Serial Doppler Gradients Are Predictive of Future Bioprosthetic Valve Degeneration

Doppler echocardiography and color flow imaging are helpful techniques in evaluating the functional status of a bioprosthetic valve. The aim of this study was to determine whether serial Doppler gradients are predictive of future bioprosthetic valve degeneration. We performed serial echo-Doppler studies over a 6-year period (1988-1994) on 228 patients who had undergone mitral (n = 112) or aortic (n = 116) bioprosthetic valve implantation between 1973 and 1994. Thirty-nine mitral prostheses and 30 aortic prostheses became dysfunctional and required reoperation. A serial rise in mean gradient of 5 mmHg or more across the mitral valve and 25 mmHg or more across the aortic valve was significantly associated with increased valve degeneration (odds ratio 3.40 and 16.11 and 95% confidence intervals 1.31 and 8.80 and 13.6 and 72.13 for the mitral and aortic valve, respectively). Both aortic and mitral valves began to degenerate after 8 years. Serial echo-Doppler studies showed a rise in transvalvular gradients around the same time. Closer evaluation for prosthetic valve dysfunction should be considered in patients 8 or more years status post surgery, especially those with high transvalvular gradients.