[Left ventricular assist system]

Two types of artificial heart, the total artificial heart (TAH) and ventricular assist system (VAS), have been utilized in patients with end-stage heart failure waiting for heart transplantation (bridge to transplantation). The TAH is a system to replace the native heart, whereas the VAS is a system to support the left ventricle (LVAS), right ventricle (RVAS), or both ventricles (BVAS) while maintaining native cardiac function. There are two types of VAS, paracorporeal VAS and implantable VAS. Implantable VAS devices such as Novacor LVAS and HeartMate LVAS are only available for LVAS, although paracorporeal VAS, such as Toyobo VAS, Zeon VAS, and Thoratec VAS, are available for RVAS, LVAS, or BVAS. Due to recent advances in the VAS, the "patient discharge program" from hospital has been promoted for improvement of the quality of life (QOL) and reduction of medical costs. VAS also have been utilized as "bridges to recovery" for native hearts or for "semipermanent use" in patients without indications for heart transplantation, and superior clinical results of VAS therapy compared with conservative therapy have been reported in terms of one-year survival rate and improvement of QOL. Recently, several inexpensive VAS systems with an axial or centrifugal pump have been developed and the initial clinical trials of these systems have recently started in Western countries. Another remarkable technological advance in VAS is the Lion Heart (Arrow) which is a totally implantable VAS system the includes an energy transmission system. We expect that recent technological progress in VAS will improve the survival and QOL in patients with end-stage heart failure.