EFFECT OF DEXTRAN ON PLASMA TISSUE-PLASMINOGEN ACTIVATOR (T-PA) AND PLASMINOGEN-ACTIVATOR INHIBITOR-1 (PAI-1) DURING SURGERY

Dextran is known to increase the plasminogen activation rate in vitro and to decrease the alpha(2)-antiplasmin activity. We decided to explo re the effect of dextran on plasma tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) during surgical trauma. Thirty-one patients undergoing elective surgery were given 500 ml of 6% dextran 70. Another nine patients serving as controls were given 50 0 ml of a glucose-electrolyte solution. The activities of t-PA and PAI -1 during surgery were determined, as was the concentration of t-PA an tigen. PAI-1 activity was decreased by 19% after infusion of 250 ml of dextran. After 500 ml, the activity was reduced by 22% (both P<0.05). The activity of t-PA was increased by 43% and 29% (both P<0.05) and t he antigenic amount of t-PA was increased by 18% and 15% (both P<0.05) after infusion of 250 ml and 500 ml of dextran, respectively. No chan ges in the variables were observed in the control patients. It is conc luded that infusion of dextran promotes fibrinolysis by enhancing plas minogen activation in patients subjected to trauma. Since elevated lev els of PAI-1 prior to surgery are known to predispose to deep vein thr ombosis, which may form already during the operation, the effect of de xtran on PAI-1 described here may explain its clot preventing properti es.