In Vitro Hemocompatibility of the BiVACOR Total Artificial Heart Near the Boundaries of Clinical Operation

Current mechanical circulatory support demonstrates excellent in vitro hemocompatibility when operated at the design point, although clinical requirements demand devices be used "off design," which may introduce higher stresses or residence times of blood. We evaluated the in vitro hemocompatibility of the BiVACOR total artificial heart (TAH) when operated at the boundaries of clinical need. Cattle blood was circulated in an in vitro blood loop at 3.0 L/min (low flow [LF]) or 12.0 L/min (high flow [HF]) in a pulsatile manner (+900 rev/min at 1 Hz) for 6 h using the TAH, for comparisons with a clinical comparator device operated in continuous flow. In LF, the normalized index of hemolysis (NIH) was 0.003 ± 0.002 g/100 L for the TAH, which was higher than the comparator (0.001 ± 0.001 g/100 L). In HF conditions, NIH was not different between devices: the TAH generated 0.004 ± 0.002 g/100 L and the comparator 0.002 ± 0.003 g/100 L. BiVACOR's TAH generated similar hemocompatibility to a clinically approved comparator, despite the TAH generating a clinically meaningful pulse pressure. Given that the TAH requires blood to transit the pump approximately twice as frequently as the comparator, these findings are promising for future applications.