Implantable ventricular assist systems

A major goal of the Circulatory Support Program of the National Heart, Lung, and Blood Institute (NHLBI) is the development of a tether-free implantable ventricular assist system (VAS) to rehabilitate patients with advanced heart disease. In 1980, the NHLBI initiated a targeted program to develop and integrate implantable electromechanically powered VASs capable of operating for at least 2 years. The objectives of the program are to complete the development of the VAS and perform in vitro and in vivo evaluation studies. This article summarizes the research status of this NHLBI-sponsored program. It defines the VAS system requirements, describes the systems under development, identifies progress achieved to date, and identifies research challenges.