Analysis of Procedural Effects of Percutaneous Edge-to-Edge Mitral Valve Repair by 2D and 3D Echocardiography

Abstract

Background-Analysis of procedural effects in patients undergoing percutaneous mitral valve repair (PMVR) using the edgeto-edge technique is complex, and common methods to define mitral regurgitation severity based on 2-dimensional (2D) echocardiography are not validated for postprocedural double-orifice mitral valve. This study used 3D transesophageal echocardiography (TEE) to determine the functional and morphological effects of PMVR. Methods and Results-In 39 high-risk surgical patients with moderate to severe functional mitral valve regurgitation, 3D TEE with and without color Doppler as well as 2D transthoracic and TEE was performed before and after PMVR (MitraClip device). Mitral valve regurgitant volume by color Doppler 3D TEE was determined as the product of vena contracta areas defined by direct planimetry and velocity time integral using continuous-wave Doppler. Regurgitant volume was reduced from 84.1±38.3 mL preintervention to 35.6±25.6 mL postintervention. Patients in whom vena contracta area could be reduced >50% had a smaller preprocedural mitral annulus area compared with patients with ≤50% reduction (11.9±3.9 versus 16.1±8.5 cm 2 , respectively; P=0.036) and tended to have a smaller mitral annulus circumference (13.0±2.0 versus 14.8±4.1 cm, respectively; P=0.112). At 6 months follow-up, left atrial and left ventricular end-diastolic volumes were significantly more reduced in patients in whom regurgitant vena contracta area was reduced by >50% compared with those with less reduction (−11.4±5.2 versus −4.8±7.7%; P=0.005, and −11.0±7.2 versus −4.5±9.3%; P=0.028). The maximum diastolic mitral valve area decreased from 6.0±2.0 to 2.9±0.9 cm 2 (P<0.0001). Conclusions-Three

Assessment of Mitral Valve Area During Percutaneous Mitral Valve Repair Using the MitraClip System

“…Our results for MVA 3DQ are similar to those recently published in the only other study that used the same technique for MVA assessment. 16 The 3DQ method tends to overestimate MVA if the orifices resulting from clipping are not calculated separately ( Figure 7). Although we followed this rule for measurement, we cannot exclude that slight overestimation of the MVA occurred because of relatively low spatial resolution of 3D data sets.…”

“…We used the predischarge transmitral gradient as an end point of the study instead of a measured MVA because 3D TTE has insufficient image resolution for the assessment of MVA in most postinterventional patients. We did not use 2D TTE measurements because they tend to overestimate MVA, 16,17 and performing another 3D TEE before discharge was not justifiable. Also, it should be expected that with normalization of the hemoglobin level, the transmitral gradients should slightly decrease over time.…”

“…The mitral valve can be displayed using 3 orthogonally orientated planes. So that MVA is not overestimated, the plane in which the measurement is performed is orientated perpendicularly to the valve leaflets 16,17 After clipping, we adjusted the measurement plane separately for each orifice if necessary. …”

Transcathether Valve Replacement and Valve Repair

“…3,27,28 Studies have shown the feasibility of measuring the 3D vena contracta (narrowest portion of the regurgitant jet) on RT3D echocardiography to assess the severity of regurgitation for native regurgitant valve disease 27,[29][30][31] and after surgical 32 or transcatheter interventions. 33 …”

“…A >50% reduction in regurgitant volume using the product of vena contracta areas defined by direct planimetry of RT3D color Doppler and velocity time integral using continuous-wave Doppler was associated with greater left atrial and ventricular remodeling. 33 Multiple operators have suggested various advanced techniques to aid the leaflet capture of difficult cases with less than ideal coaptation characteristics. These include the following: 96 Although the success rate of the MitraClip (defined as a composite of postimplantation MR of grade ≤2+, without conversion to open cardiac surgery, and without in-hospital mortality) is high (91%), there are complications that can be diagnosed during the procedure by echocardiography including cardiac perforation (with or without tamponade), injury to the mitral leaflets or subvalvular apparatus, and transseptal complications.…”