title: Transmural compensation of myocardial deformation to preserve left ventricular ejection performance in chronic aortic regurgitation.
abstract: BACKGROUND
  In patients with chronic aortic regurgitation (AR), systolic wall stress and volume overload affects left ventricular (LV) systolic function and remodeling. The aim of this study was to assess transmural rearrangements of myocardial deformation to preserve LV ejection performances using speckle-tracking echocardiography in patients with chronic AR.
  
  
  METHODS
  Ninety patients with AR were enrolled. On LV short-axis images, total, inner, and outer radial strain and circumferential strain at the inner, mid, and outer layers were calculated. On apical four-chamber images, endocardial longitudinal strain was calculated. End-systolic wall stresses were calculated using previous methods.
  
  
  RESULTS
  AR severities were classified as moderate in 31 patients, severe and preserved LV ejection fraction (LVEF) (≥50%) in 42 patients, and severe and reduced LVEF (<50%) in 17 patients. Longitudinal strain was decreased even in the moderate AR group, despite normal end-systolic wall stress. Inner radial strain progressively decreased with increasing end-systolic wall stress, whereas outer radial strain in the moderate and severe AR and preserved LVEF groups was higher than in the control group. Consequently, total radial strain was preserved even in the severe AR and preserved LVEF groups with increased end-systolic wall stress. Similarly, despite reduced inner circumferential strain, outer circumferential strain was higher in the severe AR and preserved LVEF group than in the control group. All strain parameters were lower in the severe AR and reduced LVEF group with dramatically increased end-systolic wall stress than in other groups.
  
  
  CONCLUSIONS
  Transmural strain analysis revealed that subendocardial dysfunction accompanied by increased wall thickening at the subepicardium may be a compensatory mechanism of wall thickening to preserve LVEF in patients with chronic AR.
authors.affiliation: Department of Clinical Laboratory, Tsukuba University Hospital, Tsukuba, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Iida
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Seo
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ishizu
authors.forename: Hideki
authors.initials: H
authors.lastname: Nakajima
authors.forename: Akiko
authors.initials: A
authors.lastname: Atsumi
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Tomoko
authors.initials: T
authors.lastname: Machino-Ohtsuka
authors.forename: Ryo
authors.initials: R
authors.lastname: Kawamura
authors.forename: Mami
authors.initials: M
authors.lastname: Enomoto
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kawakami
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Aonuma
mesh_terms: D001022:Aortic Valve Insufficiency / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D002908:Chronic Disease; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013314:Stress, Mechanical; D013318:Stroke Volume