EFFECT OF APROTININ ON PLASMA FIBRONECTIN LEVELS DURING CARDIOPULMONARY BYPASS

Background. Acute depletion of plasma fibronectin levels has been repo rted during and after cardiopulmonary bypass; degradation of fibronect in by proteolytic enzymes has been suggested as one of the causes. Thi s study was designed to assess the possible preservation of fibronecti n levels by aprotinin during cardiopulmonary bypass. Methods. Plasma f ibronectin levels were evaluated in 19 patients undergoing either elec tive coronary artery bypass grafting or a valvular heart operation. Th e study was conducted prospectively in a controlled, randomized, doubl e-blinded manner. Nine test patients (group A) received intraoperative , intravenous administration of aprotinin; 10 control patients (group B) received equivalent volume of normal saline solution. Fibronectin l evels were measured immediately after induction of anesthesia (as the baseline for the study) and at the following times: after 5 minutes on bypass, after 30 minutes on bypass, immediately before the start of r ewarming, and after being off bypass for 5 minutes, but before protami ne administration. Results. Both groups' basic characteristics were ve ry similar. Group A patients were found to have significantly greater fibronectin levels than group B during and immediately after cardiopul monary bypass (p < 0.002). Conclusions. Administration of aprotinin in traoperatively appears to result in better presentation of fibronectin levels during cardiopulmonary bypass. Although the mechanism of actio n of aprotinin as a proteoIytic inhibitor remains unclear, it has been suggested that it exerts an inhibiting effect on proteolytic enzymes by forming an aprotinin-proteinase complex. The clinical implications of the greater level of fibronectin achieved by the intraoperative use of aprotinin during cardiopulmonary bypass need further evaluation. ( C) 1997 by The Society of Thoracic Surgeons