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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.
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Leaflets or
cusps:
Number of
recognisable leaflets (atrio-ventricular valves) or cusps (semilunar
valves), size, consistency (thickened, fibrotic, calcified,
thinned, redundant [ballooned] , perforated), additional
fragments.
If
abnormality present:
Distribution (focal, diffuse), surface (atrial , ventricular,
both), location (free edge, base).
Commissures:
Relationship
to each other (fused, completely, partially)
Chordae
tendineae:
Length
(shortened, elongated), status (intact, thickened, ruptured,
fused).
Papillary muscles:
Dimensions,
abnormalities (hypertrophied, elongated, scarred).
Vegetations:
Colour,
size, location, consistency (firm, friable) , ?destructive
to underlying tissue. |
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:
|
Pathologic feature |
Stenotic valve |
Purely regurgitant valve |
| Valve
weight |
Increased |
Normal or slightly increased or decreased |
| Fibrous
thickening |
Diffuse |
Diffuse, focal or none |
| Calcific
deposits |
Heavy |
Minimal (if any) |
| Tissue
loss (perforation)
|
None |
May be present
|
| Vegetations
|
Minimal |
May be present |
| Commissural
Fusion |
May be present |
Minimal (if any) |
| Annular
circumference |
Normal |
Normal or increased |
| Number
of cusps |
1, 2 or 3 |
2 or 3 |
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For Mitral (or Tricuspid) valves : |
| Abnormal
papillary muscles |
No |
May
be present |
| Chordae
tendineae Fusion |
Usually present |
Absent |
| Elongation |
Absent |
May be present |
| Shortening |
Usually present |
May be present |
| Rupture |
Absent |
May be present |
A practical approach to examination of cardiac
valves
CARDIAC VALVE DISEASE
MITRAL VALVE DISEASE
PULMONARY VALVE DISEASE
TRICUSPID VALVE
DISEASE
Etiology of
valvular heart disease.Expert
Rev Cardiovasc Ther. 2003 Nov;1(4):523-32.
Etiology of valvular heart disease.Curr
Opin Cardiol. 1996 Mar;11(2):98-113
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