Interaction between alveolar diffusing capacity and B-lines in heart failure with preserved ejection fraction - A...

Area of Science:

• Cardiology
• Pulmonary Medicine
• Exercise Physiology

Background:

• Heart failure with preserved ejection fraction (HFpEF) is characterized by elevated left atrial pressures.
• Exercise exacerbates pulmonary venous pressures and lung interstitial fluid accumulation in HFpEF patients.
• The relationship between resting pulmonary diffusing capacity and exercise-induced pulmonary congestion in HFpEF has not been fully explored.

Purpose of the Study:

• To investigate the association between resting pulmonary diffusing capacity and exercise-induced pulmonary congestion in patients with HFpEF.
• To analyze the subcomponents of pulmonary diffusing capacity, including alveolar-capillary membrane conductance (Dm) and capillary volume (Vcap).

Main Methods:

• Studied 40 stable HFpEF patients and healthy controls.
• Measured lung diffusing capacity for carbon monoxide (DLCO), Dm, and Vcap at rest.
• Assessed lung interstitial fluid (B-lines) and left ventricular filling pressures during combined Stress Echocardiography and Cardiopulmonary Exercise Test (ESE-CPET).

Main Results:

• HFpEF patients had lower resting DLCO and Dm compared to controls.
• HFpEF patients exhibited increased peak exercise B-lines, significantly correlated with resting DLCO and Dm.
• Resting Dm correlated negatively with VE/VCO2 slope and E/e' at peak exercise, indicating ventilatory/perfusion mismatch and elevated filling pressures.

Conclusions:

• Altered resting pulmonary gas exchange capacity and excessive lung extravascular water contribute to impaired exercise performance in HFpEF.
• Further mechanistic studies are needed to elucidate the cause-effect relationship between these physiological variables in HFpEF.