LEV-VAD: COMPUTATIONAL DESIGN AND EXPERIMENTAL TESTING

Purpose:

Thousands of cardiac failure patients per year in the US could benefit from long-term mechanical circulatory support as destination therapy. To provide an improvement over currently available devices, we have designed a fully implantable axial flow ventricular assist device with a magnetically levitated impeller (LEV-VAD). In contrast to currently available devices, the LEV-VAD has an unobstructed blood flow path, generating substantially less retrograde and stagnant flow.

Methods:

The pump design included the extensive use of conventional pump design equations and computational fluid dynamics (CFD) modeling for predicting pressure-flow curves, hydraulic efficiencies, scalar fluid stress levels, and exposure times. Flow performance testing was completed on a plastic prototype of the LEV-VAD for comparison to the CFD predictions. Animal fit trials were completed to determine optimum pump location and cannulae configuration for animal implantations.

Results:

Per the CFD results, the LEV-VAD produces 6 lpm and 100 mmHg at a rotational speed of 6,300 RPM. The pressure-flow performance predictions demonstrated the VAD’s ability to deliver adequate flow over physiologic pressures. The CFD numerical estimations generally agree within 10% of the experimental measurements over the entire range of rotational speeds tested. Animal fit trials revealed that the LEV-VAD’s size and configuration were adequate requiring no alterations to cannulae configurations for future animal testing.