3D mitral valve remodeling in relation to body size and clinical outcomes in primary mitral regurgitation
R B Sindre, C E Berg-Hansen, L M D Grymyr, A Valeur, N A Marsan, J Hung, S Urheim, D CramariucAbstract
Background
Primary mitral regurgitation (MR) causes chronic remodeling of the left ventricle (LV) and left atrium (LA), and progressive changes in mitral geometry with increasing annulus and leaflet area. Mitral annulus (MA) dilatation is an indirect marker of MR severity and informs surgical planning but is rarely reported sex-specifically.
Purpose
To assess sex differences in 3D mitral valve remodeling in significant primary MR.
Methods
In the prospective 3D Echocardiography and Cardiovascular Prognosis in Mitral Regurgitation (3D-PRIME) study, 143 patients (32% women) with moderate or greater primary MR underwent 3D echocardiographic assessment of MA area, anterior and posterior leaflet area, and MA antero-posterior diameter (MAPd). LV function was assessed by global longitudinal strain (GLS), LA remodeling by maximum volume (LAV) and reservoir strain (LASr). The composite outcome included mitral intervention, heart failure hospitalization or death over 2 years.
Results
MR regurgitant fraction was comparable between sexes, with severe MR found in 52% of patients. However, women had smaller MA area (12.6 vs. 15.2 cm2), MAPd (3.5 vs 3.8 cm), anterior (6.4 vs. 7.5cm2) and posterior leaflet area (7.2 vs 8.6 cm2) (p<0.01). The commonly used threshold of MAPd >4.0 cm identified MA dilatation in 52% of women vs 78% of men (p<0.01). In linear regression analysis, female sex was associated with smaller MA area independent of atrial fibrillation and MR severity and after adjusting for significant relations with age, LASr, LV GLS, LAV, and systolic blood pressure.
Indexing to body surface area (BSA) removed sex differences in MA and leaflet areas; indexing to height corrected diameter differences. Increased MA area/BSA >8.2cm2/m2 (by Youden´s index) was found in 78%/ 85% of women/ men and was associated with higher risk of adverse 2-year clinical events in Kaplan-Meier analysis (Figure).
Conclusion
Proper indexation of mitral valve measures to body size allows earlier identification of significant mitral remodeling in women with primary MR and may impact the timing and planning of mitral valve intervention.Figure