The HeartSaver left ventricular assist device: An update

Background. Ventricular assist devices have been shown to be effective as b ridges to transplantation and recovery for patients with end-stage heart fa ilure. Current technology has been limited because of the need for percutan eous connections with controllers. The HeartSaver ventricular assist device (VAD) (World Heart Corporation, Ottawa, Ontario, Canada) was developed wit h the intention of having a completely implantable, portable VAD system. Th e system consists of an electrohydraulic blood pump, internal and external battery power, and a transcutaneous energy transfer and telemetry unit that allows for power transmission through the skin. Control of the device may be achieved locally or remotely through a variety of communication systems. Methods. The device has been modified with the Series II preclinical versio n being available for in vitro (mock loop) and in vivo (bovine model) testi ng. Results. Seventeen Series II devices have been functional on mock loops or other testing trials for an accumulated 900 days of operation. There have b een eight acute experiments using a bovine model to test various components as they have become available from manufacturing. Mean pump output was 10. 4 +/- 1.1 L/min in full-fill/full-eject mode. Changes in the last 24 months include (1) cannula redesign for better port alignment and integration of tissue valves; (2) battery redesign to convert to new lithium-ion cells; (3 ) optimized infrared information and electromagnetic inductance energy tran smission through various skin thicknesses and pigmentation; and (4) improve d reliability of internal and external controller hardware and software. Conclusions. Modifications have been required to optimize the HeartSaver VA D's performance. The final HeartSaver VAD design will be produced in the ne ar future to allow for formal in vitro and in vivo testing before clinical implantation. (C) 2001 by The Society of Thoracic Surgeons.