title: Subvalvular repair: the key to repairing ischemic mitral regurgitation?
abstract: BACKGROUND
  Residual or recurrent mitral regurgitation frequently occurs after mitral ring annuloplasty repair for ischemic mitral regurgitation (IMR), because annuloplasty primarily addresses annular dilatation. We describe a subvalvular repair technique addressing posterior papillary muscle (PPM) displacement.
  
  
  RESULTS
  Ten sheep had radiopaque markers placed on the left ventricle (LV) and mitral apparatus. A suture was anchored at the right fibrous trigone, passed through the PPM tip and LV wall, and exteriorized through a tourniquet (STRING-1). A second suture was anchored transmurally in the high septum (anterobasal LV wall) and passed through the PPM and LV wall (STRING-2). Reversible posterolateral ischemia was induced by temporarily occluding the proximal circumflex artery. Under open chest conditions, 3D marker coordinates were obtained with biplane videofluoroscopy at baseline and during acute ischemia before and after tightening of each STRING using transesophageal echocardiography to grade IMR. IMR decreased (mean+/-SEM, 2.0+/-0.1 to 1.2+/-0.1; P<0.05) when STRING-1 was tightened, did not change after tightening STRING-2 (2.3+/-0.1 to 2.3+/-0.1), and decreased after tightening both sutures (STRING-1+2, 2.3+/-0.2 to 1.3+/-0.2; P<0.05). STRING-1 and STRING-1+2 (STRING-1, 1.7+/-0.4 mm; STRING-2, 0.7+/-0.5 mm; STRING-1+2, 1.5+/-0.3 mm; P<0.05) resulted in significant PPM basal repositioning. Tightening of any STRING sutures did not affect anterior mitral leaflet excursion.
  
  
  CONCLUSIONS
  Basal repositioning of the PPM with STRING-1 reduced acute IMR without concomitant annular reduction. This technique may be a useful adjunct if residual IMR is likely after undersized ring annuloplasty.
authors.affiliation: Department of Cardiothoracic Surgery, Stanford University School of Medicine, 300 Pasteur Dr, Stanford, CA 94305, USA.
authors.forename: Frank
authors.initials: F
authors.lastname: Langer
authors.forename: Filiberto
authors.initials: F
authors.lastname: Rodriguez
authors.forename: Saskia
authors.initials: S
authors.lastname: Ortiz
authors.forename: Allen
authors.initials: A
authors.lastname: Cheng
authors.forename: Tom C
authors.initials: TC
authors.lastname: Nguyen
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; D006328:Cardiac Catheterization; D004195:Disease Models, Animal; D005471:Fluoroscopy; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D008944:Mitral Valve Insufficiency / Q000209:etiology / Q000473:pathology / Q000601:surgery*; D009038:Motion; D017202:Myocardial Ischemia / Q000150:complications*; D010210:Papillary Muscles / Q000000981:diagnostic imaging / Q000473:pathology; D012756:Sheep; D013536:Suture Techniques; D014741:Video Recording