Endomyocardial biopsy

EMB is an invasive diagnostic method which is described in many references as a gold standard in the diagnosis of myocarditis and ICMP and which definitively confirms the diagnosis and has also an important role in the determination of the disease aetiology [24, 96, 98, 99, 100]. If myocarditis is not confirmed by EMB, it is called clinically suspect myocarditis [96]. In the statement of the European Society of Cardiology, it is even recommended that EMB should be considered in all patients with suspect myocarditis [24]. However, its indication still follows the recommendations of the American and European Society of Cardiology from the year 2007. It is recommended primarily in two clinical scenarios: “1. New-onset heart failure of less than 2 weeks’ duration associated with a normal-sized or dilated left ventricle and hemodynamic compromise. 2. New-onset heart failure of 2 weeks’ to 3 months’ duration associated with a dilated left ventricle and new ventricular arrhythmias, second- or third-degree heart block, or failure to respond to usual care within 1 to 2 weeks.” [123]. The reason for the indication is the exclusion of giant-cell or necrotizing eosinophilic myocarditis because of the specific therapy [16, 123]. It is often indicated also in “heart failure of more than 3 months’ duration associated with a dilated left ventricle and new ventricular arrhythmias, second- or third-degree heart block, or failure to respond to usual care within 1 to 2 weeks.” [123]. When inflammatory changes and non-presence of the agent are found in the myocardium, these patients may be treated with immunosuppressive therapy [29].

The reason for the establishment of these indication criteria was according to the references the absence of unified methodology of indication of this examination and also the fact that in a large part of patients (50 to 70 %) myocarditis heals up without any severe consequences for patients and the performance of EMB would not bring a change of the therapeutic strategy [8].

Even though it is an invasive method, there is described a relatively low incidence of severe complications, around 1 to 2 % [53]. It is a risk of the development of ventricular or supraventricular arrhythmias, damage to the mitral/tricuspid valve or ventricular perforation and the development of cardiac tamponade [53, 123]. Fatal complications were described just in a very small number of cases [124]. The examination specificity is even up to 100 %. The sensitivity varies widely according to the number of taken myocardial samples and the type of the present inflammation, for example for GCM it is 80 to 85 % [123, consultation with Assoc. prof. Kuchynka, M.D., Ph.D.]. The limited diagnostic utilization could be according to the references caused the fact that the myocardial inflammation may be of the focal character and that it is relatively often localized in the subepicardial area [24, 42]. Sensitivity was increased in some studies and case reports with electroanatomic mapping and CMRI for the more accurate localization of the inflammation [61, consultation with Adla, M.D].

The EMB itself is performed by a bioptome which is introduced in patient´s right/left/both ventricles via the right inner jugular vein in the case of the EMB from right ventricle or via the femoral artery in the EMB from left ventricle [100]. The examination is performed under fluoroscopic or ECHO control [125]. There are taken approximately 5 to 10 myocardial samples of a size of 1–2 mm³. Part of them is examined histopathologically (picture 12) and evaluated on the basis of the Dallas criteria. The criteria alone are however according to a number of references insufficient ([42], chapter Histopathology), and thus there are performed routinely even other examinations. It is primarily immunochemical analysis for the evaluation of the inflammatory infiltrate when different monoclonal and polyclonal antibodies are used for the detection of the infiltrate, for example, anti CD3 for the detection of T lymphocytes and anti CD68 for the detection of macrophages [98, 126]. HLA detection is also performed frequently [98, 126]. Myocarditis is confirmed by “the presence of ≥ 14 leukocytes per mm² of a bioptically taken sample of the myocardium including up to 4 monocytes or macrophages per mm² and ≥ 7 CD3+ T lymphocytes per mm²” [5]. According to the type of the infiltrate, myocarditis is characterized into lymphocytic, giant-cell, granulomatous and eosinophilic myocarditis [16, 38]. A part of the myocardial samples examination is aimed at the detection of the agent when it is aimed at pathogens described in chapter Serology. In the case of PVB19, it is recommended to determine the number of copies of the genetical viral material (called as viral load) for the evaluation of the relevance of the finding as a possible disease cause, because the role of PVB19 in aetiology of myocarditis was questioned partly [35]. According to some studies, the evaluation of the replication activity in the myocardium would be beneficial [100].

