Abstract 12327: Impact of Aortic Stiffness on Exercise Intolerance in Patients With Reduced Left Ventricular Ejection Fraction
Exercise intolerance assessed by peak oxygen consumption (peak VO2), is a powerful independent predictor of all-cause mortality in patients with heart failure. Exercise intolerance is generally considered to be associated with left ventricular (LV) diastolic dysfunction. In addition, increased aortic stiffness has also been known as a restricting factor of exercise capacity in patients with preserved LV ejection fraction (LVEF). Recently, the cardio-ankle vascular index (CAVI) has been proposed as a new noninvasive parameter of aortic stiffness which is independent of blood pressure. CAVI = a[ρ/ΔPх[ln Ps/Pd] PWV2]+b (a, b, constant; ρ, blood density; ΔP, difference in systolic and diastolic pressure; Ps, systolic pressure; Pd, diastolic pressure; PWV, heart-ankle pulse wave velocity). Accordingly, we examined whether elevated aortic stiffness evaluated by the heart-ankle PWV and CAVI was crucial to explain exercise intolerance in patients with reduced LVEF (LVEF≤50%).
Methods: Twenty four patients with reduced LVEF who referred to cardio-pulmonary exercise testing for clinical reasons were enrolled (age 65.2 ± 9.9 years; male 62.5%). Before testing, comprehensive Doppler echocardiography was carried out. Early diastolic transmitral velocity (E) and mitral annular velocity during early diastole (e’) were measured. Plasma B-type natriuretic peptide (BNP) levels were obtained.
Results: Peak VO2 had significant inverse correlations with the CAVI (r=-0.47, p=0.02), PWV (r=-0.46, p=0.02), E/e’(r=-0.41, p=0.048), age (r=-0.54, p=0.007), and BNP (r=-0.43, p=0.04). In multivariate regression model including the CAVI, age (β=-0.49, p=0.01) and E/e’ (β=-0.44, p=0.02) were selected as determinants for peak VO2. In another model including the PWV but not the CAVI, age (β=-0.49, p=0.01) and E/e’ (β=-0.44, p=0.02) were selected as determinants for peak VO2. In either model, the CAVI (p=0.55) or PWV (p= 0.25) were not selected.
Conclusions: Increased arterial stiffness was inversely correlated with exercise capacity. However, neither the CAVI nor PWV have significant power to predict peak VO2. LV diastolic dysfunction is more important than elevated aortic stiffness to explain exercise intolerance in patients with reduced LVEF.
- © 2013 by American Heart Association, Inc.