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Doppler echocardiographic evaluation of normal and thrombosed Björk-Shiley mitral prosthetic valves
S Radhakrishnan1, V K Behl, R Bajaj
1Department of Cardiology and Cardiothoracic Surgery, All India Institute of Medical Sciences, New Delhi.
Insights
Doppler echocardiography effectively assesses Björk-Shiley mitral prosthesis function. This noninvasive technique provides crucial quantitative data on pressure gradients and valve area, distinguishing normal from malfunctioning prostheses.
Area of Science:
- Cardiovascular Medicine
- Biomedical Engineering
- Diagnostic Imaging
Background:
- The Björk-Shiley mitral prosthesis is a common prosthetic heart valve.
- Assessing prosthetic valve function noninvasively is crucial for patient management.
- Doppler echocardiography offers a noninvasive method for hemodynamic assessment.
Purpose of the Study:
- To evaluate the Doppler echocardiographic characteristics of normally functioning Björk-Shiley mitral prostheses.
- To determine if Doppler echocardiography can differentiate between normally functioning and malfunctioning prostheses.
- To establish normal Doppler-derived hemodynamic parameters for this specific prosthesis.
Main Methods:
- Doppler echocardiography was performed on 75 patients with clinically and fluoroscopically normal Björk-Shiley mitral prostheses.
- Pressure gradients and mitral valve area were calculated using Doppler-derived data.
- Six patients with suspected prosthesis malfunction underwent Doppler echocardiography for comparison.
Main Results:
- Normal prostheses showed mean Doppler peak and end-diastolic gradients of 9.01 +/- 3.23 mm Hg and 2.36 +/- 1.0 mm Hg, respectively.
- The mean calculated mitral valve area for normal prostheses was 2.58 +/- 0.38 cm2.
- Malfunctioning prostheses exhibited significantly different (higher) gradients and smaller calculated areas compared to normal ones.
Conclusions:
- Doppler echocardiography is a valuable noninvasive tool for assessing Björk-Shiley mitral prosthesis function.
- The technique provides quantitative data on pressure gradients and valve area, aiding in the diagnosis of prosthesis malfunction.
- Doppler echocardiography can reliably distinguish between normally functioning and malfunctioning Björk-Shiley mitral prostheses.
Abstract:
Doppler echocardiographic characteristics of 75 normally functioning Björk-Shiley mitral prostheses were studied in patients whose valvar function was considered normal by clinical and fluoroscopic evaluation. The mean Doppler peak and end-diastolic gradients were 9.01 +/- 3.23 mm Hg, and 2.36 +/- 1.0 mm Hg, respectively. The mean area of the mitral valve calculated by the half-time method was 2.58 +/- 0.38 cm2. No significant difference between the various Doppler parameters was found for the two different valve sizes (25 and 27 mm) studied. Trivial mitral regurgitation was detected in 21 (28%) cases. Doppler echocardiography was performed in six patients with suspected malfunction of the Björk-Shiley mitral prosthesis subsequently confirmed at operation. The end-diastolic gradients in the six patients were 16, 20, 10, 14, 16, and 24 mm Hg, respectively. The calculated areas of the mitral valve were 1.57, 1.37, 1.3, 1.5, 1.46, and 1.3 cm2, respectively. The values of the gradient and calculated areas in malfunctioning valves were very different from those found in normally functioning Björk-Shiley mitral prostheses. It is concluded that Doppler echocardiography is a very useful noninvasive technique for the study of the function of the Björk-Shiley mitral prosthesis and provides quantitative information regarding pressure gradients and valvar area.