Platelet anesthesia with nitric oxide with or without eptifibatide during cardiopulmonary bypass in baboons

Objective: This study tested the hypothesis that nitric oxide or nitric oxi de and eptifibatide (Integrilin) reversibly inhibit platelet activation and consumption during cardiopulmonary bypass and rapidly restore platelet num bers and function after bypass. Methods: Nitric oxide, a short-acting, reve rsible platelet inhibitor, was studied with and without eptifibatide, a sho rt-acting, reversible glycoprotein IIb/IIIa inhibitor, in 21 baboons that u nderwent 60 minutes of normothermic cardiopulmonary bypass with peripheral cannulas, A control group, a group that received 80 ppm nitric oxide, and a group that received both nitric oxide and eptifibatide were studied, Blood samples were obtained at several time points to determine platelet count, aggregation in response to adenosine diphosphate, and levels of beta-thromb oglobulin, prothrombin fragment 1.2, and thrombin-antithrombin complex. Tem plate bleeding times were measured before and at 4 intervals after cardiopu lmonary bypass. Results: Both nitric oxide and the combination of the 2 dru gs significantly attenuated platelet consumption, improved postbypass funct ion, and seduced plasma beta-thromboglobulin release with respect to values in control animals, Both nitric oxide and the combination restored baselin e bleeding times 55 minutes after cardiopulmonary bypass ended. No signific ant differences between nitric oxide and the combination were found for any measurement. Conclusion: Nitric oxide with or without eptifibatide protect s platelets during cardiopulmonary bypass and accelerates restoration of no rmal bleeding times after operation in a baboon model. Although nitric oxid e and eptifibatide reversibly inhibit platelets by different mechanisms, in the absence of a wound no synergistic effect was demonstrated.