title: Septal-lateral annular cinching ('SLAC) reduces mitral annular size without perturbing normal annular dynamics.
abstract: OBJECTIVE
  Septal-lateral (S-L) mitral annular diameter reduction is thought to be central to the efficacy of ring annuloplasty in correcting functional mitral regurgitation (MR), but rings perturb mitral annulus (MA) dynamic motion and limit posterior leaflet excursion. The effects of S-L annular cinching ('SLAC'), a novel method for mitral annular reduction, were investigated.
  
  
  METHODS
  Eight adult sheep had multiple radioopaque markers placed on the left ventricle, leaflet edges, and around the MA. The S-L trans-annular suture was anchored to the mid-septal MA and externalized through the mid-lateral MA and left ventricular wall. Animals were studied immediately postoperatively with biplane videofluoroscopy before and after suture cinching to reduce annular size. MA area (MAA) and S-L dimension were calculated throughout the cardiac cycle from the annular marker coordinates. MAA contraction (AMAA) was expressed as percentage decrease from maximum to minimum MAA. Anterior (AML) and posterior (PML) leaflet angular excursion were calculated as the change in angle between each leaflet edge marker and the S-L annular dimension during the cardiac cycle. MA folding was calculated as the change in distance during systole of the mid-septal annular marker from a plane fitted to the lateral MA markers.
  
  
  RESULTS
  SLAC reduced end-diastolic (ED) S-L diameter (21.6+/-2.8 versus 17.1+/-2.6 mm; p = 0.0005) and ED MAA (618+/-126 versus 525+/-114 mm2; p = 0.0004), but did not perturb normal AMAA (15.8+/-4.1 versus 15.1+/-4.8%; p = 0.4), annular flexion (2.0+/-0.7 versus 1.8+/-0.7 mm; p = 0.3) or AML excursion (55+/-7 versus 53+/-7 degrees; p = 0.1). PML excursion was decreased only slightly (52+/-11 versus 44+/-12 degrees; p = 0.002).
  
  
  CONCLUSIONS
  SLAC substantially reduced S-L annular size, but without perturbing normal MA contraction dynamics, MA flexion, or anterior leaflet excursion. This novel surgical method might represent an alternative to mitral annuloplasty for patients with certain types of mitral pathology.
authors.affiliation: Department of Cardiothoracic Surgery, Stanford University School of Medicine, CA 94305-5407, USA.
authors.forename: Tomasz A
authors.initials: TA
authors.lastname: Timek
authors.forename: David T
authors.initials: DT
authors.lastname: Lai
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Tibayan
authors.forename: George T
authors.initials: GT
authors.lastname: Daughters
authors.forename: David
authors.initials: D
authors.lastname: Liang
authors.forename: Paul
authors.initials: P
authors.lastname: Dagum
authors.forename: Neil B
authors.initials: NB
authors.lastname: Ingels
authors.forename: D Craig
authors.initials: DC
authors.lastname: Miller
mesh_terms: D000818:Animals; D006348:Cardiac Surgical Procedures; D003287:Contrast Media; D005471:Fluoroscopy; D006439:Hemodynamics; D007091:Image Processing, Computer-Assisted; D008943:Mitral Valve / Q000000981:diagnostic imaging / Q000601:surgery*; D008944:Mitral Valve Insufficiency / Q000601:surgery*; D009068:Movement; D012756:Sheep; D013536:Suture Techniques
chemical_list: D003287:Contrast Media