Mitral Valve Geometry in Paediatric Rheumatic Mitral Regurgitation

Rheumatic mitral valve disease is associated with valvulitis and valvular regurgitation; however, the effect of the rheumatic process on the mitral valve geometry and function is not well understood. To assess mitral valve annulus remodelling in rheumatic mitral valve disease, 16 subjects aged 6–15 years with rheumatic mitral valve regurgitation [MR] [6 mild or moderate (Group 1), 10 severe (Group 2)] and 7 age- and body size-matched normal controls with adequate trans-thoracic echocardiograms were recruited. None of the patients had undergone surgical intervention and none had more than mild aortic regurgitation. None of the patients had mitral stenosis. 3D mitral valve geometry was assessed using a Tomtec system. The non-planar angle was increased in all subjects during early (control 147° ± 10, Group 1 168° ± 9, Group 2 166° ± 10; p < 0.05) and late systole (control 149° ± 12, Group 1 162° ± 10, Group 2 164° ± 6; p < 0.05), indicating loss of saddle shape. 2D annular area increased in Group 2 (control 397 ± 48 mm2/m2 vs Group 2 739 ± 207, p < 0.05) with no significant change in annular perimeter indicating leaflet effacement. Mitral valve area correlated with left ventricular size (p < 0.001, r2 = 0.74). There was no significant change in valve area and perimeter between early and late systole. Remodelling of the mitral valve apparatus in childhood rheumatic heart disease results in abnormal annular geometry. The mitral valve loses its saddle shape regardless of the severity of MR. This may be a consequence of inflammation on the fibrous trigones and surrounding annulus. In contrast, annular area enlargement occurs as a result of leaflet effacement and relates to MR severity and LV size.