Three-dimensional transoesophageal echocardiography is crucial for valid assessment of mitral valve leaflet morphology in severe mitral regurgitation prior to interventional repair

Echocardiographic Variables Associated with Transvalvular Gradient After a Transcatheter Edge-To-Edge Mitral Valve Repair

BACKGROUND

Transcatheter edge-to-edge mitral valve repair may lead to a reduction in mitral valve area (MVA) and elevated mean transmitral gradient (TMG). The objectives of this study were to assess the value of baseline MVA by different imaging methods and to explore the associations between MVA indexed to body surface area or left ventricular forward stroke volume and postprocedural TMG.

METHODS

Preprocedural echocardiographic images from 76 consecutive patients were retrospectively reviewed. MVA planimetry from two-dimensional (2D) transthoracic echocardiography (MVA_TTE), 2D transesophageal echocardiography in the transgastric view (MVA_{2D TEE}), and three-dimensional (3D) transesophageal echocardiography (MVA_3D) were measured. Postprocedural TMGs were assessed at 1 to 3 months and all-cause mortality at 1 year.

RESULTS

Postprocedural mean TMG > 5 mm Hg was associated with a 3.42-fold (95% confidence interval [CI], 1.08-10.87; P = .04) increased risk for 1-year all-cause mortality. Patients with postprocedural TMG > 5 mm Hg (25% [19 of 76]) had significantly smaller preprocedural MVA_3D (3.9 ± 0.8 vs 5.2 ± 1.3 cm², P < .01) and MVA_TTE (4.9 ± 1.1 vs 5.8 ± 1.5 cm², P = .01) compared with patients without elevated TMG. No significant difference was found for MVA_{2D TEE} (P = .20). The best threshold values for MVA_3D and MVA_TTE to be associated with postprocedural TMG > 5 mm Hg were, respectively, 3.9 cm² (area under the curve [AUC] = 0.80; 95% CI, 0.66-0.94; sensitivity 62%, specificity 87%) and 4.6 cm² (AUC = 0.68; 95% CI, 0.54-0.82; sensitivity 53%, specificity 80%). MVA_3D indexed to body surface area and to stroke volume showed overall the best associations with postprocedural mean TMG > 5 mm Hg, with optimal thresholds, respectively, of 2.5 cm²/m² (AUC = 0.88; 95% CI, 0.77-0.98; sensitivity 92%, specificity 74%) and 95 cm²/L (AUC = 0.87; 95% CI, 0.77-0.97; sensitivity 85%, specificity 82%).

CONCLUSIONS

Elevated TMG following transcatheter edge-to-edge mitral valve repair was associated with increased mortality. The present results indicate that MVA_3D, MVA_3D indexed to body surface area, and MVA_3D indexed to stroke volume may be considered potential predictors of postprocedural TMG > 5 mm Hg and could help optimize patient selection, while the use of 2D methods for valve area were poorly associated with TMG.