[Differentiation of malignant from nonmalignant, inflammatory pericardial effusions with biomarkers]

Disorders of the pericardium are commonly associated with pericardial effusion. Its etiology comprises a broad spectrum of diseases including also malignancies. Pericardiocentesis, pericardioscopy and targeted epicardial biopsy with consecutive pericardial fluid and epicardial biopsy analysis by cytology, molecular biology and immunology establish the underlying etiology in the majority of cases. Of particular therapeutic and prognostic importance is the definite differentiation of malignant pericardial effusion from benign pericardial effusion. Biomarkers for cardiovascular diseases can be divided into biochemical, histological, immunologic, serologic and molecular markers as well as imaging biomarkers. Biomarkers have proven to be useful in the diagnosis, differential diagnosis and prognosis of ischemic heart disease and heart failure. With respect to pericardial disorders, a comprehensive approach combining clinical information, imaging biomarkers, biomarkers of pericardial effusion and analysis of epicardial biopsies often leads to the definite etiologic diagnosis of pericardial effusion. Computed tomography and magnetic resonance imaging allow further characterization of the effusion and, of note, also of the surrounding tissue, which is of particular interest in case of malignancies. Biomarkers of pericardial effusion include biochemical markers, autoantibodies, tumor markers, and cytokines. Analysis of pericardial fluid specific gravity, protein level and lactate dehydrogenase (LDH) separates transudates from exsudates. High adenosine deaminase levels (ADA) and low levels of carcinoembryonic antigen (CEA) in the pericardial effusion are observed in tuberculous pericarditis allowing the differentiation from malignant pericardial effusion. Additional markers, such as interferon and lysozyme, have also been suggested for the diagnosis of tuberculous pericarditis. Tumor markers in pericardial fluid have been used to diagnose malignant pericarditis. CEA levels are significantly higher in malignant than benign effusion. By a cutoff level of CEA > 5 ng/ml the diagnostic sensitivity and specificity are 75% and 100%, respectively, in the diagnosis of malignant pericardial effusion. Further analysis of cytokines and mediators, serologic, immunologic and inflammatory markers may help to understand the pathophysiology of the pericardial disease and provide useful diagnostic information.