title: Cutting second-order chords does not prevent acute ischemic mitral regurgitation.
abstract: BACKGROUND
  Cutting anterior mitral leaflet second-order chordae has been proposed for repair in ischemic mitral regurgitation (IMR). We examined the efficacy of such chordal cutting in preventing acute IMR.
  
  
  RESULTS
  Six sheep underwent radiopaque marker placement (left ventricle, mitral annulus, papillary muscles [PMs], and leaflets). The largest second-order chord from each PM was encircled with exteriorized wire snares. Three-dimensional marker coordinates were obtained with biplane videofluoroscopy before and during acute ischemia (80 seconds of mid-circumflex occlusion). Color Doppler transesophageal echocardiography was used to grade MR on a 0 to 4+ scale. Data were acquired immediately before and after dividing second-order chordae. Slope of the end-diastolic volume-stroke work relationship (PRSW) was calculated to assess systolic function. Chordal cutting increased anterior leaflet inflection angle (155+/-12 versus 162+/-9 degrees; P=0.03), resulting in a flatter leaflet, but did not increase effective leaflet length (1.97+/-0.24 versus 2.08+/-0.23 cm; P=0.15); PRSW decreased (63+/-15 versus 56+/-12 mm Hg; P=0.008). Both before and after chordal cutting, ischemia caused: Septal-lateral annular dilation (P=0.005), posterior PM displacement away from the mid-septal annulus (P=0.06), increased leaflet tenting area (P=0.001), and increased leaflet tenting volume (P=0.002). Before chordal cutting, MR increased significantly during ischemia (0.5+/-0.3 versus 1.7+/-0.4; P<0.001), and IMR increased similarly even after the second-order chords were cut (0.7+/-0.4 versus 1.9+/-0.9; P<0.001).
  
  
  CONCLUSIONS
  Cutting second-order chordae resulted in LV systolic dysfunction and neither prevented nor decreased the severity of acute IMR, septal-lateral annular dilation, leaflet tenting area, or leaflet tenting volume.
authors.affiliation: Department of Cardiothoracic Surgery, Stanford University School of Medicine, Stanford, Calif 94305-5247, USA.
authors.forename: Filiberto
authors.initials: F
authors.lastname: Rodriguez
authors.forename: Frank
authors.initials: F
authors.lastname: Langer
authors.forename: Katherine B
authors.initials: KB
authors.lastname: Harrington
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Tibayan
authors.forename: Mary K
authors.initials: MK
authors.lastname: Zasio
authors.forename: David
authors.initials: D
authors.lastname: Liang
authors.forename: George T
authors.initials: GT
authors.lastname: Daughters
authors.forename: Neil B
authors.initials: NB
authors.lastname: Ingels
authors.forename: D Craig
authors.initials: DC
authors.lastname: Miller
mesh_terms: D000208:Acute Disease; D000818:Animals; D002815:Chordae Tendineae / Q000601:surgery*; D004195:Disease Models, Animal; D018618:Echocardiography, Doppler, Color; D021621:Imaging, Three-Dimensional; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging / Q000209:etiology / Q000517:prevention & control*; D009200:Myocardial Contraction; D017202:Myocardial Ischemia / Q000150:complications*; D011859:Radiography; D012756:Sheep; D017211:Treatment Failure