Hemodynamic Improvement with Application of Mechanical Circulatory Support in Heart Failure with Preserved Ejection Fraction in a Mock Circulation Loop

Abstract

Purpose Mechanical circulatory support (MCS) is a non-obvious therapy for heart failure with preserved ejection fraction (HFpEF) because ventricular systolic function is not reduced. We hypothesize MCS of the left ventricle (LV) or left atrium (LA) can improve the hemodynamics in HFpEF including when pulmonary arterial hypertension (PH) is present. Methods Hemodynamic conditions of HFpEF ± PH were recreated on a mock circulation loop (MCL) with a tunable resistance, arterial compliance, peripheral resistance, inertance, venous compliance, and replication of the Frank-Starling mechanism. Hemodynamic parameters were recorded, including atrial and ventricular pressures, ventricular volumes, ejection fraction, and cardiac output. A HeartWare HVAD™ (Medtronic, MN) was used in two different support configurations: 1) LV to aorta (Ao) and 2) LA to Ao. The pump speed was titrated to achieve systemic flow (Qs) of 4.0 L/min and 4.5 L/min. Results Conditions typically seen in patients with HFpEF ± PH were created in the MCL with complete hemodynamic profiles including HVAD support seen in Table1. In both configurations and regardless of PH status, further Qs augmentation was associated with a reduction in LV end-diastolic pressure, LA pressure and mean pulmonary artery pressure. In the LV to Ao configuration, LV volumes decreased, and ejection fraction improved. In the LA to Ao configuration, LV volumes increased. In the LV to Ao configuration, pressure-volume loop (PVL) data show a reduction in pressure-volume area including a decrease in both stroke work and potential energy. In LA to Ao configuration, PVL data show a decrease in stroke work but an increase in potential energy. This study was not designed to evaluate for suction events. Conclusion In HFpEF ± PH, MCS can increase Qs and reduce LA pressure. As compared to LV decompression, LA decompression does not volume unload the LV. This study shows potential for MCS as a therapeutic alternative for HFpEF.