Cardiac Path Online
Pathology of Cardiac Valve Disease
The cardiac valves are simple tissue and the number of pathological lesions are limited.
Critical information relative to removed valves is obtained from the gross examination of the specimens.
Histologic study is valuable to address specific questions such as endocarditis.
All prosthetic valves, intact native valves and any unusual lesions (vegetations, fibroelastoma) are photographed, as close-up as possible.
Consider both acute and underlying chronic lesions.
Fibrous thickening and calcification are the commonest responses.
The degree varies with the functional lesion and etiology.
Stenotic valves always have severe diffuse fibrous thickening and usually moderate to heavy amounts of of calcific deposits.
In post inflammatory valve disease, the fibrous thickening obliterates the normal trilaminar structure of the cusp and is associated with growth of new vessels into the cusp from the base.
The fibrosis results in commissural fusion and chordal thickening and fusion.
All these features usually lead to stenosis but combinations of fibrous retractions of cusps and chordae with commissural fusion can lead to a mixture of stenosis and regurgitation which is typical of chronic rheumatic disease.
Purely regurgitant valves have mild to moderate degrees of focal superficial fibrous thickening at the free edge due to mechanical trauma, which does not efface the underlying structure of the valve.
Regurgitant atrioventricular valves may have chordae tendineae abnormalities (elongated and/or ruptured) and abnormal papillary muscles with dilated annular circumference.
Calcification is a non-specific response, which occurs in collagen under mechanical stress and with increasing age of the subject.
Calcification causes stenosis and in the aortic valve there is a direct relation between the amount of calcium and the gradient across the valve.
In floppy mitral valve disease the dense collagen of the central fibrous core becomes replaced by more loosely arranged connective tissue rich in glycoaminoglycans and mucopolysaccharides (myxomatous degeneration).
The cusp and chordae elongate and stretch leading to regurgitation.
Vascularisation and calcification are not a feature.
Minimal if any structural valvular alterations can occur in purely regurgitant excised aortic valves associated with aortic root dilatation and the purely regurgitant tricuspid valve excised from patients with pulmonary hypertension, except for dilated annular circumference.
Submit one cassette with representative sections taken from the free edge of the annulus.
It may be necessary to decalcify some specimens.
Endocarditis is a life threatening disease and any indication that acute endocarditis is present should immediately be brought to the attention of the cardiac pathologist and the clinician (ie. either following gross or microscopic examination).
Order Gram stain if there is a question of endocarditis.
Gross Morphologic Assessment of Abnormal Cardiac Valvular Function:
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