Continuous wave Doppler echocardiographic evaluation of St. Jude prosthetic mitral valves in children.
The function of 9 St. Jude prosthetic mitral valves in 8 children was evaluated by continuous wave Doppler (CWD) echocardiography 28 +/- 22 months after implantation. All valves were apparently functioning normally on clinical examination. Peak flow velocity, mean flow velocity, pressure half-time and mean pressure gradient were determined from the transmitral flow velocity curve by CWD echocardiography. For comparison, the same parameters were examined in 15 normal children and 14 adults who had undergone mitral valve replacement. All measured values were greater in adults and children who had undergone valve replacement than in normal children. There were no differences in any parameter in adults or children in whom prostheses 25 mm or larger had been implanted. Although 3 children in whom prostheses 23 mm or smaller had been implanted had greater values for each parameter than those who received 25 mm or larger prostheses, there were no symptoms or signs of mitral stenosis. These data may be useful as guidelines for normal Doppler characteristics for St. Jude mitral valves in children. In an asymptomatic child whose prosthetic valve developed obstruction by granulation tissue overgrowth, each parameter significantly worsened as the heart rate increased. The changes in these parameters in 2 normally functioning St. Jude valves during atrial pacing were insignificant. The fluctuation of Doppler characteristics with changes in heart rate is useful for differentiating normally functioning prosthetic valves from impending stenosis.
Matsuoka
Y
Y
Department of Pediatrics, Miyazaki Medical College, Japan.
Nishiguchi
T
T
Nakachi
T
T
Hayakawa
K
K
Onitsuka
T
T
Koga
Y
Y
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D015150:Echocardiography, Doppler; D005260:Female; D006350:Heart Valve Prosthesis / Q000295:instrumentation; D006439:Hemodynamics; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000502:physiology