The ShuttlePump is a novel implantable total artificial heart (TAH) concept based on a Linear-Rotary Actuator (LiRA) and currently under development at the Power Electronic Systems Laboratory, ETH Zurich in close partnership with Charit´e Berlin and the Medical University of Vienna. This paper presents the analysis, design and realization of the ShuttlePump Linear Actuator (LA) part, which is necessary to provide about 45 N of axial actuation force. Design criteria are minimization of volume and generated power losses in the winding, which could result in excess heating and/or blood damage, i.e. protein denaturation and aggregation. The LA is implemented as a Tubular LA (TLA) to maximize the active area for linear/axial force generation. After a preliminary analysis based on first principles, the TLA is optimized in detail with the aid of FEM simulations. The experimental measurements conducted on the realized TLA prototype verify the FEM simulation results and confirm the suitability for the realization of the ShuttlePump TAH.

Objective: Total artificial hearts (TAH) are used as a temporary treatment for severe biventricular heart failure. Long-term cardiac replacement is hampered by limited durability and complication rates, which may be attributable to the modus operandi of state-of-the-art pumping systems. The aim of this study was to assess the feasibility of a novel valveless pumping principle for a durable pulsatile TAH (ShuttlePump). Methods: With a rotating and linearly shuttling piston within a cylindrical housing with 2 in- and outlets, the pump features only one single moving part and delivers pulsatile flow to both systemic and pulmonary circulation. The pump and actuation system were designed iteratively based on analytical and in silico methods, utilizing finite element methods (FEM) and computational fluid dynamics (CFD) Pump characteristics were evaluated experimentally in a mock circulation loop mimicking the cardiovascular system, while hemocompatibility related parameters were calculated numerically. Results: Pump characteristics cover the entire required operating range for a TAH (2.5 - 9L/min at 50 - 160mmHg arterial pressures) at stroke frequencies of 1.5 - 5Hz while balancing left and right atrial pressures. FEM analysis showed a mean overall copper losses of 8.84W, resulting in local blood temperature rise of < 2k. The CFD results of normalized index of hemolysis was 3.57 mg/100L and 95% of the pumps blood volume was exchanged after 1.42s. Conclusion: This study indicates feasibility of a novel pumping system for a TAH with numerical and experimental results substantiating further development of the ShuttlePump.