Echocardiographic evaluation of congenital mitral valve anomalies in children

Abstract

Congenital mitral valve anomalies were diagnosed in 65 children, whose ages ranged from newborn to 18 years, using 2-dimensional, color, pulsed-, and continuous-wave Doppler ultrasound. Data were collected over 7.5 years from 13,400 new studies. Data in these patients were compared with those obtained by cardiac catheterization, cardiac surgery, and autopsy. We detected 4 different lesions: (1) congenital mitral stenosis with 2 papillary muscles (n = 24); (2) parachute mitral valve, with a single papillary muscle (n = 24); (3) isolated cleft in the mitral valve (n = 10); and (4) double-orifice mitral valve (n = 7). A supravalvar mitral ring was detected in 21 patients with mitral stenosis; however, it never occurred as an isolated lesion and was invariably associated with some other left ventricular inflow or outflow obstruction. The supravalvar ring was associated with a parachute deformity of the mitral valve in 17 patients; in only 4 was this abnormality associated with mitral stenosis with 2 papillary muscles. In patients with congenital mitral stenosis, the peak and mean transmitral Doppler velocities were increased significantly compared with those in controls (peak velocity 1.53 ± 0.74 vs 0.86 ± 0.25 m/s, respectively, p < 0.01; mean velocity 1.13 ± 0.61 vs 0.58 ± 0.11 m/s, respectively, p < 0.01). The correlation between mean transmitral pressure gradient obtained by Doppler and cardiac catheterization was fair (r = 0.75). However, the correlation between the mitral valve areas calculated by the Doppler pressure half-time method and by the Gorlin formula was poor (r = 0.57). Eleven of the 24 patients with parachute mitral valve deformities had Doppler evidence of an increased transmitral gradient. In children, echocardiography proved superior to cineangiography as a diagnostic modality, and can be relied upon in making management decisions, but Doppler velocities, including pressure halftime, applicable in adults for calculation of mitral valve area are unreliable.