title: Influence of chronic tethering of the mitral valve on mitral leaflet size and coaptation in functional mitral regurgitation.
abstract: OBJECTIVE
  The purposes of this study were to examine whether tethering of the mitral leaflets affects coaptation in patients with functional mitral regurgitation (FMR) and to assess the interaction between the mitral coaptation and mitral regurgitation severity.
  
  
  BACKGROUND
  Functional mitral regurgitation causes restriction of leaflet closure as a result of enhanced tethering of the mitral leaflets and papillary muscle (PM) displacement.
  
  
  METHODS
  Three-dimensional transesophageal echocardiography was performed in 44 patients with FMR related to the bilateral PM displacement and in 56 controls. The distance between the tip of the anterior or posterior PM and the intervalvular fibrosa were measured as the lateral or medial tethering length (TL) in midsystole. To evaluate the degree of coaptation, coaptation length (CL) at medial, middle, and lateral sites of mitral valve and an estimate of coaptation area (CA) were measured.
  
  
  RESULTS
  The FMR group showed the significantly decreased CA (1.3 ± 0.4 cm(2) vs. 1.6 ± 0.4 cm(2), p = 0.005) and CL (medial 3.2 ± 0.9 mm vs. 4.8 ± 0.6 mm, middle 3.8 ± 1.3 mm vs. 5.8 ± 0.7 mm, lateral 3.3 ± 0.9 mm vs. 4.8 ± 0.6 mm; all p < 0.0001) compared with the controls. Each CL correlated negatively and significantly with both medial and lateral TL (all p < 0.0001). Annular area (p = 0.004) was significantly smaller and leaflet-to-annular area ratio (p < 0.0001) was significantly larger in patients with nonsignificant FMR than in the patients with significant (moderate to severe) FMR. Significant correlations were found between effective regurgitant orifice area and CA or each CL (all p < 0.0001).
  
  
  CONCLUSIONS
  Coaptation decreased significantly in patients with FMR. The CL at each region was related to PM displacement and the indexes of coaptation were associated with mitral regurgitation severity.
authors.affiliation: Department of Cardiology, Kawasaki Medical School, Kurashiki, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Saito
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Okura
authors.forename: Nozomi
authors.initials: N
authors.lastname: Watanabe
authors.forename: Kikuko
authors.initials: K
authors.lastname: Obase
authors.forename: Tomoko
authors.initials: T
authors.lastname: Tamada
authors.forename: Terumasa
authors.initials: T
authors.lastname: Koyama
authors.forename: Akihiro
authors.initials: A
authors.lastname: Hayashida
authors.forename: Yoji
authors.initials: Y
authors.lastname: Neishi
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kawamoto
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Yoshida
mesh_terms: D000368:Aged; D019560:Echocardiography, Three-Dimensional; D017548:Echocardiography, Transesophageal / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008943:Mitral Valve / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008944:Mitral Valve Insufficiency / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D010210:Papillary Muscles / Q000000981:diagnostic imaging / Q000503:physiopathology; D012720:Severity of Illness Index; D016277:Ventricular Function, Left / Q000502:physiology*; D020257:Ventricular Remodeling