Influence of major surgery on plasminogen activator activity in superficial hand veins

In 108 patients the plasminogen activator (PA) activity in superficial hand veins was measured with a fibrin slide technique before and after a major surgical operation. In the early postoperative period the PA activity was significantly decreased and the PA activity did not return to its preoperative value until the 14th postoperative day. The postoperative decrease was more than 0.5 arbitrary unit in 90 patients, resulting in an abnormally low value in 44. Overweight or an operation time of 180 min or more was found to increase the proportion of patients with a postoperative decrease in the PA activity. No sure relationship was demonstrable in the postoperative PA activity between patients with venous thrombosis and those without.