Effects of prostacyclin infusion on platelet activation and postoperative blood loss in coronary bypass.

The effects of infusion of prostacyclin were studied in 41 patients undergoing aortocoronary bypass. Twenty-three patients received heparin (2 mg per kilogram of body weight) and prostacyclin (50 ng per kilogram per minute) during cardiopulmonary bypass (CPB). Eighteen patients received heparin (3 mg per kilogram). One hour after CPB, the platelet count was 98 +/- 16% of the value obtained before CPB in the prostacyclin group and 73 +/- 18% in the control group (p less than 0.001). The plasma level of platelet factor 4 rose only initially during CPB in the prostacyclin group, but increased continuously in the control group; at 90 minutes of CPB it was 92 +/- 35 ng per milliliter and 376 +/- 119 ng per milliliter, respectively (p less than 0.001). Beta-thromboglobulin showed a similar pattern. Postoperative chest drainage was 386 +/- 87 ml in the prostacyclin group and 596 +/- 342 ml in the control group (p less than 0.05). Blood transfused during and five days after operation was 1,359 +/- 751 ml in the prostacyclin group and 2,047 +/- 915 ml in the control group (p less than 0.05).