Postoperative changes in plasma tissue-type plasminogen activator and type I plasminogen activator inhibitor

To clarify the changes which occur postoperatively in intravascular fibrinolysis, plasma levels of tissue-type plasminogen activator (t-PA) antigen, the total plasminogen activator inhibitor type-1 (PAI-1) antigen, and the t-PA-PAI-1 complexes were assayed in this study. Blood samples were taken the morning before surgery, then at 0, 12, 24, 36, 60, 108, and 156h postoperatively in ten patients who underwent radical surgery for thoracic esophageal cancer. The plasma levels of the t-PA and total PAI-1 antigens, and the t-PA-PAI-1 complexes were then measured by enzyme immunoassay. The plasma t-PA and total PAI-1 levels increased significantly in the immediate postoperative period, the percent increase of the latter being much greater than that of the former. Moreover, the calculated free t-PA antigen level was decreased throughout the postoperative period, suggesting postoperative hypofibrinolysis. The platelet count and neutrophil elastase level were significantly correlated with the free t-PA antigen level atr = 0.630,P < 0.001, andr = -0.447,P < 0.01, respectively. The results of this study indicated that postoperative hypofibrinolysis caused by the increased synthesis of PAI-1 may enhance postoperative hypercoagulability, and this may lead to the development of organ damage. Thus, the concentration of the PAI-1 antigen may be a potentially important index for the prediction of postoperative illness.