Alteration in fibrinolytic capacity after operation.

The fibrinolytic response to 20 min of forearm venous occlusion was studied in patients undergoing major and minor operations. Fibrinolytic capacity, which is defined as the increase in fibrinolytic activity resulting from a period of venous occlusion, was significantly reduced on the first postoperative day after major operations, but not after minor operations. Since venous occlusion results in the release of plasminogen activator from the vascular endothelium into the blood, these findings suggest that the reduction in the level of spontaneous fibrinolytic activity after major operations is the result either of exhaustion of the vascular endothelium of plasminogen activator or defective synthesis and release of this enzyme from the endothelium.