PRESSURE SENSOR CONTROL OF VENTRICULAR ASSIST DEVICES

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Congestive heart failure (CHF) is responsible for over one half million hospitalizations per year in the U.S. and the prognosis for such patients has been bleak. Cardiac transplantation has been seen as the only positive therapy for end stage CHF, and the ventricular assist device (VAD) has been viewed only as a bridging method until transplantation. However, recent studies have demonstrated that with adequate long-term reduction of the ventricular work load, about one third of these patients can be improved sufficiently to permit weaning from mechanical support. Responding to such encouraging findings, miniature VAD and total artificial heart (TAH) developments have been or are being designed as long term alternatives to heart transplants. An example of such a development is the DeBakey VAD. The device is a miniature, totally implantable VAD designed to meet normal cardiac output requirements at a low energy consumption rate. However, the development of a suitable VAD controller has become a serious problem. Lack of an adequate VAD controller is now the major obstacle in the way of clinical application for such devices. Knowledge of inlet and outlet pressures is critical for the control of such VADs. Unfortunately, while the intrinsic characteristics of state- of-the art pressure sensor chips meet VAD controller requirements, these requirements have not yet been met long term in a blood environment. Obstacles to overcome are 1) adequate insulation of the device from hostile environments, and 2) providing a level of biocompatibility which assures both patient protection and reliable device operation. The goal of this Phase I study is to establish feasibility for the development and preparation of sensor surface treatments, using modern plasma assisted- chemical vapor deposition (PA-CVD) technology, which will provide the needed levels of biocompatibility and device insulation. PROPOSED COMMERCIAL APPLICATIONS: Estimates of the annual need for total artificial hearts and ventricular assist devices range from a low of 17,000 patients to a high of 240,000 patients annually in the U.S. alone. In 1991, only 2,075 of these patients could be provided with a long-term solution through cardiac transplantation. With such a high need for total artificial hearts and ventricular assist devices in the U.S., there is significant market opportunity. It is anticipated that continuous flow devices will have a larger market share than pulsatile devices because of their simplicity, higher reliability, and lower cost.