Prognostic Value of Hemodynamic Gain Index in Patients With Heart Failure With Reduced Ejection Fraction

Background: Assessment of functional capacity in patients with heart failure with reduced ejection fraction (HFrEF) is essential for risk stratification, and it traditionally relied on cardiopulmonary exercise testing (CPET)–derived peak oxygen consumption (peak VO₂). Objectives: This study sought to investigate the prognostic value of alternative nonmetabolic exercise testing parameters in a contemporary cohort with HFrEF. Methods: Medical records of 1,067 consecutive patients with chronic HFrEF who underwent CPET from December 2012 to September 2020 were reviewed for a primary outcome that was a composite of all-cause mortality, left ventricular assist device implantation, and/or heart transplantation. Multivariable Cox regression and log-rank testing were used to determine prognostic values of various exercise testing variables. Results: The primary outcome was identified in 331 of 954 patients (34.7%) of the HFrEF cohort (median follow-up time, 946 days). After adjustment for demographics, cardiac parameters, and comorbidities, higher hemodynamic gain index (HGI) and peak rate-pressure product (RPP) were associated with greater event-free survival (adjusted HR per doubling: 0.76 and 0.36; 95% CI: 0.67-0.87 and 0.28-0.47; all P < 0.001, respectively). Moreover, HGI (area under the curve [AUC]: 0.69; 95% CI: 0.65-0.72) and peak RPP (AUC: 0.71; 95% CI: 0.68-0.74) were comparable to the standard peak VO₂ (AUC: 0.70; 95% CI: 0.66-0.73; P for comparison = 0.607 and 0.393, respectively) for primary outcome discrimination. Conclusions: HGI and peak RPP show good correlation with peak VO₂ in terms of prognostication and outcome discrimination in patients with HFrEF and may serve as suitable alternatives to CPET-derived prognostic variables.