title: Gross and histological features of excised portions of posterior mitral leaflet in patients having operative repair of mitral valve prolapse and comments on the concept of missing (= ruptured) chordae tendineae.
abstract: OBJECTIVE
  The aim of the study is to describe gross and histological features of operatively excised portions of mitral valves in patients with mitral valve prolapse (MVP).
  
  
  BACKGROUND
  Although numerous articles on MVP (myxomatous or myxoid degeneration, billowing or floppy mitral valve) have appeared, 2 virtually constant histological features have been underemphasized or overlooked: 1) the presence of superimposed fibrous tissue on both surfaces of the leaflets and surrounding many chordae tendineae; and 2) the absence of many chordae tendineae on the ventricular surfaces of the leaflets as the result of their being hidden (i.e., covered up) by the superimposed fibrous tissue.
  
  
  METHODS
  We examined operatively excised portions of prolapsed posterior mitral leaflets in 37 patients having operative repair.
  
  
  RESULTS
  Histological study of elastic-tissue stained sections disclosed that the leaflet thickening was primarily due to the superimposed fibrous tissue. All leaflets had variable increases in the spongiosa element within the leaflet itself with some disruption and/or loss of the fibrosa element and occasionally complete separation of it from the spongiosa element. Both the leaflet and chordae were separated from the superimposed fibrous tissue by their black-staining elastic membranes.
  
  
  CONCLUSIONS
  These findings demonstrate that the posterior leaflet thickening in MVP is mainly due to the superimposed fibrous tissue rather than to an increased volume of the spongiosa element of the leaflet itself. The superimposed fibrous tissue on both leaflet and chordae is likely the result of subsequent abnormal contact of the leaflets and chordae with one another. Chordal rupture (i.e., missing chordae) occurred in all 37 patients, but finding individual ruptured chords was rare.
authors: Baylor Heart and Vascular Institute, Baylor University Medical Center, Dallas, Texas; Department of Internal Medicine (Division of Cardiology), Baylor University Medical Center, Dallas, Texas; Department of Pathology, Baylor University Medical Center, Dallas, Texas. Electronic address: wc.roberts@baylorhealth.edu.
authors: William C
authors: WC
authors: Roberts
authors: Baylor Heart and Vascular Institute, Baylor University Medical Center, Dallas, Texas.
authors: Travis J
authors: TJ
authors: Vowels
authors: Baylor Heart and Vascular Institute, Baylor University Medical Center, Dallas, Texas.
authors: Jong M
authors: JM
authors: Ko
authors: Department of Cardiothoracic Surgery, Baylor University Medical Center, Dallas, Texas.
authors: Robert F
authors: RF
authors: Hebeler
mesh_terms: D000328:Adult; D000368:Aged; D002815:Chordae Tendineae; D005260:Female; D006341:Heart Rupture / Q000473:pathology*; D019918:Heart Valve Prosthesis Implantation; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000473:pathology* / Q000601:surgery; D008945:Mitral Valve Prolapse / Q000473:pathology / Q000601:surgery*
keywords: mitral regurgitation; mitral valve prolapse; mitral valve repair