Doppler echocardiographic characteristics of the Carpentier-Edwards xenograft.

In order to define ranges of normal velocities for the Carpentier-Edwards xenograft, 38 mitral, 24 aortic and 9 tricuspid prostheses were studied with pulsed or continuous wave Doppler at a mean interval of 38 months following surgery. All patients had clinically normal prosthetic valve function and no clinical or radiographic signs of heart failure. Mean peak velocity across aortic prostheses was 244 cm s-1 (SD 48). There was weak correlation (r = 0.54, P less than 0.01) between peak velocity and time since valve implantation, but no significant difference in peak velocity across valves of different size. In the mitral position, mean peak velocity was 164 cm s-1 (SD 24) and mean pressure half time 90 ms (SD 23). There was again no significant difference between valves of different size. There was a weak correlation between pressure half time and time since implantation (r = 0.44, P less than 0.01), but there was no relationship between the latter and peak velocity. In the tricuspid position, mean peak velocity was 150 cm s-1 (SD 12) and mean pressure half time 163 ms (SD 50). The Doppler indices of obstruction to blood flow for prostheses in the mitral and aortic positions showed a significant increase with time after implantation.