Left Atrial Unloading in Heart Failure With Preserved Ejection Fraction: In-Vitro Study of Interatrial Shunting and...

Area of Science:

• Cardiovascular Physiology
• Medical Device Engineering

Background:

• Heart failure with preserved ejection fraction (HFpEF) is frequently associated with elevated left atrial (LA) pressure.
• Interatrial shunt devices (IASD) and off-label rotary blood pump use aim to alleviate LA pressure in HFpEF.

Purpose of the Study:

• To compare the efficacy of an IASD and a continuous flow (CF) centrifugal rotary blood pump in reducing LA pressure and pulmonary artery pressure (PAP) in a simulated HFpEF model.

Main Methods:

• A mock circulation loop simulating an HFpEF patient was used.
• Pulmonary decompression was assessed using an IASD (2-12 mm) and a HeartMate 3 CF pump (LA to aorta configuration, 1-6 L/min support).
• Key hemodynamic parameters including LA pressure, PAP, and cardiac output (CO) were measured at rest and during simulated exercise.

Main Results:

• Both devices reduced LA pressure and PAP. The CF pump demonstrated greater reductions in LA pressure (135% rest, 51% exercise) and PAP (57% rest, 32% exercise) compared to the IASD (28% rest, 45% exercise LA pressure; 13% rest, 21% exercise PAP).
• The CF pump significantly increased CO (63% rest, 28% exercise), whereas the IASD decreased CO (14% rest, 8% exercise).
• The CF pump's LA to aorta configuration increased ventricular loading.

Conclusions:

• Both IASD and CF rotary blood pumps can reduce LA pressure and PAP in a simulated HFpEF setting.
• CF rotary blood pumps offer superior pulmonary decompression and improve cardiac output, but increase ventricular loading.
• Dynamic adjustment of pump speed or IASD diameter could optimize unloading across different physiological states.