ml at bowel clamping, falling below preoperative value by the first postoperative day (p<0.02). t-PA antigen levels reacted similarly, except that the postoperative values of 12.6 ng/ml were higher than the preoperative value of 5.7 ng/ml (p<0.05). t-PA inhibitory activity and PA inhibitor 1 (PAI-1) antigen rose from 5.7 miu/ml and 9.5 ng/ml respectively preoperatively to 46 miu/ml and 39.5 ng/ml on the first postoperative day (p<0.001). In contrast, in the remaining 5 patients t-PA activity remained at the lower limit of detection throughout. Preoperative levels of t-PA antigen were comparable to those in the first group of patients, but did not increase during the operation. Concentrations of t-PA inhibition and PAI-1 antigen were consistently high in these 5 patients and did not rise postoperatively. There were no changes in alpha-2-antiplasmin, protein C antigen, urokinase, or intrinsic plasminogen activator, and no differences between the 2 groups. Plasma vasopressin concentrations increased in both groups. All 12 patients had similar increases in fibrinopeptide A and crosslinked FDP. The results indicate that the fibrinolytic response to major surgery is variable. These findings may be relevant to the genesis of postoperative venous thrombosis. © 1990 Longman Group UK Ltd.