Clinical implications of mitral valve geometric alterations in children with dilated cardiomyopathy

Abstract

We aimed to elucidate the relationship between severity of secondary mitral regurgitation and mitral valve geometry in children with dilated cardiomyopathy. The medical records of 16 children with dilated cardiomyopathy (median age, 1.2 years; range, 0.4-12.3 years) were reviewed. Mitral valve geometry was evaluated by measuring coaptation depth using echocardiographic apical four-chamber views at the initial presentation. Patients were dichotomised according to the mitral regurgitation severity: patients with moderate or severe secondary mitral regurgitation (n=6) and those with mild secondary mitral regurgitation (n=10). A total of 58 healthy children were considered as normal controls, and a regression equation to predict coaptation depth by body surface area was derived: coaptation depth [mm]=4.37+1.34×ln (body surface area [m2]) (residual standard error, 0.49; adjusted R2, 0.68; p<0.0001). Compared with patients with mild secondary mitral regurgitation, those with moderate or severe secondary mitral regurgitation had significantly larger coaptation depth z-scores (6.4±2.3 versus 1.9±1.4, p<0.005), larger mitral annulus diameter z-scores (3.6±2.6 versus 0.9±1.8, p<0.05), higher left ventricular sphericity index (0.89±0.07 versus 0.79±0.06, p<0.005), and greater left ventricular fraction shortening (0.15±0.05 versus 0.09±0.05, p<0.05). In conclusion, geometric alteration in the mitral valve and the left ventricle is associated with the severity of secondary mitral regurgitation in paediatric dilated cardiomyopathy, which would provide a theoretical background to surgical intervention for secondary mitral regurgitation in paediatric populations.

Coaptation Triangle and Golden Proportion in mitral valve anatomy. Does nature play with geometry?

“…The coaptation depth is now considered an important index of leaflet tethering and our measurement of 7.4 mm represents another significant result. In fact, literature normal values range between 4.9 and 9.5 mm, with the majority of authors reporting values between 6 and 8 mm . Only Zhang found slightly lower values, around 4.2 mm …”

“…Knowing the geometrical rules determining natural mitral structure could allow us to identify valves prone to disease when still apparently normal. As an example, let us consider the Coaptation Depth: it is generally accepted to be normal between 6 and 8 mm . In a small mitral valve, with an antero‐posterior diameter of 25 mm, a Coaptation Depth of 6 mm perfectly satisfies the Golden Proportion, while a Coaptation Depth of 8 mm, even if still within normal ranges could probably mean that an initial leaflet tethering has occurred.…”

Echocardiographic predictors of coil vs device closure in patients undergoing percutaneous patent ductus arteriosus closure

“…We hypothesized that the LV dilation and remodeling conferred by left ventricular volume overload may be predictive of the hemodynamic significance of the shunt and consequently the mode of closure. Sphericity index has been previously studied in a cohort of patients with dilated cardiomyopathy, and it was found to correlate significantly with the degree of mitral regurgitation in this group of patients . Although the volume overload conferred by PDA shunt is a known etiological factor of MR, none of the patients enrolled in our study had significant MR.…”

“…Sphericity index has been previously studied in a cohort of patients with dilated cardiomyopathy, and it was found to correlate significantly with the degree of mitral regurgitation in this group of patients. 27 Although the volume overload conferred by PDA shunt is a known etiological factor of MR, none of the patients enrolled in our study had significant MR.…”