Prognostic significance of cardiopulmonary exercise testing parameters for predicting all-cause mortality in patients with heart failure: a cohort study.

BACKGROUND: Heart failure (HF) remains a significant challenge in global healthcare, contributing to frequent hospitalizations and elevated mortality rates. Cardiopulmonary exercise testing (CPET) provides a non-invasive method of assessing how the cardiovascular, respiratory, and musculoskeletal systems function. OBJECTIVES: To evaluate whether CPET-derived measures predict all-cause mortality in patients with HF. METHODS: A prospective cohort study involving 247 consecutive patients with HF (mean 57 (13) years, 71% males), was conducted; 170 (69%) patients were characterised as HFrEF and 77 (31%) patients as HFpEF (n=52) or HFmrEF (n = 25). Mean left ventricular ejection fraction (LVEF) was 36.4% (10.6), and 73 patients (29.5%) had an LVEF <35%. All patients underwent a CPET examination. RESULTS: The median follow-up period was 3 years (range 1 to 9). All-cause mortality was 45 deaths out-of 247 patients (18.2%). After adjustments for age, sex, HF phenotype, presence of cardiomyopathy, and creatinine, NT-proBNP levels, only OUES remained an independent predictor of all-cause mortality in the entire cohort (Hazard Ratio 0.997, 95% Confidence Interval (0.996, 0.998); p=0.001), but not on those with submaximal CEPT. OUES below 1900 mL/min constitute a threshold associated with worse survival. CONCLUSION: Oxygen uptake-derived indices, particularly OUES, emerged as significant predictor of prognosis among patients with HF, regardless of LVEF, reflecting the overall efficiency of oxygen transport and utilization.