For some patients with end-stage heart failure, left ventricular assist devices (LVADS) provide a life-saving option. These artificial heart pumps take over the function of the left ventricle in the heart, so that they can be sustained until a donor heart becomes available for transplantation – or perhaps indefinitely. Risks associated with LVADS are significant, however (infection, bleeding, and stroke), as is the burden that comes with having to wear an external battery pack at all times.
Those burdens could soon substantially fade, if a newly designed pump proves durable in clinical trials. Researchers at the University of Pittsburgh and University of Washington have developed a wireless pump called the Free-Range Resonant Electrical Energy Delivery System, or FREE-D, that contains no driveline through the skin like current models do. Their wireless alternative is powered by induction rather than batteries, so that recipients can wear a small transmitter in a vest or other external garment, which communicates with the receiver that is implanted in the heart. Without a driveline connecting an external battery to the heart, patients’ risk of infection would drop dramatically, as would the other problems associated with current LVADS.
* Photo Credit: Pramod Bonde, MD, University of Pittsburgh, Department of Medicine
In a separate development, researchers at Texas Heart Institute developed a very different type of LVAD, one called the ‘pulseless heart’ because of its continuous flow process rather than pulsing mechanism. This device was created by joining two turbine-like rotary pumps, which together act as a substitute for both sides of the heart. Patient Craig Lewis lived for a month with the continuous flow pump in his chest before dying of other complications of amyloidosis; the heart pump showed no problems whatsoever. Unlike FREE-D, however, the pulseless pump is not wireless – it still requires a driveline connecting it to an external battery. But the success of the continuous flow pump, in sustaining both Mr. Lewis as well as animals that continue to thrive with the pump today, is important because it has demonstrated that despite what all of us may have thought till now, a pulse is not essential to life.
According to Yoshifumi Naka, MD, PhD, Director, Cardiac Transplantation and Mechanical Circulatory Support Programs, the development of a wireless LVAD is extremely significant. “This would greatly improve the quality of life for LVAD recipients,”says Dr. Naka. “At this time, currently available LVADS are the best option for patients with end-stage heart failure. As device technology is continually improved, current complications will be overcome. In the future, it may be possible to transition to totally implantable devices with no driveline.”
FREE-D will not be available for at least several years, as the developers must still overcome remaining technical challenges and the device must undergo rigorous clinical testing before approval.
The heart transplant program at NewYork-Presbyterian/Columbia is the top cardiac transplant program in the United States by volume. In an effort to overcome some of the limitations of transplantation (in particular, the long waiting lists for donor organs), our surgeons have established the Mechanical Circulatory Support Program to develop and implement cardiac assist devices.