Two is better than one: the double diffusion technique in classifying heart failure.

Area of Science:

• Pulmonary Medicine
• Cardiology
• Diagnostic Imaging

Background:

• Heart failure (HF) is a chronic condition impacting the heart's pumping efficiency.
• Lung diffusing capacity measurements, specifically for nitric oxide (DLNO) and carbon monoxide (DLCO), reflect pulmonary gas exchange and may aid in HF classification.

Purpose of the Study:

• To evaluate if DLNO testing, in addition to DLCO, enhances HF prediction compared to DLCO alone.
• To determine if combining DLNO and DLCO z-scores improves binary HF classification over using DLCO z-scores solely.

Main Methods:

• Retrospective analysis of 140 NYHA Class II HF patients and 50 non-HF controls.
• Creation of z-scores for DLNO, DLCO, and combined DLNO+DLCO from established reference equations.
• Model selection using Bayesian Information Criterion and binary HF classification assessment via Matthews Correlation Coefficient (MCC).

Main Results:

• Combined DLNO and DLCO z-score models were the top performers among 12 evaluated models.
• The highest MCC of 0.51 was achieved using combined z-score models.
• Combined z-scores explained up to 32% of the variance in the odds of having HF.

Conclusions:

• Combined DLNO and DLCO z-scores demonstrated a higher predictive capability for HF than individual measurements.
• The NO-CO double diffusion technique shows moderate effectiveness in classifying HF patients.
• This technique is recommended for assessing gas exchange impairment in individuals suspected of having HF.