We present a review of the evolution of total artificial hearts (TAHs) and new directions in development, including the coupling of VADs as biventricular TAH support.

No abstract

Limited treatment options for patients having dysfunctional single ventricle physiology motivate the necessity for alternative therapeutic options. To address this unmet need, we are developing a collapsible axial flow blood pump. This study investigated the impact of geometric simplicity to facilitate percutaneous placement and maintain optimal performance. Three new pump designs were numerically evaluated. A transient simulation explored the impact of respiration on blood flow conditions over the entire respiratory cycle. Prototype testing of the top performing pump design was completed. The top performing Rec design generated the highest pressure rise range of 2-38 mm Hg for flow rates of 1-4 L/min at 4000-7000 RPM, exceeding the performance of the other two configurations by more than 26%. The blood damage indices for the new pump designs were determined to be below 0.5% and predicted hemolysis levels remained low at less than 7 × 10(-5)  g/100 L. Prototype testing of the Rec design confirmed numerical predictions to within an average of approximately 22%. These findings demonstrate that the pumps are reasonably versatile in operational ability, meet pressure-flow requirements to support Fontan patients, and are expected to have low levels of blood trauma.

An intravascular axial flow pump is being developed as a mechanical cavopulmonary assist device for adolescent and adult patients with dysfunctional Fontan physiology. Coupling computational modeling with experimental evaluation of prototypic designs, this study examined the hydraulic performance of 11 impeller prototypes with blade stagger or twist angles varying from 100 to 600 degrees. A refined range of twisted blade angles between 300 and 400 degrees with 20-degree increments was then selected, and four additional geometries were constructed and hydraulically evaluated. The prototypes met performance expectations and produced 3-31 mm Hg for flow rates of 1-5 L/min for 6000-8000 rpm. A regression analysis was completed with all characteristic coefficients contributing significantly (P< 0.0001). This analysis revealed that the impeller with 400 degrees of blade twist outperformed the other designs. The findings of the numerical model for 300-degree twisted case and the experimental results deviated within approximately 20%. In an effort to simplify the impeller geometry, this work advanced the design of this intravascular cavopulmonary assist device closer to preclinical animal testing.