Normal values of prosthetic valve Doppler echocardiographic parameters: a review

Exercise Doppler echocardiography in patients with mitral prosthetic valves

Submaximal supine exercise was done by 17 patients with mitral prostheses. Eleven had Björk-Shiley (BS) and six had Starr-Edwards (SE) valves. In 15 patients with normally functioning prostheses, valve area at rest was 2.4 +/- 0.25 cm2 in the BS patients and 1.8 +/- 0.35 cm2 in the SE group (p less than 0.01). In the SE group, peak and mean gradients increased from 8 +/- 1 and 5 +/- 1 mm Hg, respectively, at rest to 22 +/- 5 and 13 +/- 4 mm Hg at peak exercise (mean +/- 1 SD). In the BS group, peak and mean gradients increased from 10 +/- 3 and 5 +/- 2 mm Hg, respectively, at rest to 16 +/- 3 and 10 +/- 3 mm Hg at peak exercise. Peak pressure gradient at peak exercise and the increase in peak gradient with exercise (exercise-resting gradient) were significantly higher in the SE group (p less than 0.05). By plotting the heart rate versus the transmitral gradient during the recovery period, a heart rate-gradient curve was obtained for each type of prosthesis. Doppler echocardiography with moderate supine exercise can be performed in most patients with mechanical prosthesis. Hemodynamic properties (the occlusive character of the SE prosthesis) were brought out by exercise. Doppler echocardiographic measurements during exercise can provide important information, particularly in patients with borderline measurements at rest.

Doppler echocardiographic evaluation of tilting-disc prosthetic heart valves in children

To determine the Doppler characteristics of tilting-disc prosthetic heart valves in children, 22 children with mitral prostheses were studied 8 +/- 2 months after surgery, and 10 children with aortic prostheses were studied 37 +/- 26 months after surgery. All valves were thought to be functioning normally by clinical examination. Valve competence was interrogated and peak and mean velocities were measured by standard pulsed wave, continuous wave and color Doppler techniques. Prosthetic valve area was calculated and compared to the known valve area. Mild prosthetic valve regurgitation was present in 8 of 22 mitral and 7 of 10 aortic prostheses. For mitral prostheses, peak velocity was 192 +/- 41 cm/s, mean velocity was 118 +/- 37 cm/s and mean gradient was 7 +/- 4 mm Hg. For aortic prostheses, peak velocity was 287 +/- 88 cm/s, mean velocity was 197 +/- 59 cm/s, peak gradient was 36 +/- 21 mm Hg and mean gradient was 19 +/- 11 mm Hg. Prosthetic mitral valve area, calculated by the pressure half-time and modified Gorlin methods, correlated well with the known valve area (r = 0.89, standard error of the estimate = 0.29 and r = 0.95, standard error of the estimate = 0.21, respectively). Prosthetic aortic valve area, calculated by the modified Gorlin method, correlated well with the known valve area (r = 0.89, standard error of the estimate = 0.18). Residual valvular abnormalities are common after prosthetic valve insertion in children. Doppler estimates of prosthetic valve area correlate well with the known valve area but have a large standard error of the estimate.

Doppler echocardiography: application to the assessment of successful thrombolysis of prosthetic valve thrombosis

Prosthetic valve thrombosis remains a significant problem despite anticoagulation therapy and advances in valve design. Thrombolytic therapy offers an alternative approach to valve replacement in patients with high surgical risk. In this article we discuss three cases in which Doppler echocardiography was used to confirm the diagnosis of prosthetic mitral valve obstruction and serially monitor the response of valvular hemodynamic measurements to thrombolysis with intravenous streptokinase. These cases illustrate how the Doppler technique, in addition to allowing the noninvasive diagnosis of prosthetic valve obstruction, is presently the ideal tool to follow serially the effect of thrombolytic therapy on prosthetic valve function.