title: Characteristics and treatment strategies of mitral regurgitation associated with undifferentiated papillary muscle.
abstract: OBJECTIVE
  In this report we review our experience of operations on mitral regurgitation associated with abnormal papillary muscles/chordae tendineae of the mitral valves and discussed the clinical characteristics, operative findings, and treatment strategies.
  
  
  METHODS
  Undifferentiated papillary muscle was defined as a hypoplastic chordae tendineae with anomalous formation of papillary muscles attached to the mitral valves directly. Consecutive 87 patients undergoing surgery for mitral regurgitation at our institution were reviewed and 6 of them had undifferentiated papillary muscle.
  
  
  RESULTS
  The underlying mechanism of regurgitation was prolapse at the center of the anterior leaflet in 3 cases and tethering, a wide area of myxomatous degeneration, and annular dilatation in one case, respectively. Five patients underwent mitral valve plasty and 1 patient received replacement. Anomalous formation of chordae tendineae was corrected by resection and suture with transplantation at the tip of the leaflet to which abnormal chordae were attached in 2 cases, while resection and suture with chordal shortening was performed in 1 case, and chordal reconstruction using artificial chordae was employed in 2 cases. There was no operative death, and postoperative echocardiography showed no residual regurgitation in any of the cases.
  
  
  CONCLUSIONS
  Mitral regurgitation associated with undifferentiated papillary muscle resulted from prolapse or tethering and impaired flexibility of leaflets. It was possible to successfully treat the patients by mitral valve plasty unless complex congenital cardiac malformation coexisted. Detailed examinations of attached papillary muscle by echocardiography and intraoperative inspection are necessary and surgical techniques should be selected appropriately in each case.
authors.affiliation: Department of Cardiovascular Surgery, Nagasaki University Hospital, Nagasaki, Japan. ichiro-m@nagasaki-u.ac.jp
authors.forename: Ichiro
authors.initials: I
authors.lastname: Matsumaru
authors.forename: Koji
authors.initials: K
authors.lastname: Hashizume
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Ariyoshi
authors.forename: Kenta
authors.initials: K
authors.lastname: Izumi
authors.forename: Daisuke
authors.initials: D
authors.lastname: Onohara
authors.forename: Shun
authors.initials: S
authors.lastname: Nakaji
authors.forename: Mizuki
authors.initials: M
authors.lastname: Sumi
authors.forename: Kiyoyuki
authors.initials: K
authors.lastname: Eishi
authors.forename: Akira
authors.initials: A
authors.lastname: Tsuneto
authors.forename: Tomayoshi
authors.initials: T
authors.lastname: Hayashi
mesh_terms: D000293:Adolescent; D000368:Aged; D002454:Cell Differentiation; D002815:Chordae Tendineae / Q000002:abnormalities / Q000000981:diagnostic imaging / Q000601:surgery*; D005260:Female; D006330:Heart Defects, Congenital / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000002:abnormalities / Q000000981:diagnostic imaging / Q000601:surgery*; D058386:Mitral Valve Annuloplasty; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D008945:Mitral Valve Prolapse / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D010210:Papillary Muscles / Q000002:abnormalities / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome; D014463:Ultrasonography