Abstract 17245: Assessment of Contractility and Afterload Mismatch as Determinants of Reduced Ejection Fraction in Severe Aortic Stenosis
Background: Reduced LV ejection fraction (EF) in aortic stenosis (AS) is related to a decrease in contractility or afterload mismatch. Increase in afterload is due to reduced aortic valve area (AVA), changes in LV geometry and the characteristics of arterial vasculature.
Objective: To evaluate contractility and afterload mismatch as determinants of reduced EF in severe AS.
Methods: We studied 77 patients, age average 70 ± 10 years, 48 men, with severe AS (AVA < 1 cm2) and 63 normal control subjects with Doppler echocardiography. Contractility was assessed by midwall fractional shortening (mFS) - end-systolic stress (ESS) relation in control subjects, with regression equation: mFS = 28.15 - 0.12 x ESS , standard error of estimation (SEE) of 3.75 % (r=0.40 p< 0.001). For any ESS level, a value of mFS predicted by the regression equation below 2 SEE was considered as decreased contractility in patients with AS. Afterload mismatch was defined as EF < 50 % and contractility within normal range. Patients were divided into three groups: group 1, EF < 50 % and decreased contractility (n = 18), group 2, EF < 50 % and normal contractility (afterload mismatch) (n = 20 ) and group 3, EF ≥ 50 % and normal contractility (n = 39). Presence of heart failure (NYHA III-IV), symptoms (dyspnea I-II, angina, syncope), AVA, peak and mean gradient (PG, MG), valve resistance, energy loss index, valvulo-arterial impedance (Zva) and effective arterial elastance (Ea) were determined in three groups.
Results: see table There were not differences in AVA, valve resistance, energy loss index among three groups. In multivariate analysis Zva, Ea, PG and MG, were predictors of decreased contractility.
Conclusions: Patients with severe AS and reduced EF had similar proportion of decreased contractility, afterload mismatch and heart failure. Increase in vascular component of afterload evaluated by mean of Zva and Ea impacts significantly on contractility.
- © 2012 by American Heart Association, Inc.