title: Chordal cutting: a new therapeutic approach for ischemic mitral regurgitation.
abstract: BACKGROUND
  Mitral regurgitation (MR) conveys adverse prognosis in ischemic heart disease. Because such MR is related to increased leaflet tethering by displaced attachments to the papillary muscles (PMs), it is incompletely treated by annular reduction. We therefore addressed the hypothesis that such MR can be reduced by cutting a limited number of critically positioned chordae to the leaflet base that most restrict closure but are not required to prevent prolapse. This was tested in 8 mitral valves: a porcine in vitro pilot with PM displacement and 7 sheep with acute inferobasal infarcts studied in vivo with three-dimensional (3D) echo to quantify MR in relation to 3D valve geometry.
  
  
  RESULTS
  In all 8 valves, PM displacement restricted leaflet closure, with anterior leaflet angulation at the basal chord insertion, and mild-to-moderate MR. Cutting the 2 central basal chordae reversed this without prolapse. In vivo, MR increased from 0.8+/-0.2 to 7.1+/-0.5 mL/beat after infarction and then decreased to 0.9+/-0.1 mL/beat with chordal cutting (P<0.0001); this paralleled changes in the 3D leaflet area required to cover the orifice as dictated by chordal tethering (r(2)=0.76).
  
  
  CONCLUSIONS
  Cutting a minimum number of basal chordae can improve coaptation and reduce ischemic MR. Such an approach also suggests the potential for future minimally invasive implementation.
authors.affiliation: Cardiac Ultrasound Laboratory and Surgical Cardiovascular Laboratory, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: E
authors.initials: E
authors.lastname: Messas
authors.forename: J L
authors.initials: JL
authors.lastname: Guerrero
authors.forename: M D
authors.initials: MD
authors.lastname: Handschumacher
authors.forename: C
authors.initials: C
authors.lastname: Conrad
authors.forename: C M
authors.initials: CM
authors.lastname: Chow
authors.forename: S
authors.initials: S
authors.lastname: Sullivan
authors.forename: A P
authors.initials: AP
authors.lastname: Yoganathan
authors.forename: R A
authors.initials: RA
authors.lastname: Levine
mesh_terms: D000818:Animals; D006348:Cardiac Surgical Procedures / Q000379:methods*; D002815:Chordae Tendineae / Q000601:surgery*; D004195:Disease Models, Animal; D006439:Hemodynamics; D066298:In Vitro Techniques; D008943:Mitral Valve / Q000503:physiopathology / Q000601:surgery; D008944:Mitral Valve Insufficiency / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D017202:Myocardial Ischemia / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D010865:Pilot Projects; D012756:Sheep; D013318:Stroke Volume; D013552:Swine; D016896:Treatment Outcome; D016277:Ventricular Function, Left