Prognostic Value of Cardiopulmonary Exercise Testing in Heart Failure With Reduced, Midrange, and Preserved Ejection Fraction

Background-This study aimed to compare the independent and incremental prognostic value of peak oxygen consumption (VO2) and minute ventilation/carbon dioxide production (VE/VCO2) in heart failure (HF) with preserved (HFpEF), midrange (HFmEF), and reduced (HFrEF) ejection fraction (LVEF). Methods and Results-In 195 HFpEF (LVEF >= 50%), 144 HFmEF (LVEF 40-49%), and 630 HFrEF (LVEF <40%) patients, we assessed the association of cardiopulmonary exercise testing variables with the composite outcome of death, left ventricular assist device implantation, or heart transplantation (256 events; median follow-up of 4.2 years), and 2-year incident HF hospitalization (244 events). In multivariable Cox regression analysis, greater association with outcomes in HFpEF than HFrEF were noted with peak VO2 (HR [95% confidence interval]: 0.76 [0.67-0.87] versus 0.87 [0.83-0.90] for the composite outcome, P-interaction=0.052; 0.77 [0.69-0.86] versus 0.92 [0.88-0.95], respectively for HF hospitalization, P-interaction=0.003) and VE/VCO2 slope (1.11 [1.06-1.17] versus 1.04 [1.03-1.06], respectively for the composite outcome, P-interaction=0.012; 1.10 [1.05-1.15] versus 1.04 [1.03-1.06], respectively for HF hospitalization, P-interaction=0.019). In HFmEF, peak VO2 and VE/VCO2 slope were associated with the composite outcome (0.79 [0.70-0.90] and 1.12 [1.05-1.19], respectively), while only peak VO2 was related to HF hospitalization (0.81 [0.72-0.92]). In HFpEF and HFrEF, peak VO2 and VE/VCO2 slope provided incremental prognostic value beyond clinical variables based on the C-statistic, net reclassification improvement, and integrated diagnostic improvement, with models containing both measures demonstrating the greatest incremental value. Conclusions-Both peak VO2 and VE/VCO2 slope provided incremental value beyond clinical characteristics and LVEF for predicting outcomes in HFpEF. Cardiopulmonary exercise testing variables provided greater risk discrimination in HFpEF than HFrEF.