Valvular Regurgitation in a Biventricular Mock Circulatory Loop

Area of Science:

• Cardiovascular Engineering
• Biomedical Engineering
• Hemodynamics

Background:

• Valvular regurgitation, including aortic (AR), mitral (MR), and tricuspid (TR), is a common complication following continuous-flow left ventricular assist device (LVAD) implantation.
• The incidence of these valvular issues may increase with prolonged LVAD support, impacting device efficacy and patient outcomes.

Purpose of the Study:

• To simulate severe AR, MR, and TR in a mock circulatory loop (MCL) to assess their impact on isolated LVAD and biventricular assist device (BiVAD) performance.
• To evaluate the effects of varying LVAD pump speed and preload on hemodynamic parameters under simulated regurgitant conditions.

Main Methods:

• A 4-elemental pulsatile mock circulatory loop (MCL) was utilized to simulate isolated LVAD and BiVAD (HeartWare HVAD) support.
• Severe AR, MR, and TR were induced by removing a leaflet from mechanical heart valves.
• LVAD pump speed (2200-4000 RPM) and preload (10-25 mmHg) were systematically altered.

Main Results:

• All simulated regurgitant valve lesions led to a decrease in isolated LVAD pump flow pulsatility.
• Isolated LVAD provided adequate support for severe MR and TR, with enhanced flow under BiVAD support.
• Severe AR showed no benefit from BiVAD support over isolated LVAD, with consistently low loop flows. High LVAD flow, low RVAD flow, and low aortic pressure indicated AR.

Conclusions:

• The MCL effectively simulated valvular conditions and assessed device performance.
• Conservative management of MR and TR is supported in patients with mechanical circulatory support.
• Correction of AR is crucial in patients with LVADs to ensure adequate hemodynamic support and device function.