AORTIC STENOSIS AND HEART FAILURE: DIFFERENCES AND SIMILARITIES BEYOND PRESERVED EJECTION FRACTION

Abstract

Objective: Degenerative aortic stenosis (AS) is highly prevalent in Western countries and shows a strong association with age and other cardiovascular risk factors such as arterial hypertension, diabetes mellitus, dyslipidaemia, and visceral obesity. The same risk factors are involved in the development of heart failure with preserved ejection fraction (HFpEF). Notwithstanding several similarities, patients with AS and preserved left ventricular ejection fraction (ASpEF) are not considered to actually have HFpEF. We sought to investigate the haemodynamic and metabolic features of patients with ASpEF both at rest and during physical effort and highlight similarities and differences with HFpEF. Design and method: We enrolled 148 patients with HFpEF, 150 with ASpEF (with at least moderate aortic transvalvular gradient), and 80 age- and sex-matched healthy controls. All patients received a comprehensive laboratory evaluation, a resting echocardiographic examination, and a combined cardiopulmonary-echocardiographic stress test. Patients with ASpEF who fulfilled the criteria for transcatheter aortic valve replacement (n=125) underwent cardiac computed tomography to measure aortic valve calcium score and volume. Results: Serum levels of N-terminal prohormone of brain natriuretic peptide were similar between HFpEF and ASpEF patients after excluding subjects with atrial fibrillation. As a marker of deregulated inflammation, epicardial adipose tissue (EAT) thickness was significantly greater in ASpEF than HFpEF and controls and was inversely related to peak oxygen consumption (VO2) in all subgroups (Figure). Furthermore, all patients showed a significant impairment in peak VO2 caused by a reduction in bith cardiac output (CO) and peripheral arteriovenous oxygen difference (AVO2diff). HFpEF patients displayed increased arterial stiffness, worse left ventricular-arterial coupling, and worse left atrial function. On the other hand, patients with ASpEF showed worse right ventricular-pulmonary arterial coupling. In ASpEF, disease severity, evaluated by aortic transvalvular peak velocity, mean gradient at rest and peak exercise, and aortic valve calcium score and volume, was directly related to EAT thickness. Conclusions: ASpEF shows substantial similarities to HFpEF. ASpEF could represent a separate phenotype in the spectrum of HFpEF; further and larger studies should investigate this hypothesis to give further insight into the pathophysiology of ASpEF.