Doppler echocardiographic evaluation of tilting-disc prosthetic heart valves in children

Abstract

To determine the Doppler characteristics of tilting-disc prosthetic heart valves in children, 22 children with mitral prostheses were studied 8 ± 2 months after surgery, and 10 children with aortic prostheses were studied 37 ± 26 months after surgery. All valves were thought to be functioning normally by clinical examination. Valve competence was interrogated and peak and mean velocities were measured by standard pulsed wave, continuous wave and color Doppler techniques. Prosthetic valve area was calculated and compared to the known valve area. Mild prosthetic valve regurgitation was present in 8 of 22 mitral and 7 of 10 aortic prostheses. For mitral prostheses, peak velocity was 192 ± 41 cm/s, mean velocity was 118 ± 37 cm/s and mean gradient was 7 ± 4 mm Hg. For aortic prostheses, peak velocity was 287 ± 88 cm/s, mean velocity was 197 ± 59 cm/s, peak gradient was 36 ± 21 mm Hg and mean gradient was 19 ± 11 mm Hg. Prosthetic mitral valve area, calculated by the pressure half-time and modified Gorlin methods, correlated well with the known valve area (r = 0.89, standard error of the estimate = 0.29 and r = 0.95, standard error of the estimate = 0.21, respectively). Prosthetic aortic valve area, calculated by the modified Gorlin method, correlated well with the known valve area (r = 0.89, standard error of the estimate = 0.18). Residual valvular abnormalities are common after prosthetic valve insertion in children. Doppler estimates of prosthetic valve area correlate well with the known valve area but have a large standard error of the estimate.