Clinical Outcomes and Haemodynamics: High Output Heart Failure Versus Heart Failure With Preserved Ejection Fraction

BACKGROUND/AIMS High-output heart failure (HOHF) is an under-recognised and understudied variant form of cardiac failure characterised by increased cardiac output (CO), low systemic vascular resistance, and higher filling pressures. This study aimed to compare mortality, morbidity, and haemodynamic profiles of patients with HOHF with those of patients with heart failure with preserved ejection fraction (HFpEF). METHOD Patients diagnosed with HFpEF who underwent invasive haemodynamic assessment in the United States Veterans Affairs (VA) health system between 2007 and 2022 were divided into two groups based on the cardiac index (CI)/output-to-HOHF group and control group, respectively. We compared all-cause mortality, any hospitalisation, heart failure hospitalisations, and a composite outcome including mortality and rehospitalisations (within and outside the VA Health Care System) from the date of right heart catheterisation (RHC) to 1-year post-RHC or end of follow-up. Haemodynamics and clinical characteristics were also compared. RESULTS A total of 116,229 patients with RHC were screened, and 13,422 were included for analysis. A total of 450 patients had CO ≥8 L/min and CI >4 L/min/m2 (study group); 12,972 had CO <8 L/min or CI ≤4 L/min/m2 (control group). There were no noticeable differences in the described outcomes between groups. Patients who died were older or had a higher prevalence of obstructive lung disease, alcohol abuse, tobacco abuse, atrial fibrillation, or liver disease. CONCLUSIONS Despite distinct differences in pathophysiology and haemodynamics, our novel study findings suggest that HOHF is not associated with a noticeable difference in morbidity or mortality from that in patients with HFpEF.