LONG-TERM FOLLOW-UP OF CALVES IMPLANTED WITH THE IN-COR I VENTRICULAR ASSIST DEVICE

Abstract

The INCOR I ventricular assist device is an axial-flow pump with magnetically levitated hearings and low power consumption. It is capable of pumping 5 liters against 100 mmHg at a rotational speed of 8,600 rpm. The VAD was evaluated in 14 calves to test hemolysis and thrombogenicity in short-and long-term observation. Five died within 12 hours postop. due to persistent ductus Botalli which was not anticipated and therefore overlooked. One died due to slip-off of a cannula which was inadequately connected. Six were euthanized after 40 days (d) due to the requirements of the European approval authorities. One was euthanized after 150 d, one is still on device (> 170 d). Clinically, no signs of thromhoemhbolic events were observed. Mean flow and power consumption were constant over the observation period. PFH was slightly elevated for I week postop., as was LDH. Both parameters normalized thereafter and remained constant. Plasma split products did not show any increase, as were creatinine and urea. At explantation we found no thrombus deposits inside the cannulas or the pump. However, at the inflow site of one pump some fibrin deposits were seen which were related to poor polishing of the surface. Additionally, in one calf's kidneys signs of a thromboembolic event could be seen. No further biological abnormalities at all were detected during the trial. With regard to the pump, no malfunction of the pump was observed. The overall test results of INCOR I are encouraging. They have to be confirmed in a clinical trial to start in February 2002.