Effects of prostacyclin infusion on platelets and hemodynamics in coronary bypass surgery

Twenty patients undergoing aorto-coronary bypass were randomly assigned to a prostacyclin treatment group or control group. Eight patients received 2 mg/kg heparin and 10 ng/kg/min prostacyclin before cardiopulmonary bypass (CPB) and 50 ng/kg/min during CPB. Twelve patients, serving as controls, received 3 mg/kg heparin. Heparinization resulted in a slight but significant increase of plasma beta-thromboglobulin in the control group but not in the prostacyclin group, and of plasma platelet factor 4 (PF-4) in both groups. After 90 minutes of CPB, beta-thromboglobulin was 408 (SD 128) ng/ml in the control group and 111 (SD 50) ng/ml (p less than 0.001) in the prostacyclin group. Platelet count, corrected for hemodilution, was 92% (SD 10) of the pre-CPB value after 10 minutes of CPB and 89% (SD 7) one hour after CPB in the control group, as compared to 113% (SD 10) and 145% (SD 18), respectively, in the prostacyclin group. Prostacyclin infusion before CPB reduced systemic vascular resistance to half of that of the control group, lowered mean arterial blood pressure, and increased cardiac index by 60% to 80%. An infusion of prostacyclin before CPB does not add to the already excellent platelet protective effect of 50 ng/kg/min prostacyclin during CPB, but may be used for vasodilation.