ABSTRACT
BACKGROUND: We are developing and testing a new ventricular assist device (VAD) to be powered by conditioned skeletal muscle. METHODS: To evaluate the VAD hardware and to develop a muscle training regimen, 8 calves have been used in studies in which the right latissimus dorsi muscle was employed. The experiments were carried out to an approximately 4-month duration. RESULTS: There was significant conversion of type II (fast twitch) to type I (slow twitch) muscle fibers. This did not correlate well, however, with device performance. The device stroke volumes ranged from approximately 17 to 90 cc. This variability of outcome occurred despite the fact that identical hardware, surgical procedures, and training regimens were employed. CONCLUSIONS: The results from the first eight studies lead us to speculate that perfusion may be important even when the muscle is working at pressures much lower than systemic blood pressure levels. In an attempt to augment tissue perfusion, we plan to investigate thermally induced angiogenesis as a possible mechanism for increasing blood flow to the tissue.
Subject(s)
Heart-Assist Devices , Muscle Contraction/physiology , Muscle, Skeletal/physiopathology , Animals , Cattle , Electric Stimulation , Equipment Design , Humans , Muscle, Skeletal/pathology , Stroke VolumeABSTRACT
A portable, percutaneous, battery-operated left ventricular assist device intended for intermediate and long-term use is described. The system performed satisfactorily in vitro for periods of up to 9 months and in vivo for periods in excess of 3 months. Long-standing hypertension was observed in a 98 day implant with accompanying renal and visceral vascular changes. No evidence of peripheral thromboembolism was seen. Examination of the textured blood pump surface revealed an established biologic lining, characteristic of that previously seen in calves with some evidence of peripheral calcification.
