title: Quantitative analysis of mitral valve morphology in mitral valve prolapse with real-time 3-dimensional echocardiography: importance of annular saddle shape in the pathogenesis of mitral regurgitation.
abstract: BACKGROUND
  Few data exist on the relation of the 3-dimensional morphology of mitral valve and degree of mitral regurgitation (MR) in mitral valve prolapse.
  
  
  RESULTS
  Real-time 3-dimensional transesophageal echocardiography of the mitral valve was acquired in 112 subjects, including 36 patients with mitral valve prolapse and significant MR (≥3+; MR+ group), 32 patients with mitral valve prolapse but no or mild MR (≤2+; MR- group), 12 patients with significant MR resulting from nonprolapse pathologies (nonprolapse group), and 32 control subjects. The 3-dimensional geometry of mitral valve apparatus was measured with dedicated quantification software. Compared with the normal and MR- groups, the MR+ group had more dilated mitral annulus (P<0.0001), a reduced annular height to commissural width ratio (AHCWR) (P<0.0001) indicating flattening of annular saddle shape, redundant leaflet surfaces (P<0.0001), greater leaflet billow volume (P<0.0001) and billow height (P<0.0001), longer lengths from papillary muscles to coaptation (P<0.0001), and more frequent chordal rupture (P<0.0001). Prevalence of chordal rupture increased progressively with annulus flattening (7% versus 24% versus 42% for AHCWR >20%, 15%-20%, and <15%, respectively; P=0.004). Leaflet billow volume increased exponentially with decreasing AHCWR in patients without chordal rupture (r(2)=0.66, P<0.0001). MR severity correlated strongly with leaflet billow volume (r(2)=0.74, P<0.0001) and inversely with AHCWR (r(2)=0.44, P<0.0001). In contrast, annulus dilatation but not flattening occurred in nonprolapse MR patients. An AHCWR <15% (odds ratio=7.1; P=0.0004) was strongly associated with significant MR in mitral valve prolapse.
  
  
  CONCLUSIONS
  Flattening of the annular saddle shape is associated with progressive leaflet billowing and increased frequencies of chordal rupture and may be important in the pathogenesis of MR in mitral valve prolapse.
authors.affiliation: Li Ka Shing Institute of Health Sciences, Prince of Wales Hospital, Chinese University of Hong Kong, Hong Kong SAR.
authors.forename: Alex Pui-Wai
authors.initials: AP
authors.lastname: Lee
authors.forename: Ming C
authors.initials: MC
authors.lastname: Hsiung
authors.forename: Ivan S
authors.initials: IS
authors.lastname: Salgo
authors.forename: Fang
authors.initials: F
authors.lastname: Fang
authors.forename: Jun-Min
authors.initials: JM
authors.lastname: Xie
authors.forename: Yan-Chao
authors.initials: YC
authors.lastname: Zhang
authors.forename: Qing-Shan
authors.initials: QS
authors.lastname: Lin
authors.forename: Jen-Li
authors.initials: JL
authors.lastname: Looi
authors.forename: Song
authors.initials: S
authors.lastname: Wan
authors.forename: Randolph H L
authors.initials: RH
authors.lastname: Wong
authors.forename: Malcolm J
authors.initials: MJ
authors.lastname: Underwood
authors.forename: Jing-Ping
authors.initials: JP
authors.lastname: Sun
authors.forename: Wei-Hsian
authors.initials: WH
authors.lastname: Yin
authors.forename: Jeng
authors.initials: J
authors.lastname: Wei
authors.forename: Shen-Kou
authors.initials: SK
authors.lastname: Tsai
authors.forename: Cheuk-Man
authors.initials: CM
authors.lastname: Yu
mesh_terms: D000328:Adult; D000368:Aged; D002815:Chordae Tendineae / Q000000981:diagnostic imaging / Q000473:pathology; D018450:Disease Progression; D019560:Echocardiography, Three-Dimensional / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging* / Q000473:pathology; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging* / Q000473:pathology; D008945:Mitral Valve Prolapse / Q000000981:diagnostic imaging* / Q000473:pathology; D015588:Observer Variation; D011237:Predictive Value of Tests; D012422:Rupture, Spontaneous / Q000000981:diagnostic imaging / Q000473:pathology; D012720:Severity of Illness Index