Chronic in vivo function of a new ventricular assist device: the extracorporeal pulsatile assist device (EPAD)

An extracorporeal pulsatile assist device (EPAD) is a valveless, single-chambered, pneumatically-actuated blood pump composed of a graft conduit, connecting ring, bladder, and blowmolded housing. This allows a simple and quick surgical procedure and is easily actuated with a conventional intraaortic balloon pumping console if desired. To evaluate in vivo pump functions, the EPAD was tested in calves as a left ventricular assist device for 6-24 days. The EPAD was well synchronized to the natural heart beat up to 130 bpm in the counterpulsation mode with mild systemic heparinization (active clotting time: 200-250 seconds). Heart rate, coronary flow and cardiac output were not significantly changed by on-off testing. However, the pump showed promising diastolic augmentation (10.8% increase in the diastolic pressure time index) in these chronic animal experiments.