In the case of valvular heart disease, the valves are best studied intact. The atrial and ventricular aspect of the atrioventricular valves and the ventricular and arterial aspects of the semilunar valves are examined (Figure 18.104.22.168). Thus, the tricuspid valve is exposed by a lateral incision through the right atrium from the superior vena cave to 2 cm above the valve annulus. Similarly, the mitral valve may be studied following opening of the left atrium via an incision extending from one of the left pulmonary veins to one of the right pulmonary veins and another incision continuing through the atrium laterally to a point 2 cm above the annulus. If a valve abnormality requires closer inspection, the atria, including the interatrial septum, may be removed 1 to 2 cm above the atrioventricular valves (Figure 22.214.171.124A). The ventricular aspects of the atrioventricular valves may be viewed following removal of the serial slices of ventricle as described previously.
The semilunar valves are best studied after removal of the aorta (Figure 126.96.36.199C) and the main pulmonary artery at a point just above the coronary ostia or valve annulus. In selected cases, the valvular pathology may be best visualized using a four-chamber cut15-17 in the plane including both the acute and obtuse margins of the heart (Figure 188.8.131.52). The aortic valve may be demonstrated by a left ventricular long-axis cut passing from the apex through the outflow tract, ventricular septum, anterior mitral valve leaflet, and aortic valve (Figure 184.108.40.206).
Figure 220.127.116.11 (A) Diagram of the heart demonstrating the ultrasonic tomographic plane used for obtaining the long axis view of the heart. This four-chamber view is best used for evaluating the atrial and ventricular dimensions, intracavitary masses, ventricular and atrial septal defects, atrioventricular valve abnormalities, ventricular aneurysms, and the drainage of pulmonary veins. (B) Diagram demonstrating the four chamber view of the heart. This method involves sectioning the heart from apex to base, along the acute margin of the right ventricle and the obtuse margin of the left ventricle and continuing the plane of sectioning through the atria. The bisected specimen that is photographed should match the ante mortem cardiac image. (C) Tomographic analysis of a heart from a 17-year-old boy who developed progressive heart failure over the course of 8 months, showing four-chamber view with biventricular hypertrophy, four-chamber dilatation, and apical right and left ventricular thrombus. (RA = right atrium; LA = left atrium; VS = ventricular septum; TV = tricuspid valve; AML = anterior mitral leaflet; PML = posterior mitral leaflet) (Modified from Tajik, A.L., Seward, I., Hager, D.J., Muir, D.D., and Lie, J.T., Two dimensional real-time ultrasonic imaging of the heart and great vessels: Technique, image orientation, structure notification and validation, Mayo Clin. Proc., 53:271, 1978. From Virmani, R., Ursell, P.C., and Fenoglio, J.J., Examination of the heart, in Virmani, R., Atkinson, J.B., and Fenoglio, J.J., Eds., Cardiovascular Pathology, W.B. Saunders, Philadelphia, 1991, pp 1-20. With permission.)
Measurement of the circumference of annuli, especially in valvular stenosis, is on the whole not very useful. In ectasia of the aorta, it is indeed a must to measure the aortic annulus as the valve will be normal in appearance but the annulus will be dilated. Examination of the heart valves should document the type and severity of the valvular disease and its effect on the cardiac chambers and this includes microscopic evaluation.
In cases in which histology of a valve may be helpful, the leaflets are sectioned together with a portion of the adjacent chambers and/or vessel walls. For example, the posterior leaflet of the mitral valve is sectioned including a portion of the left atrium and left ventricular free wall, while the anterior leaflet includes ventricular septum and non-coronary cusp of the aortic valve. In cases of rheumatic heart disease, sections of the atrial appendages are submitted for histologic examination because the incidence of Aschoffs nodules is highest in these structures.
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