Left Ventricular Flow Dynamics with the HeartMate3 Left Ventricular Assist Device: Effect of Inflow Cannula Position...

Area of Science:

• Cardiovascular Engineering
• Biomedical Fluid Dynamics
• Medical Device Design

Background:

• Improper left ventricular assist device (LVAD) inflow cannula (IC) positioning can lead to blood stasis and low pulsatility, increasing thromboembolism risk.
• LVAD speed modulation is a potential strategy to mitigate these risks associated with suboptimal IC placement.

Purpose of the Study:

• To investigate how left ventricle (LV) flow architecture is affected by IC position and LVAD speed modulation in HeartMate3 devices.
• To assess the sensitivity of LV flow dynamics to variations in IC angulation and insertion depth.

Main Methods:

• A mock loop study using a transparent silicone LV model was conducted.
• Measurements included system pressure, flow, and time-resolved velocity fields under varying IC angles and insertion depths.
• HeartMate3 support was simulated at matched cardiac function and LVAD speeds.

Main Results:

• Angling the IC towards the septum increased LVAD flow resistance and enhanced the counter-clockwise (CCW) vortex, while reducing apical velocity.
• Increased IC protrusion decreased flow resistance and apical pulsatility but increased IC velocity.
• Higher LVAD flow resistance improved aortic valve opening and strengthened the CCW vortex, promoting higher blood residence time.

Conclusions:

• HeartMate3 speed modulation showed minimal reduction in pulsatility despite significant impacts on LV flow architecture due to IC positioning.
• Understanding IC positioning effects is vital for optimizing LVAD performance and minimizing thromboembolic events.