title: Impact of left ventricular outflow tract ellipticity on the grading of aortic stenosis in patients with normal ejection fraction.
abstract: BACKGROUND
  The pathophysiology of paradoxical low-gradient (LG) severe aortic stenosis (SAS) remains controversial. As low transvalvular flow has been implicated, we sought to investigate the impact of left ventricular outflow tract (LVOT) ellipticity on the estimation of the LV stroke volume, the calculation of the aortic valve area (AVA) by use of the continuity equation and on AS severity grading.
  
  
  METHODS
  We studied 190 consecutive patients (mean age: 72 ± 13 years; male: 57%) with SAS (indexed AVA < 0.6 cm2/m2) and preserved LV ejection fraction, including 120 patients with severe high gradient (HG) AS and 70 with severe paradoxical LG-AS. AS severity, LV volumes and LVOT ellipticity were assessed by 2D-Doppler echocardiography and cardiac magnetic resonance (CMR).
  
  
  RESULTS
  The LVOT exhibited an elliptical shape on CMR images, with a shorter anterior-posterior than median-lateral diameter (2.2 ± 0.2 vs 2.8 ± 0.3 cm, p < 0.01). Accordingly, the LVOT area measured by planimetry was larger than by 2D-echocardiography, assuming a circular orifice (4.9 ± 0.9 cm2vs 3.7 ± 0.8 cm2, p < 0.01). Inputting the elliptical LVOT area into the continuity equation resulted in a 29% increase in the indexed AVA (from 0.41 ± 0.09 cm2to 0.54 ± 0.10 cm2). Accordingly, 30 (43%) patients with severe paradoxical LG-SAS were reclassified as having moderate AS. Similar results were obtained when considering 3D-echo for direct planimetry of the LVOT in a subset of 75 patients.
  
  
  CONCLUSIONS
  Our results confirm that the LVOT is elliptical in shape and that taking this parameter into account in the calculation of the AVA results in reclassification of 43% of patients with severe paradoxical LG-AS into moderate AS.
authors.affiliation: Pôle de Recherche Cardiovasculaire, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium.|Division of Cardiology, Cliniques Universitaires Saint-Luc, Brussels, Belgium.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Maes
authors.affiliation: Pôle de Recherche Cardiovasculaire, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium.|Division of Cardiology, Cliniques Universitaires Saint-Luc, Brussels, Belgium.
authors.forename: Sophie
authors.initials: S
authors.lastname: Pierard
authors.affiliation: Pôle de Recherche Cardiovasculaire, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium.|Division of Cardiology, Cliniques Universitaires Saint-Luc, Brussels, Belgium.
authors.forename: Christophe
authors.initials: C
authors.lastname: de Meester
authors.affiliation: Pôle de Recherche Cardiovasculaire, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium.|Division of Cardiology, Cliniques Universitaires Saint-Luc, Brussels, Belgium.
authors.forename: Jamila
authors.initials: J
authors.lastname: Boulif
authors.affiliation: Pôle de Recherche Cardiovasculaire, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium.|Division of Cardiology, Cliniques Universitaires Saint-Luc, Brussels, Belgium.
authors.forename: Mihaela
authors.initials: M
authors.lastname: Amzulescu
authors.affiliation: Pôle de Recherche Cardiovasculaire, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium.|Division of Cardiology, Cliniques Universitaires Saint-Luc, Brussels, Belgium.
authors.forename: David
authors.initials: D
authors.lastname: Vancraeynest
authors.affiliation: Pôle de Recherche Cardiovasculaire, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium.|Division of Cardiology, Cliniques Universitaires Saint-Luc, Brussels, Belgium.
authors.forename: Anne-Catherine
authors.initials: AC
authors.lastname: Pouleur
authors.affiliation: Pôle de Recherche Cardiovasculaire, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium.|Division of Cardiology, Cliniques Universitaires Saint-Luc, Brussels, Belgium.
authors.forename: Agnès
authors.initials: A
authors.lastname: Pasquet
authors.affiliation: Pôle de Recherche Cardiovasculaire, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium.|Division of Cardiology, Cliniques Universitaires Saint-Luc, Brussels, Belgium.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Gerber
authors.affiliation: Pôle de Recherche Cardiovasculaire, Institut de Recherche Expérimentale et Clinique, Université Catholique de Louvain, Brussels, Belgium. jean-louis.vanoverschelde@uclouvain.be.|Division of Cardiology, Cliniques Universitaires Saint-Luc, Brussels, Belgium. jean-louis.vanoverschelde@uclouvain.be.
authors.forename: Jean-Louis
authors.identifier: http://orcid.org/0000-0002-8133-8913
authors.initials: JL
authors.lastname: Vanoverschelde
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015150:Echocardiography, Doppler; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012042:Registries; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013318:Stroke Volume; D016277:Ventricular Function, Left
keywords: Aortic stenosis; Gradient; Left ventricular outflow tract