Issue 4 - August 2010 - Pacini Editore

166
• the absence in many Centers of a team approach integrating
the competences of pathologists and clinicians.
Important prerequisited in using appropriately EMB 2 are:
• perfoming EMB in Centers with a high volume of cases and
expert operators, in order to minimize procedural risks;
• improving pathological diagnostic reproducibility and reducing
the percentage of nonspecific pathological diagnoses,
referring patients to Centers with an expert cardiovascular
pathologist and making use of adequate protocols and
standardized diagnostic criteria;
• optimizing EMB diagnostic sensitivity limits in multi-microfocal
diseases, in common with all other non-targeted
bioptic techniques, applying when warranted imaging techniques
able to focus on the sampling site.
Since the 1970’s, when EMB was beginning to come into
diagnostic use for heart transplanted patients, the indications
for diagnostic EMB have become increasingly more targeted
and the protocols more elaborate resulting in an increased
potential for information.
Recently, in evidence of the renewed interest in EMB, major
Guidelines have been published:
• the joint clinical Guidelines of the American Heart Association,
the American College of Cardiology and the Europen
Society of Cardiology 3 ;
• the Position Paper on Endomyocardial biopsy promoted
by the “Association for Italian Cardiovascular Pathology”,
a jointly document produced by Italian cardiovascular
pathologists and the representatives of the main Italian
cardiologic scientific societies 2 . Part II of the document
specifically addresses everyday diagnostic practice, dealing
with the diagnostic role, particular technical notes,
protocols and diagnostic criteria for each cardiac disease
requiring EMB.
The principal clinical conditions that require EMB are cardiac
failure 4 5 , rhythm disorders 6 , cardiac masses 7 and heart
transplantation 8 .
Here let us confine ourselves to cardiomyopathies 9 10 , the specific
topic of the Symposium, whose complexity is very much
stresses by the most recent classifications.
The diagnostic iter in cardiomyopathies starts when a cardiologist
identifies some clinical, functional and morphological
phenotypes, frequently aspecific and potentially caused by
numerous different diseases, whose course and therapies are
very different.
Here the role of pathologist 2 is:
• to give a definite diagnosis, when possible;
• to exclude some diseases, guiding forwards a diagnostic
program;
• to provide useful information for therapeutic choice and
prognosis;
• to contribute to monitoring the clinical evolution of the
disease and therapeutic program efficacy;
• to help decrease diagnostic errors 11 ;
• to guide genetic tests, when appropriate.
It is noteworthy that, even if the main target of a diagnostic
test is to identify a specific disease, excluding certain diseases
is equally important, especially when the clinical picture is
aspecific.
The diagnostic potential of EMB in various cardiac diseases
may be very different, so the level of its diagnostic contribution
in a specific disease may vary from a definite diagnosis
to a probable diagnosi, to a possible diagnosis, or even an
aspecific picture 2 .
The most significant contribution of EMB is in the diagnosis
of secondary myocardial diseases 10 , either involving only
5 th triennial congress of the italian society of anatomic Pathology and diagnostic cytoPathology
or mainly the heart or as a part of a multi-organ systemic
disease.
It is possible to optimize EMB diagnostic accuracy by taking
certain precautions, which may be considered general rules:
• careful selection of EMB candidates 4 and the evaluation
of EMB effects on the overall clinical management of
the patient. EMB is performed only after the other basic
clinical-instrumental tests have already excluded various
diseases and focused more closely on a possible diagnosis.
An appropriate indication for EMB is the first step towards
decreasing nonspecific diagnoses.
• Appropriate EMB timing and adequate bioptic sampling 12
with multiple specimens, from different sites 13 (possibly
guided by imaging techniques) in various cardiac diseases.
• The knowledge of diagnostic potential in various cardiac
diseases.
• The use of protocols in which the traditional histological
examination should be supported by other tissue investigation
techniques (histochemical, histoenzymatic, immunohistochemical,
molecular, ultrastructural), opportunely
selected on the basis of the histological picture or of clinical
suspicion.
By way of example, I will describe the EMB diagnostic role
and the tissue investigations required to increase information
in some cardiomyopathies.
Inflammatory cardiomyopathies 2 . EMB, integrating the information
from the histological picture, immunohistochemical
tests, molecular tests checking of possible viral genomes 14 ,
may rapidly provide:
• a definite diagnosis of myocardial involvement;
• the etiology ot the disease in many cases;
• the degree of activity of the disease;
• monitoring of the disease course and the efficacy of therapy;
• cardiac localization in inflammatory systemic autoimmune
diseases.
Appropriate EMB timing and adequate sampling are essential.
Amyloidotic Cardiomyopathy 2 . EMB is the only test able to
reach a definite diagnosis of myocardial involvement.
Moreover, when it is included in a complete clinical-instrumental
program, it may:
• contribute to etiological diagnosis using immunohistochemical
tests on both histological and ultrastructural specimens,
to identify the main fibrillar component;
• provide further morphological data as to location, amount
and type of distribution of deposits, myocardial damage and
any associated inflammatory reactions;
• guide genetic analysis in familial forms.
Definite diagnosis of cardiac involvement and identification
of type of amyloidosis is essential for therapy.
Arrythmogenic right ventricle cardiomyopathy 2 . EMB is a
major diagnostic standard in the score system for the diagnosis
of ARVC and it may provide:
• probable diagnosis of cardiac involvement showing myocardial
atrophy with fibrosis or fibro-fatty replacement and
differential diagnosis with myocarditis, sarcoidosis, dilated
cardiomyopathy and idiopathic forms;
• evaluation of the extent of myocite morphologic compromise.
Diagnostic accuracy increases if the site of bioptic samples is
selected using imaging- or electroanatomic voltage mappingguided
techniques
Cardiomyopathies in storage diseases 2 . (Glycogenoses,
Anderson-Fabry disease, Desmin related cardiomyopathy).