Etiological Classification and the Role of Malignancy in Constrictive Pericarditis in 21^st Century

Background: Constrictive pericarditis (CP) is an impairment of cardiac filling due to fibrosis and/or calcifications of the pericardium which cause pericardial stiffness. The most common etiology of CP in developed countries is idiopathic or viral. Otheretiologies such as post cardiac surgery or post chest radiation are encountered with lesser prevalence. CP secondary to malignancy is found in 2-5% of patients and carry worse prognosis

Methods: We reviewed 1573 medical records of patients with pericardial disease in Sheba medical center between 2000-2018. We identified 91 patients (6%) with CP. CP was diagnosed by clinical and imaging methods. The etiology of CP was determined by medical history, imaging, macroscopic features at time of surgery and histopathological or microbiology reports

Results: In this cohort CP was considered idiopathic in 47% (43). Infectious cause was in 9% (8) of patients among them 6 were considered to be due to tuberculosis. Post cardiac surgery/procedure was seen in 14% (13), among them cases after perforation, and in 5% (5) were due to auto-immune disease.

We identified 13 % (12) patients with CP related to active malignancy. Thoracic tumor with pericardial involvement and consequent CP was found in 6 patients, most commonly malignant mesothelioma. In 5 cases, patients with active malignancy with or without pericardial effusion had features of CP on echo-Doppler, without histopathological/cytological findings. CP was thought to arise by an inflammatory mechanism or due to a paraneoplastic phenomenon. One case of CP in a multiple myeloma patient occurred after bone marrow transplantation by a GVHD mechanism.

In addition, 9% (8) of cases CP were a sequel of past chest radiation. In 2 cases CP presented years after chemotherapy and was considered as possibly related.

Conclusion: The etiologies of CP are often based on historical series and vary according to period and geographic region. As opposed to previous reports, in our series association with malignancy was quite common comprising 13% active cancer and 9% secondary to chest irradiation for malignant disease.

Malignancy is an important etiology for CP in the 21 centuries, due to direct involvement of the pericardium, or secondary to cancer treatment (radiation or drugs). We hypothesize that some cases of CP associated with malignancy arise by immune-mediated or auto-inflammatory mechanism.