Real-Time Left Ventricular Pressure: Volume Loops during Percutaneous Mitral Valve Repair with the MitraClip System
Background—Percutaneous mitral valve repair (MVR) with the MitraClipTM device has emerged as an alternative to surgery for treating severe mitral regurgitation (MR). However, its effects on left ventricular (LV) loading conditions and contractility have not been investigated yet.
Methods and Results—Pressure-volume (PV) loops were recorded throughout the MitraClipTM procedure using conductance catheter in 33 patients (mean age, 78±10 years) with functional (45%), degenerative (48%), or mixed (6%) MR. Percutaneous MVR increased end-systolic wall stress (WSES) (from (median (IQR)) 184 (140-200) to 209 (176-232) mmHg, P=0.001) and decreased end-diastolic wall stress (WSED) (from 48 (28-58) to 34 (21-46) mmHg, P=0.005), while end-systolic pressure-volume relationship (ESPVR) was not significantly affected. Conversely, CI increased (from 2.6 (2.2-3.0) to 3.2 (2.6-3.8) L/min/m2, P<0.001) and mean PCWP decreased (from 15 (12-20) to 12 (10-13) mmHg, P<0.001). While changes in ΔWSES (ΔWSES) were not correlated with ΔCI, ΔWSED correlated significantly with ΔmPCWP (r=0.63, P<0.001). Total mechanical energy assessed by the pressure-volume area (PVA) remained unchanged resulting in a more favourable forward output (CI) to mechanical energy (PVA) ratio after MVR. On follow-up (153±94 days), NYHA 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 (95-191) to 127 (82-202) mL, P=0.036).
Conclusions—Percutaneous MVR improves hemodynamic profiles and induces reverse LV remodeling by reducing LV preload while preserving contractility. In nonsurgical candidates with compromised LV function, MitraClipTMtherapy could be considered as an alternative to surgical MVR.
- conductance catheter
- mitral regurgitation
- percutaneous mitral valve repair
- pressure-volume relationship
- Received August 4, 2012.
- Revision received January 8, 2013.
- Accepted January 10, 2013.
- Copyright © 2013, Circulation