BLOOD INTERACTION WITH A BIOLINE HEPARIN-COATED HIA-VAD - A STUDY ON CALVES

The blood compatibility of ventricular assist devices developed by the Helmholtz institute Aachen (HA-VAD's) was tested on calves. Seven cal ves received a non-coated HIA-VAD (control) and three a Bioline hepari n coated device. The circulatory support of these HIA-VAD's lasted one week. Mechanical blood cell trauma estimated by hematocrit (Hot), hem oglobin (total Nb) and free plasma hemoglobin (free Hb) levels did not differ in either group. All HIA-VAD's in the control group remained t hrombus free, except on one occasion when an inflow cannula was obstru cted by a thrombus located in the tip. After circulatory support, the animals in this group seemed clinically healthy However, thrombus form ation was observed in the three heparin coated HIA-VAD's. One animal i n this group died from complications after re-operation for pneumothor ax on the fifth day of support, whereas the other two animals seemed c linically healthy in these three animals, a stronge decrease in platel et numbers was measured even after 24 hours of support which recovered after 72 hours. This decrease in platelet numbers was associated with a lower degree of platelet aggregation ability stimulated by ADP (p<0 .05). Fibrin(ogen) degradation products (FDP) increased significantly immediately after the implantation procedure (p<0.05). Fibrinogen leve ls initially decreased during the implantation procedure, but increase d thereafter in both groups. The FDP levels remained high in this grou p, although the FDP levels in both groups were decreased after the imp lantation procedure. The ex vivo measured circulating heparin levels w ere lower in the heparin coated HIV-VAD group despite the equally admi nistrated heparin doses in both animal groups. No differences were mea sured in either group with regard to white blood cell (WBC) numbers an d complement hemolytic activity (CH50). Despite these hemostatic chang es, no mechanical trauma could be demonstrated after seven days of cir culatory support.