Sarcoidosis diagnosed on granulomas in the explanted heart after transplantation: Results of a French nationwide study.

Background: Cardiac sarcoidosis (CS) is a challenging diagnosis. Patients may progress to end-stage congestive heart failure and require cardiac transplantation without ever having been diagnosed. Characteristics and outcomes of patients with granulomas in the explanted hearts are unknown.

Methods: All French heart transplantation centers were contacted to participate in the study. Each center searched through local databases for the cases of non-caseating granuloma in the explanted hearts between 2000 and 2017. Data before and after transplantation were recorded from medical charts. Survival of CS and all- cause heart transplantation patients were compared.

Results: Fifteen patients (10 men, 5 women) received a diagnosis of CS based on pathologic data of the explanted heart and were recruited for the study. All patients were diagnosed as non-ischemic dilated or hypertrophic cardiomyopathy and presented congestive heart failure. Eight patients (53%) had ventricular rhythm disturbances, and 3 (20%) a complete heart block. Ten out of 13 patients (77%) had extracardiac radiological signs compatible with sarcoidosis on chest computed tomography (CT) scans. One patient died 3 months after transplantation from infectious complications. The 14 remaining patients were still alive at the end of the study (median follow-up of 28.8 months). One patient had a second heart transplantation 5 years later because of chronic allograft vasculopathy. One patient presented a relapse of CS confirmed by myocardial biopsies 9 years after transplantation, requiring an escalation of immunosuppressive therapy.

Conclusion: CS may be undiagnosed before heart transplantation. In 77% of cases, sarcoidosis could have been detected before transplantation with non-invasive imaging techniques.