Evaluation of normal prosthetic valve function by Doppler echocardiography

Previous investigations have suggested that Doppler echocardiography is useful in detecting dysfunction in aortic (AVR) and mitral prostheses (MVR). However, to diagnose abnormallties, the spectrum of normal velocities through these valves must be established. Therefore, we used Doppler echocardiography to study 100 patients with 105 prosthestic valves that had no clinical evidence of valve dysfunction 9 ± 8 days postoperatively. There were 66 Carpentler-Edwards (C-E), 23 St. Jude (S-J), and 16 lonescu-Shlley (I-S) valves. In 70 AVR, the peak instantaneous gradient was 26.4 ± 8.2 Hg, mean systolic gradient was 15.6 ± 5 mm Hg, and gradients varied inversely with valve size, although differences were significant only when comparing the smallest vs the largest valve sizes ( p≤0.03). Peak instantaneous gradients >36 mm Hg occurred only in AVR size 23 or smaller. There were no significant differences in gradients among C-E, S-J, and I-S AVR. In 35 MVR, mean gradient was 6.9 ± 2.3 mm Hg and valve area was 2.7 ± 0.8 cm 2; neither varied significantly with valve size. However, S-J MVR group had smaller mean gradients and larger effective valve area than C-E bioprosthetic MVR ( p = 0.01 and p = 0.05, respectively). Regurgitation was more common in AVR (26%) than in MVR (9%), p = 0.04, although all instances were mild and clinically silent. We conclude that normal AVR and MVR of a given size and type have a predictable range of Doppler echocardiographic parameters. Doppler evidence of mild regurgitation is a frequent finding in normal AVR and MVR. The inverse relationship between valve size and gradient should be taken into account when interpreting Doppler echocardiographic measurements in AVR.