Beneficial effect of both tranexamic acid and aprotinin on blood loss reduction in reoperative valve replacement surgery.

BACKGROUND: Blood loss after cardiac surgery is a continuing concern of caregivers and patients. The acute inflammatory reaction initiated by the extracorporeal circuitry, necessary to perform the procedure, stimulates the coagulation cascade, and the resultant hyperfibrinolysis is considered to be a major contributing factor of blood loss. The necessity to reduce transfused blood products after cardiac surgery is important, as it reduces the potential transmission of serious viral infections, improves operative outcomes, and provides containment of costs. The purpose of this study was to compare the effect of synthetic antifibrinolytic tranexamic acid with naturally occurring antifibrinolytic aprotinin on blood loss and to study requirements for transfusion of blood products after repeat cardiac valve surgery.

METHODS AND RESULTS: Two randomized trials had been previously conducted, each comparing the respective treatment groups, aprotonin (AP group) and transexamic acid (TA group), with a control group [placebo (P)] in double-blind fashion with the same inclusion and exclusion criteria. The number of patients in the four designated groups are as follows: TA, 22; TA-P, 19; AP, 24; and AP-P, 36. The dosage of aprotinin (high-dose) encompassed a 280-mg loading dose infused after induction of anesthesia, 280 mg in the CPB prime solution, and 70 mg/h for a period of 6 hours. The tranexamic acid dose was 10 mg infused in 500 mL of normal saline. The blood loss was measured intraoperatively and postoperatively. The transfusion of homologous blood products was conducted in a standardized fashion. Both the TA and AP groups lost less blood intraoperatively, in total, less than either of the placebo groups, and less blood postoperatively than the TA-P group (P<.05). The postoperative blood loss (median) was 538 mL for the TA group, 455 mL for the AP group, and for the respective placebo groups, 1170 mL and 595 mL. The total blood loss was 1340 mL for the TA group, 1383 mL for the AP group, and 3250 mL and 2450 mL, respectively for the placebo groups. The total blood product use revealed no differences between the two placebo groups (P=NS) nor between the two treatment groups (P=NS).

CONCLUSIONS: Tranexamic acid and aprotinin are both effective in reducing intraoperative and postoperative blood loss and the need for blood product transfusion for patients undergoing reoperative cardiac valvular surgery.