Most pathological lesions affect the mitral and aortic valves because they are subjected to higher pressures compared to the tricuspid and pulmonary valves.

Examination of the heart valves within the heart:

Both aspects of valve should be examined.

Tricuspid valve is exposed by a lateral incision through the right atrium from the superior  vena cava to 1cm above the valve annulus.

Similarly, the mitral valve can be studied by opening 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 1cm above the annulus.

Stenosis of this valve can be assessed simply by inserting one, two, or three fingers through the orifice.

By gently squeezing the left ventricle after washing out blood clot, an impression can be formed of whether the cusps are mobile and whether there is any prolapse into the left atrium.

The ventricular aspects of the atrioventricular valves may be viewed following removal of the ventricles.

The semilunar valves are best examined after removal of the aorta and main pulmonary artery 3cm above the origin of both great vessels.

Stenosis of the aortic valve can be assessed by passing a finger through the valve.

More sophisticated techniques such as perfuse fixation for 24 hours with formalin give very exact appreciations of the presence or absence of regurgitation in the aortic and mitral valve but are time consuming and require a pressure pump.

Very good exposure of the aortic and mitral valves can be made by a cut which passes from the left atrium down the lateral margin of the heart through the mitral valve followed by a left ventricular long-axis cut passing from apex through the outflow tract through the aortic valve. Similarly the pulmonary valve and infundibulum may be visualized with a long-axis cut to the right ventricle. Measurements of the circumference of annuli is not very useful in vulvar stenosis but can prove useful in vulvar regurgitation.

Examination of resected valve:

After the surgical specimen is received, all gross morphological observations should be recorded.  Macroscopic examination is far more reliable in determining the nature of valve disease than histological examination.

Features to be recorded include:

Fibrous thickening ; Calcific deposits ; Perforation ; Indentation of valve edge ; Tissue excess ; Commissural fusion ; Vegetations ; Chordae tendineae (fused ; elongated; shortened; ruptured ) ; Abnormal papillary muscles ; Number of semi-lunar cusps and valve annular circumference.

Valves may be radiographed for calcific deposits if the facilities are available. Clinical information from catherization studies and echocardiography as well as operative descriptions are essential to arrive at a proper diagnosis in many cases, specially if the resected valve is received in a fragmented form.

Most of the important features can be fully assessed macroscopically, and in many cases microscopical examination is necessary.

Microbiological culture is essential in any case where infective endocarditis is a possibility and fresh tissue is available.

Clinical presentation:

Age and sex of the patient ;  Presenting features and their duration ;  Family history of heart disease, rheumatic heart disease, infarction ;   Features on examination suggestive of an underlying disease, E.g. amyloidosis , storage disorders. History of immunosuppression, systemic malignancy, relevant travel abroad.

Investigation:  

Laboratory findings: ESR, red and white cell count, blood film picture; Radiological and echocardiographic features and diagnosis; Results of microbiological  and virological investigations;

The microscopical report should comment on the following features:

Vascularization of valve cusps;

Vegetations; fibrin; platelets; organisms; foreign material;

Commissural fusion;

Fibrous thickening and its distribution;

Calcification ;

Mucinous degeneration;

Inflammation:  acute, chronic non-specific, granulomatous;

Amyloid deposition;

Aschoff bodies ( in papillary muscle).

Special stains:

Elastic van Gieson to show valve architecture;

Alcian blue to demonstrate mucinous degeneration ;

Congo red for amyloid ;

Stains for organisms, Eg. Gram, Grocott methenamine silver.