Egemen Tuzun, M.D., scientific director of the Texas A&M Institute for Preclinical Studies, will present a seminar Monday (Sept. 6) at 4:10 p.m. in Room 106 of the Jack E. Brown Engineering Building on campus.
Tuzun’s talk, “The effect of continuous flow left ventricular assist devices on coronary perfusion and aortic valve opening: Dark side of the moon!,” is part of the Department of Biomedical Engineering’s seminar series.
Abstract
Heart failure remains the leading cause of premature death in the United States and Europe, despite significant recent advances in the diagnosis and management of coronary and valvular heart diseases. Heart transplantation is a well?established therapy for end?stage heart failure, but limited donor organ availability and limited long?term survival have restricted its epidemiological impact.
For patients who are not candidates for heart transplantation, there are many cardiac assist devices under development that address the needs of patients with isolated left ventricular failure. First generation mechanical ventricular assist devices (VADs) using pulsatile?flow properties have proven successful as rescue and chronic support devices for patients requiring mechanical cardiac support. However, the size of the pulsatile VADs has limited their usefulness in all but the largest patients, and their complex design allows numerous possibilities for failure, resulting in a high rate of postoperative complications such as infection, thrombosis or device failure.
The development of smaller, simpler, and more efficient second generation, continuous?flow pumps may provide a solution to the problems associated with pulsatile VADs. It has been recently demonstrated that continuous?flow pumps working as left ventricular assist devices (LVADs) can provide adequate systemic flow to a heart failure patient for up to seven years. However, continuous?flow physiology causes a reduction in pulse pressure and increase the mean aortic pressure at higher pump rotational speeds which in turn results in pathological pressure overload above the aortic valve, consequently causing aortic valve thrombosis, fusion and/or regurgitation in 20 percent to 50 percent of the LVAD implanted patients.
The physiological (or pathological, if any) effects of the continuous flow and reduced pulsatility on myocardial perfusion is still not well understood as well which is very important mostly in patients supported for myocardial recovery (bridge to recovery). Therefore, to increase the survival of those patients and improve their quality of life, a better understanding of the continuous flow physiology is necessary to provide optimal flow conditions with the ventricular assist devices.
In this presentation, the effects of the continuous flow assist devices will be discussed under the light of the previous and current literature.