Abstract 11461: The Hemodynamic Gain Index is an Independent Predictor of Adverse Outcomes, and Comparable to Peak Oxygen Consumption in Patients With Chronic Heart Failure With Reduced Ejection Fraction

Abstract

Introduction: The hemodynamic gain index (HGI) is a novel simple parameter calculated from resting and peak systolic BP (SBP) and heart rate (HR) during exercise testing. It is a predictor of mortality in population-based cohorts. However, the prognostic significance of the HGI in chronic HFrEF has not been well studied. Hypothesis: The HGI is independently associated with adverse outcomes, and is comparable to other cardiopulmonary exercise testing (CPET) parameters. Methods: Medical records of 1,067 consecutive HFrEF patients (EF ≤ 40%) undergoing CPET for symptom evaluation from 12/2012 to 9/2020 were reviewed. HGI was calculated using the formula, [(SBP peak x HR peak )-(SBP rest x HR rest )]/(SBP rest x HR rest ). Patients with missing vital signs, hypotensive or bradycardic response to exercise were excluded. Primary outcome was the composite endpoint of all-cause mortality, LVAD implantation, and heart transplantation. Multivariable Cox proportional hazard models were used with subgroup analyses based on median age, sex, BMI of 35 kg/m 2 , respiratory exchange ratio (RER) of 1.05, and beta-blocker use. ROC curves with AUCs were used to compare HGI, peak VO 2 , VE/VCO 2 slope and peak end-tidal pressure of CO 2 (PEtCO 2 ). Results: We included 954 HFrEF patients (mean age was 56.3 ± 12.0 years, 72% men, 17% with BMI ≥ 35 kg/m 2 , 86% on beta-blockers, and 73% with RER > 1.05). During a median follow up time of 946 days, the incidence of the composite outcome was 331 (34.7%). After adjustment for age, sex, BMI, comorbidities, and EF, higher HGI was independently associated with lower risk of the adverse outcomes in the main cohort (hazard ratio per unit increase 0.46, 95%CI 0.35 to 0.59, p < 0.001), and all subgroups, except for patients with BMI ≥ 35 kg/m 2 ( Figure 1A ). The HGI was also comparable to peak VO 2 , and outperformed VE/VCO 2 slope and PEtCO 2 ( Figure 1B ). Conclusions: The HGI is an independent predictor of adverse outcomes, and comparable to peak VO 2 in patients with chronic HFrEF.