A CANINE EX-VIVO SHUNT FOR ISOTOPIC HEMOCOMPATIBILITY EVALUATION OF ANHLBI 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 u sing radioisotopic tracers made it possible to dynamically monitor the deposition of labelled blood cells and proteins on a NHLBI.DTB primar y reference material polydimethylsiloxane (PRM.PDMS) and on a IUPAC re ference material polyvinyl chloride (IUPAC.PVC). On the one hand, leuk ocyte affinity tau(s)(leu) (number of deposited leukocytes mm-2 s-1) w as 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 deposit ed platelets mm-2 s-1) was significantly different (p < 0.05) for IUPA C.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 quanti fy the adsorption of different radiotracers, but also to evaluate the superficial distribution of the labelled biological species on the inn er surface of the tested biomaterials.