Gender and age normalization and ventilation efficiency during exercise in heart failure with reduced ejection...

Area of Science:

• Cardiology
• Exercise Physiology
• Pulmonary Medicine

Background:

• Ventilation vs. carbon dioxide production (VE/VCO2) slope is a key prognostic indicator in heart failure (HF).
• Current normal VE/VCO2 slope values are based on limited data, particularly lacking representation of women and the elderly.
• Standard prognostication often uses absolute VE/VCO2 slope values.

Purpose of the Study:

• To develop prediction formulas for VE/VCO2 slope in a large, diverse population.
• To assess if expressing VE/VCO2 slope as a percentage of predicted value impacts its prognostic power in HF patients compared to absolute values.

Main Methods:

• Calculated VE/VCO2 slope regressions against age in 1136 healthy individuals.
• Applied age- and sex-adjusted formulas to predict VE/VCO2 slope in 6112 HF patients.
• Compared the prognostic accuracy (2-year survival) of absolute vs. percentage predicted VE/VCO2 slope values in the overall HF cohort and in severe/moderate HF subgroups.

Main Results:

• Developed age- and sex-specific VE/VCO2 slope prediction equations for healthy individuals.
• In severe HF patients, the percentage of predicted VE/VCO2 slope showed significantly better prognostic accuracy (AUC 0.650) than absolute values (AUC 0.637).
• Using the percentage of predicted VE/VCO2 slope reclassified 6.6% of severe HF patients, improving risk stratification.

Conclusions:

• The percentage of predicted VE/VCO2 slope enhances prognostic power in severe HF patients and is preferable to absolute values.
• This refined metric can improve the identification of high-risk HF patients, a critical clinical objective.
• Widespread adoption of percentage predicted VE/VCO2 slope can advance HF management strategies.