New Developments In Interactions Of Blood With Artificial Surfaces

Abstract

There are major new developments concerning interactions of blood with artificial surfaces. There is new understanding of mechanisms: the nature of the plasma protein film adsorbed on artificial surfaces, the interaction of HMW kininogen with adsorbed fibrinogen, the significance of adsorbed antithrombin to the behavior of heparinized surfaces, and the lack of prostacyclin production and ADPase activity. There are new in vivo diagnostic methods: measurement of labelled platelet and fibrinogen survival, assay of plasma levels of products of activated coagulation or platelets (FPA, thrombin/antithrombin complexes, β - thromboglobulin, platelet factor 4 thromboxane B2), and in vivo detection of thrombi with 125I-fibrinogen or 1 Inplatelets. New methods also exist for characterization of surfaces: ESCA, SEM, TIRIS, TIRFS. New materials are available with different modes of thromboresistance: bland polymers such as polyurethanes and siloxanes, modified collagens, heparinized surfaces, porous materials, and aldehyde treated materials of animal origin. There are new drugs for protection of hemostatic elements during extracorporeal circulation: PGI2, PGE1, ibuprofen. New applications for prosthetic devices have become practical: peritoneo-jugular shunts for treatment of ascites, left ventricular assist devices, intra-aortic balloon pumps, total artificial hearts.Such developments raise important new questions: the relation of short-term tests of thromboresistance to longterm behavior of devices in vivo, the problem of thrombi at the junction of prosthetic device with the host, calcification in long-term applications, and new approaches to management of traditional clinical problems (e.g., continuous treatment with portable miniaturized hemodialysers, small vessel prostheses, extracorporeal cardiopulmonary support without anticoagulation).Subsequent speakers will consider these topics more fully.