Proceedings

Preservation of Platelets during Cardiopulmonary Bypass with ZK36374: A New Prostacyclin Analogue

Hospital of the University of Pennsylvania and PSICOR, Inc., Philadelphia, PA

^* Direct communications to: Jeffrey C. Crowley, PSICOR, Inc., 810 East Grand River, Brighton, MI 48116

Abstract

Extracorporeal circulation is associated with extensive alterations in platelet number and function. In certain individuals these adverse platelet changes are exacerbated by heparin. ZK36374 (ZK), a stable analogue of prostacyclin, reversibly inhibits all phases of platelet activation. A patient was presented with heparin induced platelet activation and paradoxical thrombosis who required cardiopulmonary bypass to correct severe tricuspid stenosis and ASD. We employed full heparinization and ZK to prevent surface and heparin induced thrombocytopenia. Prior to heparinization, a constant infusion of ZK was begun at 10 nanograms/kilogram/minute, tapered to 2 nanograms/kilogram/minute during bypass, and maintained until heparin was reversed with protamine. Prior to bypass, platelets demonstrated 50% reactivity and 2% reactivity when challenged by ADP and epinephrine, respectively, indicating inhibition of platelet function by ZK. Two hours after arrival in recovery 92% prebypass circulating platelet count, 90% preservation of platelet reactivity to ADP, and a template bleeding time near control were achieved. ZK was used safely to prevent both heparin and surface induced platelet changes during cardiopulmonary bypass in this patient.