Abstract 13429: Echocardiographic Predictors of Mitral Transvalvular Gradients After Mitraclip Insertion

Abstract

Introduction: The MitraClip procedure is a non-surgical alternative for patients with severe mitral regurgitation and high surgical risk. However, the MitraClip may lead to a reduction in the mitral valve orifice area (MVOA) and elevated transmitral mean gradients (TMG). The objectives of this study are to assess the value of baseline MVOA by different imaging methods and explore the value of MVOA indexed for left ventricular (LV) forward stroke volume (SV) to predict postprocedural TMG. Methods: Preprocedural echo images were retrospectively reviewed in 76 consecutive patients. MVOA from 2D transthoracic (MVOA TTE ), 2D transgastric (MVOA TG ) and 3D transesophageal (MVOA 3D ) echocardiography were measured and then indexed by the SV measured by Doppler in the LV outflow tract (MVOA/SV) . Postprocedural TMG was measured at one month and survival rate at one year. Results: Patients with postprocedural TMG >5 mmHg (18/76, 24%) had significantly smaller preprocedural MVOA 3D (3.9±0.9 vs 5.2±1.3 cm 2 , p<0.01) and MVOA TTE (4.9±1.1 vs 5.9±1.5 cm 2 , p=0.02). No significant difference was found for MVOA TG (5.5±1.4 vs 5.9±1.4 cm 2 , p=0.2). Best threshold values for MVOA 3D and MVOA TTE to predict postprocedural TMG >5 mmHg were respectively 3.9 cm 2 (AUC=0.80, IC95%: 0.67-0.94, p<0.01; sensitivity (Se) 62%, specificity (Sp) 87%) and 4,6 cm 2 (AUC=0.69, IC95%: 0.54-0.83, p=0.02; Se 50%, Sp 84%). MVOA/SV from each echocardiographic modality were smaller in patients with postprocedural TMG >5 mmHg (3D: 80 [62-95] vs 113 [99-129] cm 2 /L; TTE: 92 [81-105] vs 130 [100-166] cm 2 /L; TG: 104 [83-123] vs 135 [104-166] cm 2 /L; p<0.01 for all). MVOA/SV 3D was overall the best predictor of postprocedural TMG >5 mmHg, with an optimal threshold of 96 cm 2 /L (AUC=0.86, IC95%: 0.76-0.97, p<0.001; Se 84%, Sp 81%). Patients with MVOA 3D <3.9 cm 2 and MVOA/SV 3D <96 cm 2 /L tend to be at higher risk for mortality at one-year follow-up (69% vs 84%, p=0.14 and 67% vs 87%, p=0.11 respectively). Conclusion: Unlike preprocedural MVOAs assessed by 3D echocardiography, preprocedural MVOAs measured by 2D echocardiographic modalities were poor predictors of high TMG after MitraClip. Preprocedural MVOA 3D <3.9 cm 2 and MVOA/SV 3D <96 cm 2 /L were found to be the best cut-off values to predict postprocedural TMG >5 mmHg.