Elevated Oxygen Uptake Recovery Ratio In Heart Failure Has Poorer Prognostic Outcomes

Impaired recovery oxygen kinetics have been associated with greater prognostic risk in individuals with heart failure (HF). However, these parameters have not been routinely implemented into clinical practice when interpreting cardiopulmonary exercise tests (CPET). This study sought to identify a simple post-exercise oxygen kinetic parameter and assess prognostic outcomes in individuals with HF.

Individuals with HF who underwent CPET were assessed. A novel parameter, oxygen consumption recovery ratio (V˙O₂RR), defined as the ratio of the V˙O₂ measured 10-40 seconds post-exercise (V˙O_2recovery) to V˙O_2peak, was used to assess V˙O₂ recovery. The ability of V˙O₂RR to predict major cardiac-related events (death, left ventricular assist device transplantation, or cardiac transplantation) within 24 months of CPET was examined.

A total of 140 individuals with HF were included. When stratified by a V˙O₂RR ≥1.00, those with a higher V˙O₂RR demonstrated worse exercise capacity and ventilatory efficiency (V˙O_2peak: 18.4±6.0 vs 13.0±2.8 mL.min^-1.kg^-1; V˙_E/V˙CO₂ slope: 37.7±9.5 vs 41.7±8.0, respectively). A V˙O₂RR of ≥1.00 predicted poorer transplant-free survival in both univariate and multivariable logistic regression models (odds ratios were 14% and 8% per 0.01 increase in V˙O₂RR, respectively; both p<0.05).

The V˙O₂RR is an easily calculated parameter from a CPET that predicts outcomes in HF. Additionally, when combined with V˙O_2peak, the V˙O₂RR offers greater prognostic value in predicting outcomes in HF populations.