• Costa, G. D.
• Barros, F. C.
• Milani, M.
• Garbin, H. I.
• Caceres, R. C.
• Leopoldino, G.
• Silveira, A. D.
• Milani, J. G. P. O.
• Saadi, M. P.
• Menegazzo, W. R.

Abstract

<jats:title>Abstract</jats:title><jats:sec><jats:title>Background</jats:title><jats:p>The oxygen uptake efficiency slope (OUES) serves as a prognostic measure derived from cardiopulmonary exercise testing (CPET) in heart failure. Various equations are utilized as references to calculate predicted OUES (1,2). Recently, a new equation, specifically derived from a South American population, has been validated (3). Nevertheless, a comprehensive comparative analysis between mortality prediction in heart failure using the percent-predicted approach based on these equations and absolute values remains to be addressed.</jats:p></jats:sec><jats:sec><jats:title>Purpose</jats:title><jats:p>To investigate and compare mortality prediction in heart failure using the percent-predicted approach and absolute values of the oxygen uptake efficiency slope (OUES), incorporating Hollenberg (1), Buys (2) and Milani (3) equations.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>This is a retrospective cohort study involving heart failure patients assessed at a tertiary university hospital from 2010 to 2022. All patients underwent symptom-limited maximal cardiopulmonary exercise testing (CPET) and regular follow-ups in a specialized outpatient clinic. The primary outcome was all-cause mortality. We performed a ROC curve analysis to compare the accuracy of the equations and absolute values and to determine the best cut-points. Cox proportional hazards regression was used to assess uni- and multivariate effects of different OUES metrics.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>A total of 1,219 patients were included, with 57% being male and a mean age of 55 ± 13 years. The median follow-up was 4.9 years (IQR 3.1 years), resulting in 157 deaths (13%). Ischemic heart disease was present in 31%, and the mean ejection fraction (EF) was 37 ± 15%. Based on EF classification, 66% had reduced EF, 10% had mildly reduced EF, and 24% had preserved EF. ROC curve analysis demonstrated similar accuracy for absolute values and all three equations (Figure 1). The overall model quality was 0.64 for Hollenberg and Buys equations, 0.63 for absolute values, and 0.62 for Milani equations. Absolute OUES had an unadjusted hazard ratio (HR) of 0.999, and percent-predicted OUES using Hollenberg had a HR of 0.973, Buys a HR of 0.967, and Milani a HR of 0.976 for death (P &amp;lt; 0.001 for all comparisons). All comparisons remained significant after age and sex adjustment (P &amp;lt; 0.001).</jats:p></jats:sec><jats:sec><jats:title>Conclusions</jats:title><jats:p>Our results demonstrate that the oxygen uptake efficiency slope (OUES), whether assessed through percent-predicted or absolute values, exhibits comparable accuracy in predicting mortality among heart failure patients. Distinct cut-offs were established for individual equations. The consistent significance of hazard ratios, even after adjustments for age and sex, underscores the robust prognostic value of OUES metrics. These findings highlight the potential of both OUES and percent-predicted OUES as valuable tools for mortality prediction in heart failure. ROC curve analysis.</jats:p></jats:sec>

Topics

• impedance spectroscopy
• Oxygen
• size-exclusion chromatography
• ultraviolet photoelectron spectroscopy