Mechanical Circulatory Support of the Right Ventricle for Adult and Pediatric Patients With Heart Failure.

The clinical implementation of mechanical circulatory assistance for a significantly dysfunctional or failing left ventricle as a bridge-to-transplant or bridge-to-recovery is on the rise. Thousands of patients with left-sided heart failure are readily benefitting from these life-saving technologies, and left ventricular failure often leads to severe right ventricular dysfunction or failure. Right ventricular failure (RVF) has a high rate of mortality caused by the risk of multisystem organ failure and prolonged hospitalization for patients after treatment. The use of a blood pump to support the left ventricle also typically results in an increase in right ventricular preload and may impair right ventricular contractility during left ventricular unloading. Patients with RVF might also suffer from severe pulmonary dysfunction, cardiac defects, congenital heart disease states, or a heterogeneity of cardiophysiologic challenges because of symptomatic congestive heart failure. Thus, the uniqueness and complexity of RVF is emerging as a new domain of significant clinical interest that motivates the development of right ventricular assist devices. In this review, we present the current state-of-the-art for clinically used blood pumps to support adults and pediatric patients with right ventricular dysfunction or failure concomitant with left ventricular failure. New innovative devices specifically for RVF are also highlighted. There continues to be a compelling need for novel treatment options to support patients with significant right heart dysfunction or failure.

Hybrid Continuous-Flow Total Artificial Heart.

Clinical studies using total artificial hearts (TAHs) have demonstrated that pediatric and adult patients derive quality-of-life benefits from this form of therapy. Two clinically-approved TAHs and other pumps under development, however, have design challenges and limitations, including thromboembolic events, neurologic impairment, infection risk due to large size and percutaneous drivelines, and lack of ambulation, to name a few. To address these limitations, we are developing a hybrid-design, continuous-flow, implantable or extracorporeal, magnetically-levitated TAH for pediatric and adult patients with heart failure. This TAH has only two moving parts: an axial impeller for the pulmonary circulation and a centrifugal impeller for the systemic circulation. This device will utilize the latest generation of magnetic bearing technology. Initial geometries were established using pump design equations, and computational modeling provided insight into pump performance. The designs were the basis for prototype manufacturing and hydraulic testing. The study results demonstrate that the TAH is capable of delivering target blood flow rates of 1-6.5 L/min with pressure rises of 1-92 mm Hg for the pulmonary circulation and 24-150 mm Hg for the systemic circulation at 1500-10 000 rpm. This initial design of the TAH was successful and serves as the foundation to continue its development as a novel, more compact, nonthrombogenic, and effective therapeutic alternative for infants, children, adolescents, and adults with heart failure.