THE HEARTMATE II AXIAL FLOW LVAS

Abstract

The HeartMate II (HMII) LVAS is an outgrowth of the NIH IVAS Contract that Nimbus and the University of Pittsburgh (UOP) have been working on the last several years. In 1997 Nimbus became part of Thermo Cardiosystems Inc. (TCI) and since then progress has been enhanced significantly on all phases of development. Efforts are now under way to complete qualification testing of the HMII for demonstration of readiness for human use. Key development issues have been: (1) continued refinement of the inflow/outflow cannulae, (2) completion of a wearable system driver and, (3) testing of a closed loop speed control system. The HMII uses TCI's FDA approved HeartMate VE support equipment consisting of batteries, power base unit, and clinical monitor. Packaging and sterilization validations for the pump and system driver have been completed. Cadaver fit studies at UOP have been conducted to verify implant site and fit, and over 20 in vivo experiments have been run to demonstrate biocompatability and auto speed control functionality. The first clinical application will be of a percutaneous system with only the pump implanted. A fully sealed system is also being developed using a new and refined transcutaneous energy transmission system. An implanted battery is under development using Lithium Ion cells from Wilson Greatbatch Ltd. Completing the sealed system is an implanted electronic driver, which uses radio telemetry to transmit diagnostic information across the skin.