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Endomyocardial Biopsies - Processing of Specimens
Right, or occasionally left, heart biopsies taken by catheter are most often performed to evaluate graft status in
cardiac transplant patients and less commonly to evaluate
Rarely, an endomyocardial biopsy will be performed to diagnose an intracavitary or myocardial tumour.
Processing the specimen:
1) Describe the specimen, including the number of fragments (carefully check lid and sides of container), size and colour. (myocardium = tan ; scar = white ; clot = red/brown).
Describing the needles that may accompany the specimen is not necessary.
However, there should be an equal number of needles and tissue fragments.
Four fragments of myocardium (>50% of each fragment) are required to adequately assess for rejection.
2) Wrap in lens paper and submit in one cassette.
I) Transplant recipients: These are urgent cases.
Order for three Haematoxylin & Eosin and one unstained sections.
Tissue should be saved for special studies (Example: Electron microscopy).
II) All other cases : These specimens are not urgent cases, except by special request.
Order for Haematoxylin & Eosin, one Massonís trichrome, and two unstained sections (to be available for iron, or amyloid stains if needed).
A piece of tissue is submitted to the Electron microscopy laboratory if received in gluteraldehyde (Karnovskyís fixative).
Semi-thin sections are examined on all such cases with a decision for further analysis after examination.
A good sampling consists of three fragments for light microscopy, one fragment for Electron microscopy and an additional fragment for freezing, if there is a suspicion of a metabolic disease.
When evaluation for adriamycin toxicity is the major consideration, all tissue is submitted to the Electron laboratory for embedding in plastic.
Endomyocardial Biopsies - Consultation:
Endomyocardial biopsy consultations consist of slides or wet tissue (in formalin or gluteraldehyde or both).
- Formalin-fixed wet tissue is submitted for processing. Order one Haematoxylin & Eosin, one Massonís trichrome, and three blank slides.
- If slides and/or formalin fixed wet tissue (at least 3 pieces total) are available then gluteraldehyde fixed tissue is sent to the electron microscopy laboratory for processing to semi-thin sections.
A subsequent decision will be made whether to examine ultrathin sections in the transmission electron microscope.
- If only gluteraldehyde-fixed wet tissue is available (ie. no slides or formalin fixed tissues are received), then consult with the cardiac pathologist before processing.
Indications for Cardiac Biopsy:
- Cardiac rejection detection.
- Assessment of the myocardium in Adriamycin therapy (endomyocardial biopsy obligatory).
- Differential diagnosis of restrictive cardiomyopathy (endomyocardial biopsy desirable).
- Tissue diagnosis in suspected myocarditis.
- Diagnosis of dilated cardiomyopathy.
Cardiac biopsy has almost no part to play in the diagnosis of hypertrophic cardiomyopathy or ischaemic heart disease.
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