A prospective study of the clinical benefits of prostacyclin in 554 cardiopulmonary bypass procedures.

Abnormal bleeding after cardiopulmonary bypass (CPB) may result from incomplete neutralization of heparin, increased fibrinolytic activity, consumption of coagulation factors, or from a reduction in the number of circulating platelets together with impairment of platelet function. Although researchers have reason to believe that hemostasis after CPB could be improved with prostacyclin (PGI(2)), a potent inhibitor of platelet aggregation, the drug's clear-cut benefits in this respect have not yet been confirmed. After conducting an initial study concerning the fate of platelets during CPB, in which we determined that PGI(2) had a protective effect, we investigated the effects of PGI(2) infusion during CPB on postoperative blood loss in 554 open-heart surgery patients, 200 of whom underwent valve replacement, 200 of whom had coronary artery bypass grafting (CABG), and 154 of whom underwent repeat valve replacement or CABG. The patients were divided into 2 groups: 277 patients (the study group) received both heparin and PGI(2) during CPB, whereas the remaining 277 patients (the control group) were given heparin alone. Of the patients who underwent surgery for the first time, those treated with PGI(2) had a reduced mean blood loss (p < 0.05 only in CABG patients) in comparison with those who received heparin alone. Of the patients who underwent redo operations, those who received PGI(2) had a nonsignificant tendency toward reduced blood loss. The mean difference in blood loss between the study group and the control group had no clinical relevance, however, because it was less than the smallest practical unit of measurement (i.e., 1 unit of blood).