INTEGRILIN PREVENTS PROLONGED BLEEDING TIMES AFTER CARDIOPULMONARY BYPASS

Background. Cardiopulmonary bypass reduces platelet number and functio n, increases postoperative bleeding time, and is the major, unsolved c ause of nonsurgical bleeding after open heart operations. Temporary in hibition of platelet function during cardiopulmonary bypass (platelet anesthesia) protects platelets and reduces postoperative bleeding time and bleeding. Methods. Integrilin, a short-acting, reversible platele t glycoprotein IIb/IIIa inhibitor was studied in 28 baboons that had 6 0 minutes of normothermic cardiopulmonary bypass using peripheral cann ulas. A control group, two groups that received different doses of Int egrilin, and a group that received a combination of Integrilin and low -dose Iloprost were studied. Blood samples for platelet count, aggrega tion to adenosine diphosphate, beta-thromboglobulin, prothrombin fragm ent F1.2, thrombin-antithrombin complex, and fibrinopeptide A were obt ained at seven time points. Template bleeding times were measured befo re and at five intervals after cardiopulmonary bypass. Results. Both d oses of Integrilin and the combination of Integrilin and Iloprost sign ificantly protected platelet number, inhibited the response to adenosi ne diphosphate, and reduced postoperative bleeding times, but they did not reduce beta-thromboglobulin release except in the high-dose Integ rilin group. Thrombin formation and activity were qualitatively, but n ot significantly, reduced in all treatment groups. Bleeding times were not significantly different from baseline at the time protamine was g iven in the combination group and 60 minutes after protamine administr ation in all treatment groups. Conclusions. Integrilin alone or in com bination with Iloprost significantly reduces platelet activation durin g cardiopulmonary bypass and produces normal or near-normal bleeding t imes at the time protamine is given.