Abstract Body (Do not enter title and authors here): Background: Cardiopulmonary exercise testing (CPET) remains an important test for risk assessment in ambulatory heart failure patients to identify those who may benefit from advanced therapies, such as left ventricular assist device (LVAD) or heart transplantation (HT). The prognostic strength of cardiac performance variables at peak exercise, including oxygen consumption (VO₂), oxygen pulse (O₂ pulse) and circulatory power (CP) is known. We explored the prognostic utility of augmentation of these parameters between resting and peak stress conditions.
Methods: We performed a retrospective analysis of ambulatory heart failure patients from the National Heart, Lung, Blood Institute funded REVIVAL and our institutional PREDICT-HF databases. Patients with heart failure that underwent CPET and ≥ 1-year of follow-up were included. The primary outcome was a composite of death, HT, or LVAD at 1-year following CPET. The absolute change (Δ) in CPET variables was defined as the difference between resting and peak values.
Results: A total of 351 patients from PREDICT-HF (n=110) and REVIVAL (n=241) were included; mean age 58, 70% male, 31% Black, 59% non-ischemic, median NYHA functional class 3, median INTERMACS profile 6, and mean LVEF 26%. At 1-year, there were 61 events (17%), which included 20 deaths, 19 HTs, and 22 LVAD implants. The ΔVO₂, ΔO₂ pulse, and ΔCP were all higher in the non-event group (all p<0.001). The ΔVO₂ (odds ratio [OR]) 0.92; 95% CI 0.87-0.97; p = 0.006), ΔO₂ pulse (OR 0.85; 95% CI 0.76-0.93; p = 0.001), and ΔCP (OR 0.48; 95% CI 0.31-0.70; p<0.001) were significant predictors of the primary outcome on univariate analysis. Only ΔO₂ pulse (OR 0.85 vs. 0.89) performed better on univariate analysis when compared to its peak counterpart. Peak CP (OR 0.37) remained the strongest predictor overall.
Conclusions: The absolute change between resting and peak VO₂, O₂ pulse, and CP were predictive of death, HT, or LVAD at 1-year. Further multivariate analysis and comparative statistics assessing the prognostic utility of augmentation of these parameters compared to isolated peak values are needed to determine clinical utility.