Prognostic value of VE/VCO slope in overweight heart failure patients.

BACKGROUND

A decreased hypercapnic ventilatory response of the overweight patients would lower the ventilation equivalent of carbon dioxide (VE/VCO) slope but worsen prognosis. The aim of this study was to compare the prognostic ability of the VE/VCO slope and peak oxygen consumption (pVO) between normal and overweight heart failure (HF) patients.

METHODS

Prospective evaluation of ambulatory patients with reduced left ventricular ejection fraction who underwent baseline assessment with a cardiopulmonary exercise test. The primary endpoint was cardiac death or urgent heart transplantation in the 5-year period of follow-up. The predictive power of VE/VCO slope and pVO were compared (area under the curve (AUC) analysis and Hanley & McNeil test), in the subgroups of patients with body mass index (BMI) of 18.5-24.9 kg/m and ≥ 25 kg/m. Statistical differences with a value < 0.05 were considered significant.

RESULTS

There were 270 enrolled patients, with a mean BMI of 27 ± 4 kg/m. No differences between normal and overweight patients (38.0% vs 29.8%, P=0.170) were found during the 5-year period for the primary endpoint. The VE/VCO slope was non-inferior to pVO in both groups at 1, 3 and 5 years of follow-up. The comparison of VE/VCO slope between groups revealed a significant lower AUC at 3 (0.921 vs 0.787, P=0.022) and 5 years (0.898 vs 0.787, P=0.044) of follow-up for overweight patients.

CONCLUSION

Despite VE/VCO slope provides a discriminative power at least as good as pVO for predicting adverse events in both normal and overweight HF patients, a significant lower predictive power was found in overweight patients.