title: Quantitative multi-slice computed tomography assessment of the mitral valvular complex for transcatheter mitral valve interventions part 2: geometrical measurements in patients with functional mitral regurgitation.
abstract: OBJECTIVE
  Transcatheter mitral valve replacement (TMVR) is an emerging technology with the potential to treat patients with mitral regurgitation at excessive risk for mitral valve surgery. Geometrical measurements of the mitral valvular complex may have implications for the design of TMVR devices and for patient selection. This study sought to quantify the dynamic geometry of the mitral valvular complex in patients with significant functional mitral regurgitation (FMR) using multi-slice computed tomography (MSCT).
  
  
  RESULTS
  MSCT images were acquired in 32 patients with symptomatic, significant FMR. Two independent observers analysed image sets using a dedicated software package and a standard measurement methodology. In patients with FMR, the mean mitral annulus intercommissural and aorto-mural diameters were, respectively, 41.5±5.2 mm and 38.7±5.9 mm in systole, and were 41.5±4.4 mm and 40.0±4.7 mm in diastole. In patients without MR, the diameters were, respectively, 33.6±5.1 mm and 28.8±8.0 mm in systole, and 36.2±4.5 mm and 31.6±7.9 mm in diastole. The obstacle-free zone below the mitral annulus averaged more than 20.0 mm and varied by less than 1 mm between systole and diastole, which is not statistically significant. The aorto-mitral angle was 129.7±10.5° in systole and 131.0±9.4° in diastole.
  
  
  CONCLUSIONS
  The mitral annulus is larger in dimension, more circular, and less dynamic in patients with FMR. The obstacle-free zone below the mitral annulus is relatively constant during the cardiac cycle. Measurements of the mitral valvular apparatus vary considerably between patients, which suggests that tridimensional imaging will play an important role in the sizing of TMVR devices.
authors.affiliation: Department of Medicine, Division of Cardiology, McGill University Health Centre, Montreal, Quebec, Canada.
authors.forename: Pascal
authors.initials: P
authors.lastname: Thériault-Lauzier
authors.forename: Magdalena
authors.initials: M
authors.lastname: Dorfmeister
authors.forename: Darren
authors.initials: D
authors.lastname: Mylotte
authors.forename: Ali
authors.initials: A
authors.lastname: Andalib
authors.forename: Marco
authors.initials: M
authors.lastname: Spaziano
authors.forename: Philipp
authors.initials: P
authors.lastname: Blanke
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Martucci
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Lange
authors.forename: Jonathon
authors.initials: J
authors.lastname: Leipsic
authors.forename: Luc
authors.initials: L
authors.lastname: Bilodeau
authors.forename: Nicolo
authors.initials: N
authors.lastname: Piazza
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006328:Cardiac Catheterization / Q000379:methods; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging*; D019918:Heart Valve Prosthesis Implantation / Q000379:methods; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging*; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging*; D061330:Multidetector Computed Tomography; D015588:Observer Variation; D010210:Papillary Muscles / Q000000981:diagnostic imaging*; D018579:Patient Selection; D011474:Prosthesis Design; D012189:Retrospective Studies; D012720:Severity of Illness Index