Effects of extracorporeal circulation and heparin on the phenotype of platelet surface antigens following heart surgery

In this prospective study, the time-dependent effects of extracorporeal cir culation and heparin-mediated effects on platelet surface antigens in vitro were investigated using whole blood flow cytometry. Blood samples were dra wn prior to and following extracorporeal circulation in 89 patients. The re sponse of surface antigen expression (glycoprotein IIb/IIIa, P-selectin, an d glycoprotein Ib) with and without in vitro stimulation was measured. A si gnificant correlation of the duration of extracorporeal circulation with th e postoperative response of glycoprotein IIb/IIIa, glycoprotein Ib, and P-s electin to in vitro activation was found. Postoperative P-selectin and glyc oprotein Ib expression stimulated with ADP correlated to blood loss; Hepari n in vitro significantly reduced glycoprotein Ib expression. Heparin, as we ll as the duration of extracorporeal circulation, independently correlated to phenotypic changes of platelets following extracorporeal circulation. Th e significant correlation of these variables to postoperative blood loss de monstrates their relevance to platelet function in vivo. (C) 2000 Elsevier Science Ltd. All rights reserved.