Doppler echocardiographic evaluation of prosthetic valves in tricuspid position.

Doppler echocardiographic characteristics of 29 normally functioning prosthetic valves (23 mechanical, 6 biological) and 8 obstructed mechanical prostheses in the tricuspid position are reported. In normally functioning prostheses, peak velocity, mean pressure gradient, and pressure-half time were 1.25 +/- 0.18 m x sec(-1), 2.6 +/- 1.1 mm Hg, and 122.6 +/- 30.7 msec, respectively. Although no significant differences were seen in peak velocity and mean pressure gradient between mechanical and biological valves, the pressure half-time was significantly greater in biological valves. All normally functioning prostheses had a mean pressure gradient 5.5 mm Hg and pressure half-time < 200 msec. In obstructed bileaflet valves, peak velocity was 1.66 +/- 0.28 m x sec(-1), mean pressure gradient was 6.1 +/- 2.8 mm Hg, and pressure half-time was 265.8 +/- 171.7 msec. These Doppler data were significantly greater than those in normally functioning valves where the mean pressure gradient was 5.1 mm Hg and the pressure half-time was 156 msec in all except one patient. Pathological obstruction of a tricuspid prosthesis can be strongly suspected in patients with a mean pressure gradient > 5.5 mm Hg and a pressure half-time > 200 msec on Doppler echocardiography.