Development of a Pediatric cardiac assist Maglev pump for use with a universal driver system.

Abstract

Heart failure (HF) remains the leading cause of death, affecting 26 million adults worldwide and 6.5 million adults in the United States. Pediatric HF patients have been a historically underserved population with few options for mechanical circulatory support (MCS) therapy, a leading treatment as an alternative to heart transplantation. To address this clinical need, the Inspired Universal MagLev System is being developed; a low cost, universal magnetically levitated extracorporeal MCS system with interchangeable single-use pumps that will ultimately provide adult and pediatric patients ventricular and respiratory assist therapies. The Inspired Pediatric VAD is the first single-use pump application for this MCS system and is specifically designed for pediatric circulatory support. This dissertation describes the development efforts to design and evaluate iterative impeller and pump housings for the Inspired Pediatric VAD. Requirements for the Inspired Pediatric VAD design include the need to generate the appropriate hemodynamic parameters (pressures and flows) for pediatric patients, and miniaturization of the pump and impeller to accommodate the pediatric population. Traditional pump theory and design methods were applied to aid in the unique design of the VAD impeller and pump housing, resulting in multiple design iterations. Two impeller and pump designs (V1, V2) were virtually constructed using computer-aided design (CAD) software. Three-dimensional flow and pressure features were analyzed using computational fluid dynamics (CFD) analysis. Simulated pump designs (V1, V2) were operated at 15% higher rotational speeds (~5000 rpm) than initially estimated (4255 rpm) to achieve the desired operational point (3.5 L/min flow at 150 mmHg). V2 design outperformed V1 by generating up to 30% higher pressures at all simulated rotational speeds and with 5% lower priming volume. Simulated hydrodynamic performance (flow, pressure and hydraulic efficiency) of VAD V2 compared favorably to current commercially available MCS devices. A prototype of the Inspired Pediatric VAD V2 was fabricated, the magnitude and range of hydraulic torque and forces of the impeller were quantified, and the hydrodynamic performance benchmarked. A static mock flow loop model containing a heated blood analogue solution was created to test the pump over a range of rotational speeds (500 - 6000 RPM), flow rates (0 - 3.5 L/min), and pressures (0 to ~420 mmHg). The device was initially powered by a shaft driven DC motor, which was used to calculate the fluid torque acting on the impeller. Additional CFD simulations of VAD V2 were compared against the empirical bench-top data at select rotational speed and