Date of Award

January 2015

Document Type

Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Pramod Bonde

Subject Area(s)

Surgery, Biomedical engineering

Abstract

The current left ventricular assist device (LVAD) suffers from a high-risk implantation procedure in an extremely unstable group of advanced heart failure patients. In an effort to decrease this invasiveness, we have conceived a wireless percutaneous LVAD, capable of being delivered endovascularly with a tether free operation. The system obviates the need for a transcutaneous fluid purge line due to an incorporated magnetically coupled impeller for a complete seal. Our goal was to design, develop, simulate, and test a preliminary functioning prototype. Five prototypes were designed and constructed to iteratively minimize the pump size and improve fluid dynamic performance. Various magnetic coupling configurations were tested. Using SolidWorks and ANSYS software for modeling and simulation, several geometric parameters were varied. In this manner, we sought to increase output flow, decrease stasis, and decrease secondary flow. HQ curves to characterize the pump performance were constructed with CFD simulations as well as through in vitro testing. Bench top tests showed no-slip magnetic coupling of the impeller to the driveshaft up to the current limit of the motor. CFD simulations demonstrated a flow rate of 3.0 L/min for a pressure head of 100 mmHg at 20600 rpm, 5.0 L/min for a pressure head of 100 mmHg at approximately 23600 rpm, and 7.0 L/min for a pressure head of 100 mmHg at 26,600 rpm. HQ curves showed the ability to provide positive flows across a full physiological pressure range for speeds of 23600 rpm and 26600 rpm. The pump power requirements were tested in vitro and were within the appropriate range for powering via a wireless energy transfer system. Our results demonstrate the potential of a novel endovascular cardiac assist device to provide adequate physiological performance, with an ability to eventually offer patients an untethered, minimally invasive solution.

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