Echocardiographic elastic properties of ascending aorta and their relationship with exercise capacity in patients with non-ischemic dilated cardiomyopathy

Background

: Aortic stiffness, an independent predictor of mortality and cardiovascular events, is common among patients affected by non-ischemic dilated cardiomyopathy (NIDC) and heart failure (HF).

Methods

: A total of 55 patients with diagnosis of NIDC (aged 60 ± 11 years, mean ejection fraction (EF) 35.2% ± 7.7%) admitted consecutively to our department for mild to moderate HF (NYHA class II–III) underwent an echocardiographic study and cardiopulmonary exercise test (CPX). We evaluated elastic properties of ascending aorta, i.e. aortic stiffness and aortic distensibility (mm Hg^{− 1}), derived from ascending aorta systolic and diastolic diameter (mm/m²) measured 3 cm above the valvular plane through 2D-guided M-mode echocardiography.

Results

: Mean aortic stiffness was 15.63 ± 14.53 and aortic distensibility was 2.61 ± 2.39 mm Hg^{− 1}. Collected parameters at CPX were peak oxygen consumption (pVO₂) (ml/kg/min), anaerobic threshold (AT) and the slope of the relation between minute ventilation (VE) and carbon dioxide production (VCO₂). Mean pVO₂ was 15.4 ± 3.9 ml/kg/min, VE/VCO₂ ratio at AT was 36.1 ± 6.1. Functional capacity measured through peak VO₂ was found to be directly correlated with aortic distensibility (r = 0.47, p = − 0.0002) and negatively correlated to aortic stiffness index (r = − 0.51, p = − 0.0001). These results were the same at multivariate analysis, corrected by age, hypertension, diabetes mellitus and ejection fraction (respectively r = 0.27, p = 0.008 and r = − 1.75, p = 0.0002).

Conclusions

: HF patients due to NIDC elastic properties of ascending aorta, evaluated by echocardiography, are correlated with a reduced functional capacity.