title: Real-time left ventricular pressure-volume loops during percutaneous mitral valve repair with the MitraClip system.
abstract: BACKGROUND
  Percutaneous mitral valve repair with the MitraClip device has emerged as an alternative to surgery for treating severe mitral regurgitation. However, its effects on left ventricular loading conditions and contractility have not been investigated yet.
  
  
  RESULTS
  Pressure-volume loops were recorded throughout the MitraClip procedure using conductance catheter in 33 patients (mean age, 78±10 years) with functional (45%), degenerative (48%), or mixed (6%) mitral regurgitation. Percutaneous mitral valve repair increased end-systolic wall stress (WSES; from [median] 184 mm Hg [interquartile range (IQR), 140-200 mm Hg] to 209 mm Hg [IQR, 176-232 mm Hg]; P=0.001) and decreased end-diastolic WS (WSED; from 48 mm Hg [IQR, 28-58 mm Hg] to 34 mm Hg [IQR, 21-46 mm Hg]; P=0.005), whereas the end-systolic pressure-volume relationship was not significantly affected. Conversely, cardiac index increased (from 2.6 L·min(-1)·m(-2) [IQR, 2.2-3.0 L·min(-1)·m(-2)] to 3.2 L·min(-1)·m(-2) [IQR, 2.6-3.8 L·min(-1)·m(-2)]; P<0.001) and mean pulmonary capillary wedge pressure decreased (from 15 mm Hg [IQR, 12-20 mm Hg] to 12 mm Hg [IQR, 10-13 mm Hg]; P<0.001). Although changes in WSES were not correlated with changes in cardiac index, changes in WSED correlated significantly with changes in mean pulmonary capillary wedge pressure (r=0.63, P<0.001). Total mechanical energy assessed by the pressure-volume area remained unchanged, resulting in a more favorable index of forward output (cardiac index) to mechanical energy (pressure-volume area) after mitral valve repair. On follow-up (153±94 days), New York Heart Association functional class was reduced from 2.9±0.6 to 1.9±0.5 (P<0.001) at 3 months, and echocardiographic follow-up documented a stepwise reduction in end-diastolic volume (from 147 mL [IQR, 95-191 mL] to 127 mL [IQR, 82-202 mL]; P=0.036).
  
  
  CONCLUSIONS
  Percutaneous mitral valve repair improves hemodynamic profiles and induces reverse left ventricular remodeling by reducing left ventricular preload while preserving contractility. In nonsurgical candidates with compromised left ventricular function, MitraClip therapy could be considered an alternative to surgical mitral valve repair.
authors: Andreas Grüntzig Cardiac Catheterization Laboratories, University Hospital Zurich, Zurich, Switzerland. oliver.gaemperli@usz.ch
authors: Oliver
authors: O
authors: Gaemperli
authors: Patric
authors: P
authors: Biaggi
authors: Remo
authors: R
authors: Gugelmann
authors: Martin
authors: M
authors: Osranek
authors: Jan J
authors: JJ
authors: Schreuder
authors: Ines
authors: I
authors: Bühler
authors: Daniel
authors: D
authors: Sürder
authors: Thomas F
authors: TF
authors: Lüscher
authors: Christian
authors: C
authors: Felix
authors: Dominique
authors: D
authors: Bettex
authors: Jürg
authors: J
authors: Grünenfelder
authors: Roberto
authors: R
authors: Corti
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003199:Computer Systems; D005260:Female; D005500:Follow-Up Studies; D019918:Heart Valve Prosthesis Implantation / Q000379:methods*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008944:Mitral Valve Insufficiency / Q000503:physiopathology* / Q000601:surgery*; D012042:Registries; D016277:Ventricular Function, Left / Q000502:physiology*; D017725:Ventricular Pressure / Q000502:physiology*