Doctors and Engineers Aim to Build a Device to Prevent the Need for a Transplant
Houston, TX (May 13) –A team of physician-scientists and engineers at the Texas Heart Institute (THI) are conducting important research on a promising new and innovative left ventricular assist device (LVAD) designed for use in patients with early-stage heart failure.
Several members of THI’s Center for Preclinical Surgical and Interventional Research will serve as co-investigators on the project, including Alex Smith, PhD, Yaxin Wang, PhD, and the center’s Co-Director, Luiz C. Sampaio, MD, with Drs. O. H. Frazier and William Cohn serving as principal investigators.
If the novel LVAD works as expected, heart failure patients may never need a heart transplant or require the implantation of a mechanical circulatory support device such as a traditional LVAD or a total artificial heart.
The proposed LVAD being studied is a small pump that can be attached to the wall of the heart between its two upper chambers (the atria). The new device can be implanted by a minimally invasive procedure. The pump takes over some of the heart’s pumping function, thereby reducing the workload of the heart’s left ventricle, which beats 100,000 times a day on average as it performs its critical function of pushing blood to rest of the body.
Much like using a crutch can prevent a bad knee from getting worse, this novel approach to assisting the heart in its pumping action could not only slow the progression of heart failure but actually restore some of the lost function of the patient’s diseased heart.
Current LVADs must be implanted by open-heart surgery that involves making a hole in the left ventricle of the heart in very sick patients. In contrast, the miniature pump under development could be implanted without opening the chest or cutting into the left ventricle and could therefore be used in less sick patients. The team believes that keeping the left ventricle intact will preserve its function, offering the best possible environment for myocardial reconditioning (the recovery of damaged heart muscle), which could result in remission from heart failure.
The interest in myocardial reconditioning arose from another research discovery made at THI a few years ago, when Dr. Frazier and team identified an opportunity to more aggressively pursue ventricular reconditioning to delay or avoid the need for heart transplantation. They reported their findings in the Journal of Heart and Lung Transplantation.
Dr. Frazier and colleagues concluded that the potential for the native heart to recover function after long-term continuous-flow LVAD support should be further explored, and that a therapeutic goal of heart assist devices could in fact be to simply recondition the heart muscle. Thus, a patient might have an LVAD implanted and, after a period of time, have the LVAD explanted and return to medical management. Dr. Frazier and his team further concluded that this strategy might be especially useful in younger patients with dilated cardiomyopathy.
Mechanical circulatory support (MCS) devices for heart failure treatment are typically used either as a bridge to heart transplant therapy or for permanent support. Today, MCS is limited to patients with end-stage heart failure. However, earlier MCS implantation is associated with better clinical outcomes because the patients don’t yet have the multi-organ dysfunction (especially kidney dysfunction) that often accompanies end-stage heart failure.
The development of the new LVAD will require careful design of hydraulic, motor, and bearing systems, all of which must avoid damaging the cells or proteins in the blood. This type of research requires a multidisciplinary approach, and the new funding allows the team of engineers, surgeons, and other researchers to specifically refine the miniature magnetic levitation motor system for the new pump, as well as the hemocompatibility of the hydraulic and motor components.
This project involves a global collaboration and will benefit from the expertise of Nobu Kurita, PhD (Ganma University, Japan), who is contributing his experience in magnetic levitation (maglev) design, and Chris Chan, PhD (Griffith University, Australia), who will evaluate the design prototypes to make sure they are not damaging blood cells.
Once the pump design has been refined to better avoid blood trauma, it will be tested in vitro in a continuous-flow (mock) blood loop simulator. “We believe the pump will improve myocardial reconditioning, advance the technology used in the MCS field, decrease the need for highly invasive MCS device implantation, and reduce the need for heart transplantation,” said Dr. Frazier.
Research reported in this publication is supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health under Award Number R56HL143489. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
About Texas Heart Institute
The Texas Heart Institute (THI), founded by world-renowned cardiovascular surgeon Dr. Denton A. Cooley in 1962, is a nonprofit organization dedicated to reducing the devastating toll of cardiovascular disease through innovative and progressive programs in research, education and improved patient care. More information about THI (@Texas_Heart) is available at www.texasheart.org.
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