Changes in factor VIII proteins after cardiopulmonary bypass in man suggest endothelial damage

16 patients undergoing coronary artery bypass grafting using cardiopulmonary bypass (CPB) had blood samples taken at various times before, during and up to 1 week after surgery for estimation of beta-thromboglobulin (BTG), alpha-1-antichymotrypsin (ACT), factor VIII procoagulant protein (VIII:C), von Willebrand factor antigen (vWF:Ag) and ristocetin co-factor (vWF:RiCoF). vWF:Ag and vWF:RiCoF rose during and following surgery in a different manner to ACT. At 1 week there was a significantly disproportionate rise in vWF:Ag compared to vWF:RiCoF which suggested a degree of pulmonary endothelial damage. Prostacyclin, which was administered to 8 of the patients during CPB, reduced platelet activation as measured by a reduction in the release of BTG and also attenuated the consumption of VIII:C. It had no effect on pulmonary endothelial damage as measured by the ratio of vWF:Ag to vWF:RiCoF.