Abstract 9925: Impaired Cardiac Output and Peripheral Reserve Predict Morbidity and Mortality in Heart Failure and Preserved Ejection Fraction

Abstract

Introduction: Reduced peak oxygen consumption (VO 2 ) is common and associated with adverse outcomes in patients with heart failure (HF) and preserved ejection fraction (HFpEF). According to the Fick principle, VO 2 is equal to the product of cardiac output (CO) and arterial-venous O 2 difference (AVO 2 diff). Patients with HFpEF display abnormalities each component, but no study has yet evaluated their prognostic impacts. Methods: Patients with HFpEF (n=501) and controls without HF (n=207) underwent invasive hemodynamic exercise testing with expired gas analysis and clinical follow up for the composite event of HF hospitalization or death. Results: Compared to controls, patients with HFpEF displayed slightly lower CO at rest with higher pulmonary capillary wedge pressure (PCWP). On exercise, subjects with HFpEF displayed blunted increases in CO and greater increase in PCWP (Figure A). As compared with controls, the slope of the increase in CO relative to VO 2 was lower in HFpEF (6.4 ± 3.3 vs 5.4 ± 3.2 L/L; P =0.0004), while augmentation in AVO 2 diff relative to VO 2 was greater in HFpEF (7.7 ± 5.4 vs 10.0 ± 5.6 min/dL; P <0.0001). Over a median 2.8 (1.1-4.6) years of follow up, 101 patients experienced the composite event. Patients with CO reserve below the median and increases in AVO 2 diff below median displayed higher risk of the composite endpoint (Figure B-C). After adjustments for age, sex, BMI, atrial fibrillation, LV mass, and EF, CO reserve remained strongly associated with the primary outcome (HR [95%CI] = 0.51 [0.38-0.68]; P <0.0001, per 1 SD increase) and the change of AVO 2 diff remained significant, but was less predictive (HR [95%CI] = 0.74 [0.60-0.92]; P =0.007, per 1 SD increase) in patients with HFpEF. Conclusions: Impaired ability to augment CO and peripheral O 2 delivery are associated with increasing risk of adverse events in HFpEF. Further study is required to identify therapeutic interventions targeting these hemodynamic perturbations to improve outcomes in HFpEF.