Determinants of the Left Ventricular Ejection Fraction in Patients with Severe Aortic Stenosis

Background: In severe aortic stenosis (AS), reduced left ventricular ejection fraction (LVEF) (<50%) may be attributed to decreased contractility, afterload mismatch (AM) or a combination of both mechanisms.However, when LVEF is ≥50% some patients may have decreased contractility.Objective: The aim of this study was to assess contractility level (CL), AM and ventricular geometry as determinants of LVEF in patients with severe AS.Methods: Doppler echocardiography was used to study 184 patients with severe AS and 71 normal individuals (N).Contractility was assessed as the difference between measured and predicted midwall fractional shortening (mFS) minus 2 standard errors for an established meridional end-systolic stress (ESS).Patients with AS were divided into 4 groups: LVEF <50% (n=78), LVEF 50-59% (n=27), LVEF 60-69% (n=45), and LVEF ≥70% (n=34).Results: Decreased CL was observed in approximately half of the patients with LVEF <60% and in a lesser degree in patients with LVEF ≥60%.Afterload mismatch was found in patients with LVEF <50% with decreased (34%) as well as preserved (45%) CL.Conclusions: Half of the patients with LVEF <60% presented decreased CL and to a lesser extent this occurred in the rest of the patients, even with LVEF ≥70%.The overestimation of systolic function using LVEF seems to be related to the degree of concentric hypertrophy.