Impact of time past exercise testing on prognostic variables in heart failure

BackgroundCardiopulmonary exercise testing (CPET) is considered a standard of care in heart failure (HF). The impact that duration of time post-evaluation has on the prognostic value of CPET, however, has not been explored. The purpose of this investigation was to examine the ability of peak oxygen consumption (VO2) and the minute ventilation–carbon dioxide production (VE/VCO2) slope to predict cardiac-related events at different time intervals post CPET.MethodsTwo hundred fifty-eight subjects diagnosed with HF underwent CPET. The ability of peak VO2 and VE/VCO2 slope to predict cardiac-related events without a time limit, one year post CPET and greater than one year post CPET was examined. Results: Both peak VO2 and VE/VCO2 slope were significant predictors of cardiac-related mortality and hospitalization during the no time constraint and one year post CPET tracking scenarios (Hazard Ratio Range: 3.5–12.4, p < 0.001). Peak VO2 was no longer a significant predictor of mortality greater than one year post CPET. Generally, as time following CPET surpassed one year, the prognostic sensitivity of both variables slightly increased (∼5%) while specificity sharply decreased (∼20%).ConclusionsBoth peak VO2 and VE/VCO2 slope are significant predictors of cardiac-related events in HF. However, the prognostic characteristics of these variables following CPET appear to be time-sensitive.