Can we Further Stratify Heart Failure Patients Deemed to be at Intermediate Risk of Mortality⋯Looking Beyond Percent Predicted Peak VO2 and Ventilatory Efficiency?

Abstract

Background Percent predicted peak oxygen uptake (%ppVO2) is a useful tool to help stratify risk in patients with heart failure with reduced ejection fraction (HFrEF). However, insufficient knowledge on how to best optimize timing for advanced therapies in patients with a peak VO2 between 50% and 75% of predicted exists. Purpose Determine if risk for mortality can be further parsed in patients with a %ppVO2 between 50% and 75%, using the slope relationship between minute ventilation and carbon dioxide (VE/VCO2 slope) and clinical variables. Methods Retrospective analysis involving patients with HFrEF (EF Results 645 patients were included in this study: 66% male, 53% african american, mean (+sd) age 55+13, 63% non-ischemic etiology, and EF 23+10. There were 300 deaths over 6.4 median years of follow-up. For both 1 and 3 year mortality rates, we observed a significant difference across all three subgroups of VE/VCO2 slope ( Table 1 ) Table 2 lists those covariates that were independently associated with mortality for each subgroup of VE/VCO2 slope. No models could be identified to predict mortality with a sufficiently high degree of sensitivity and specificity. Conclusions Among patients with HFrEF at intermediate risk for mortality based on %ppVO2, an increase in VE/VCO2 is associated with increased risk for mortality and may identify patients in need of closer surveillance. However, no additional covariates or combinations of covariates could be identified to sufficiently further parse risk for any of the three VE/VCO2 subgroups.