Picture 12: Histopathological picture of viral myocarditis after autopsy of a patient with the development of congestive heart failure  (autor KGH; https://commons.wikimedia.org/wiki/File:Viral_myocarditis_(1).JPG; https://commons.wikimedia.org/wiki/File:Viral_myocarditis_(2).JPG)

Nuclear methods and cardiac catheterization

Cardiac catheterization is based on the performance of selective coronarography to exclude ischemic heart disease as the cause of a patient´s symptoms. According to the references, other diagnostic relevance is not described [96, 100].

Nuclear methods are used primarily for the detection of cardiac sarcoidosis, primarily FDG PET scan which may detect active myocardial inflammation [50].

Author of the opening picture: KGH

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References:

5) MAISCH B., BÜLTMAN B., FACTOR S., GRÖNE H.-J. et al. World Heart Federation Consensus Conferences Definition of Inflammatory Cardiomyopathy (Myocarditis): Report from two Expert Committees on Histology and Viral Cardiomyopathy. Herz [online]. 2000, 25 (3), 200-209 [cit. 2016-08-26].

8) ZEMÁNEK D. Kapitola 15: Zánětlivé onemocnění myokardu. In: VESELKA, J. a V.ROHN. Kardiovaskulární medicína [online]. 1. vydání. Brno: Fasta Medica, 2015. ISBN 978-80-88056-00-3.

16) KUBÁNEK M., Kapitola 8.2.: Myokarditidy. In: KAUTZNER J., MELENOVSKÝ V., et al. Srdeční selhání – aktuality pro klinickou praxi. Praha: Mladá fronta a.s., 2015. pp. 147–157. ISBN: 978-80-204-3573-6.

24) CAFORIO, A.L.P, PANKUWEIT S., ARBUSTINI E., et al. Current state knowledge on aetiology, diagnosis, management, and Therapy of myocarditis: a position statement of the European Society of Cardiology Working Group on Myocardial and Pericardial Disease. European Heart Journal. 2013, 34(-), 2636–2648.

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35) KUETHE, F., J. LINDNER a et al. Prevalence of Parvovirus B19 and Human Bocavirus DNA in the Heart of Patients with no Evidence of Dilated Cardiomyopathy or Myocarditis. Clinical Infectious Diseases. 2009, -(49), 1660-1666.

38) ŠTEINER, I. Kardiopatologie: pro patology i kardiology. Praha: Galén, 2010. ISBN 978-80-7262-672-4.

42) L., BAUGHMAN. Diagnostika myokarditidy: Dallaským kritériím odzvonilo. Circulation-CZ. 2006, 5(1), 7-9.

50) KUBÁNEK a VOSKA L. Obrovskobuněčná myokarditida a sarkoidóza srdce – update 2015. Kardiologická revue – Interní medicína. 17(4), 295-299.

53) K., BENNETT a et al. Evaluation of the Role of Endomyocardial Biopsy in 851 Patients With Unexplained Heart Failure From 2000–2009. Circulation: Heart Failure [online]. 2013, 2013(6), 676-684 [cit. 2017-02-05].

96) Onemocnění myokardu: Myokarditida, zánětlivá kardiomyopatie. ECardio.cz [online]. -: -, – [cit. 2017-01-30].

98) KINDERMANN, I. a et al. Update on Myocarditis. Journal of the American College of Cardiology. 2012, 59(9), 779-792.

99) KUCHYNKA, P. a et al. Myokarditida a zánětlivá kardiomyopatie. Kapitoly z kardiologie. 2013, 3(-), 87-91.

123) COOPER, L.T., Jr. a et al. The Role of Endomyocardial Biopsy in the Management of Cardiovascular Disease. JACC. 2007, 50(19), 1914-1931.

124) DECKERS, J.W. a et al. Complications of Transvenous Right Veatricular Endomyocardial Biopsy in Adult Patients With Cardiomyopathy: A Seven-Year Survey of 546 Consecutive Diagnostic Procedures in a Tertiary Referral Center. JACC [online]. 1992, 19(1), 43-47 [cit. 2017-02-27].

125) FROM, A.M. a et al. Current Status of Endomyocardial Biopsy. Mayo Clin Proc. [online]. 2011, 86(11), 1095-1102 [cit. 2017-02-27].

126) LEONE, O. a et al. 2011 Consensus statement on endomyocardial biopsy from the Association for European Cardiovascular Pathology and the Society for Cardiovascular Pathology. Cardiovascular Pathology. 2012, 21(-), 254-274.