LONG-TERM ANIMAL SURVIVAL WITH AN IMPLANTABLE AXIAL-FLOW PUMP AS A LEFT-VENTRICULAR ASSIST DEVICE

We are developing an axial flow blood pump with Nimbus Inc. (AxiPump). For in vivo evaluation the AxiPump has been used as a left ventricula r assist device with a left ventricular and descending aorta cannulati on and implantation in a small pocket on the left lateral abdominal wa ll just posterior to the costal margin. Electrical and flow probe lead s exit the body transcutaneously. A purge line that delivers the purge fluid for lubrication of the seal between the rotor and stator bodies in the purge fluid bearing system is tunneled with the other leads. F ollowing acute animal studies, 3 animals have been supported for over 1 month with this AxiPump system. All laboratory results were within n ormal limits except during a recovery period from surgical damage. Hem olysis was not a serious problem. In the first case, the purge system failed at 28 days, and in the second and third cases, the nonpurge bea ring system worked well for 57 and 52 days, respectively. Bearings are still under development in this kind of pump. However, this success e ncourages us to improve the AxiPump as a long-term assist device.