THE SCIENTIFIC BASIS FOR SELECTION OF MEASURES OF THROMBOGENICITY

The interaction of blood with materials is central in the thrombogenic response obtained in extracorporeal circulation. A number of processe s are involved in determining whether there is generation of thrombin and the formation of an obstructive thrombus: these include activation of blood coagulation, platelet activation, trauma to the blood, blood flow, and use of anticoagulants (e.g. heparin). The way in which thes e processes produce their thrombogenic responses and interact is descr ibed to provide a basis for the understanding of the methodological ap proaches currently used to investigate thrombogenicity. It is conclude d that much available methodology has limitations and no one indicator of the thrombogenic activity of a material or system (such as extraco rporeal circulation) can be wholeheartedly recommended for all applica tions. Nevertheless, depending upon the circumstances of the particula r investigation the assays to coagulation activation markers, thrombin -antithrombin III complex, prothrombin fragment F1+2 and fibrinopeptid e A are emerging as valuable aids in the assessment of thrombogenicity . The information gained by use of these assays will require additiona l and complementary information from other assays of perhaps platelet function/activation, level of anticoagulant, and other coagulation mar kers.