Intraventricular flow patterns and stasis in the LVAD-assisted heart.

Area of Science:

• Cardiovascular Science
• Biomedical Engineering
• Fluid Dynamics

Background:

• Left ventricular assist devices (LVADs) are crucial for heart failure management.
• LVADs alter intracardiac blood flow, potentially leading to adverse events like thrombosis.
• Understanding flow dynamics within the left ventricle (LV) during LVAD support is critical for device optimization and patient safety.

Purpose of the Study:

• To quantitatively assess alterations in left ventricular (LV) blood flow patterns under LVAD support.
• To investigate the impact of LVADs on vortex dynamics and fluid stasis within the LV.
• To correlate altered flow patterns with the risk of thrombus formation.

Main Methods:

• Utilized particle image velocimetry (PIV) in a mock circulatory loop simulating LVAD-assisted cardiac function.
• Analyzed flow patterns, vortex development, circulation, and kinetic energy in both pre-LVAD and LVAD-supported conditions.
• Quantified regions of fluid stasis, particularly near the left ventricular outflow tract.

Main Results:

• LVAD support did not significantly alter baseline vortex formation but increased vortex circulation and kinetic energy with higher LVAD speeds.
• A notable region of fluid stasis developed near the left ventricular outflow tract as pulsatility decreased and aortic valve opening ceased.
• These flow alterations were more pronounced with reduced cardiac function.

Conclusions:

• LVAD support primarily impacts flow dynamics by inducing stasis near the LV outflow tract, rather than fundamentally changing vortex behavior.
• The identified region of stasis is a key factor contributing to the increased risk of thrombus formation in LVAD patients.
• Further research into flow modification strategies may mitigate LVAD-related thrombotic complications.