Endomyocardial biopsies may be undertaken for diagnosis of native cardiac conditions and as surveillance for rejection after cardiac transplantation.1,2 Biopsy of cardiac masses such as myxomas, fibroelastomas and adhesions of the heart and large vessels may also occur.3 Occasionally myectomy specimens are taken to relieve outflow obstruction and for diagnosis of cardiac disorders.3 See the reference provided (Recommendations for processing cardiovascular surgical pathology specimens)4 for more detail on clinical scenarios associated with endomyocardial biopsies.
Record the patient identifying information and any clinical information supplied together with the specimen description as designated on the container. See overview page for more detail on identification principles.
- Non-routine fixation (not formalin), describe.
- Special studies required, describe.
- Ensure samples are taken prior to fixation.
Fresh specimens should be transferred to a saline swab for a few minutes prior to fixation to minimise distortion of the muscle (contraction bands).3
Where special studies are indicated, take small pieces of biopsy material and transfer to glutaraldehyde for electron microscopy or appropriate solution for freezing for immunofluorescence, molecular biological (viral nucleic acid) or enzyme analysis.3,4 Myectomy specimens are generally received fresh and can be sampled for electron microscopy and immunofluorescence if required.
Ensure that sufficient tissue remains for routine processing. Generally three or more pieces of endomyocardium, at least 3-4 mm (in max. dimension) are required but in some circumstances five or more may be necessary.4 Transfer to formalin for routine processing.4
Electron microscopy may be used for the assessment of chemotherapy (Adriamycin/Doxyrubicin) toxicity. In these cases, the majority of tissue may need to be submitted for electron microscopy with only a minor sample processed for light microscopy.3,4
See general information for more detail on specimen handling procedures.
Inspect the specimen and dictate a macroscopic description.
Inspect the specimen and identify if endocardium and/or myocardium is present. Cardiac tissues are generally red-tan and unorientated. White tissue may represent areas of scarring and friable fragments may be thrombi and are not suitable for evaluation of cardiac transplant rejection.4
For diagnostic evaluation of rejection by light microscopy an adequate specimen consists of at least three pieces of endomyocardium (but preferably four or more) with myocardium representing at least half each tissue fragment.4
Photograph the intact specimen if required.
Describe the following features of the specimen:
Record as stated by the clinican.
- Endomyocardial biopsy (left/right ventricular)
- Transplant rejection biopsy
- Cardiac tumour biopsy
- Ventricular myectomy
- Other, describe
Anatomical components included (more than one may apply) and dimensions (mm)
Describe and measure the anatomical components present.
- Each piece of tissue, in three dimensions
Small specimens do not require dissection.
Larger myectomy specimens can be sectioned perpendicularly to the endocardial surface at 5mm intervals (as illustrated).
Transfer small formalin-fixed tissue specimens directly into cassettes for processing. Lens paper, biopsy pads or similar are required to prevent loss of tissue during processing.
Submit all sections of larger specimens.
Standard protocols for special stains required for blood vessel specimens should be available.4 Care should be taken to conserve tissue in case ancillary studies are required.
Routine non-transplant endomyocardial biopsy:
- Six levels for H&E
- Special stains on some of the Intervening sections for collagen, elastin, glycogen, iron and amyloid (e.g. Verhoff’s Van Gieson (VVG), Periodic acid Schiff’s (PAS), Perls’ Prussian Blue and Congo Red)
- Retain intervening unstained sections for immunohistochemistry markers as requested (most commonly for amyloid e.g. Amyloid P, Amyloid A, Transthyretin (TTR)5, Immunoglobulin light chains kappa and lambda)
- Nine levels for H&E
- Special stain on an intervening section for collagen and elastin (VVG). Further special stains as requested.
- Retain intervening sections for immunohistochemistry if requested (e.g. lymphocytes and macrophage markers).
See the reference provided (Recommendations for processing cardiovascular surgical pathology specimens)4 for more detail on sectioning and special stains.
Record details of each cassette.
An illustrated block key similar to the one provided may be useful.
Prof Tony Thomas for his contribution in reviewing and editing this protocol.
Block allocation key
||No. of pieces
||No. of pieces
Ardehali H, Qasim A, Cappola T, Howard D, Hruban R, Hare JM, Baughman KL and Kasper EK. Endomyocardial biopsy plays a role in diagnosing patients with unexplained cardiomyopathy. Am Heart J 2004;147(5):919-923
Stone JR, Basso C, Baandrup UT, Bruneval P, et al. Recommendations for processing cardiovascular surgical pathology specimens: a consensus statement from the Standards and Definitions Committee of the Society for Cardiovascular Pathology and the Association for European Cardiovascular Pathology. Cardiovasc Pathol. 2012;21(1):2-16