DEVELOPMENT OF AN IMPLANTABLE VENTRICULAR ASSIST SYSTEM

Background. This study describes the present state of progress in the development of the Jarvik 2000 ventricular assist system. Methods. Des igned for implantation in the human thorax, the system consists of a s mall (25 cm(3), 90 g) intraventricular axial-flow blood pump that tran smits power and data via internal electronics and a transcutaneous ene rgy transfer system. The pump is powered by portable internal and exte rnal polymer lithium ion batteries. The only moving part, the pump rot or, contains a permanent magnet of a brushless direct-current motor th at mounts an axial-how impeller and partial magnetic thrust support, w ith blood-immersed radial and thrust bearings. The motor uses a redund ant coil and electric lead design, which permits continued operation i n case of wire breakage. Results. Seven calves have been supported for an average of 107 days (range, 40 to 162 days) with prototypes of the Jarvik 2000 ventricular assist system. No physiologic complications h ave occurred. When its user is at rest, the pump produces flows of 5 t o 6 L/min with a decreased arterial pulse contour. Renal and hepatic f unctions have remained normal throughout the duration of all studies. Mean plasma free hemoglobin levels ranged from 4.3 to 11.4 mg/dL (mean , 6.3 mg/dL) for each study. Pathologic analyses of the heart and kidn eys revealed no damage related to the device. Conclusions. These studi es indicate that the Jarvik 2000 ventricular assist system is feasible in animals and holds promise for long-term support of patients. (C) 1 997 by The Society of Thoracic Surgeons.