A CANINE EX-VIVO SHUNT FOR ISOTOPIC HEMOCOMPATIBILITY EVALUATION OF A NHLBI DTB PRIMARY REFERENCE MATERIAL AND OF A IUPAC REFERENCE MATERIAL

Factors determining the thrombogenic response to particular artificial surfaces were investigated ex vivo in a canine shunt model. Methods using radioisotopic tracers made it possible to dynamically monitor the deposition of labelled blood cells and proteins on a NHLBI.DTB primary reference material polydimethylsiloxane (PRM.PDMS) and on a IUPAC reference material polyvinyl chloride (IUPAC.PVC). On the one hand, leukocyte affinity tau(s)(leu) (number of deposited leukocytes mm-2 s-1) was not significantly different between IUPAC.PVC (tau(s)(leu) = 1.2-2.5) and PRM.PDMS (tau(s)(leu) = 1.5-3.4) and the fibrinogen adsorption rate varied from 33 to 48.10(-5) mug mm-2 s-1 for both these materials. On the other hand, platelet affinity tau(s)(plat) (number of deposited platelets mm-2 s-1) was significantly different (p < 0.05) for IUPAC.PVC and PRM.PDMS (tau(s)(plat)PVC = 683 +/- 200 > tau(s)(plat)PDMS = 327 +/- 80). Scanning electron micrographs of adherent platelets, red cells and leukocytes after blood contact ex vivo were performed after each experiment. This preliminary work contributes not only to quantify the adsorption of different radiotracers, but also to evaluate the superficial distribution of the labelled biological species on the inner surface of the tested biomaterials.