title: Characterization of mitral valve anterior leaflet perfusion patterns.
abstract: OBJECTIVE
  Although previous histologic studies have demonstrated the presence of blood vessels in the anterior mitral leaflet (AML) and second-order chordae (SC), little is known of the pattern of leaflet perfusion. Hence, the pattern and source of AML perfusion was investigated in an ovine model.
  
  
  METHODS
  Fluorescein angiograms were obtained in 17 ovine hearts immediately after heparinization and cardioplegic arrest, using non-selective left coronary artery (LCA) and selective left anterior descending (LAD), proximal, mid- and distal left circumflex (LCx) perfusion. Serial photographs using a flash/filter system to optimize fluorescence were obtained through a left atriotomy.
  
  
  RESULTS
  The proximal half of the AML was seen to be richly vascularized. A loop of vessels was consistently observed in the mitral annulus and AML; these vessels ran along the annulus, extended to the sites of SC insertion, and created anastomoses between these insertions. The SC contributed to the AML perfusion and the anastomotic loop. Selective perfusion of the LAD or proximal LCx artery (ligated before the first obtuse marginal artery) did not perfuse the AML (n = 6). Perfusion of the mid- and distal LCx (n = 7) consistently supplied the AML via SC insertion sites and annular branches.
  
  
  CONCLUSIONS
  The ovine AML is perfused by vessels that run through the SC and annulus simultaneously, and then create a communicating arcade in the leaflet. These vessels originate from the mid- and distal portions of the LCx. A loss of perfusion as a result of microvascular disease could have adverse implications. Derangements in the extensive vascular component of the mitral valve could be an important contributing factor to valve disease.
authors.affiliation: Department of Cardiothoracic Surgery, Stanford University School of Medicine, Stanford, CA 94305-5247, USA.
authors.forename: Julia C
authors.initials: JC
authors.lastname: Swanson
authors.forename: Lauren R
authors.initials: LR
authors.lastname: Davis
authors.forename: Koji
authors.initials: K
authors.lastname: Arata
authors.forename: Eleazar P
authors.initials: EP
authors.lastname: Briones
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Bothe
authors.forename: Akinobu
authors.initials: A
authors.lastname: Itoh
authors.forename: Neil B
authors.initials: NB
authors.lastname: Ingels
authors.forename: D Craig
authors.initials: DC
authors.lastname: Miller
mesh_terms: D000818:Animals; D005451:Fluorescein Angiography; D008297:Male; D008943:Mitral Valve / Q000033:anatomy & histology* / Q000502:physiology*; D023421:Models, Animal; D012039:Regional Blood Flow; D012756:Sheep