Serial Cardiac FDG-PET for the Diagnosis and Therapeutic Guidance of Patients With Cardiac Sarcoidosis

Background: Cardiac fluorodeoxyglucose positron-emission tomography (FDG-PET) has emerged as a standard imaging modality for the diagnosis of cardiac sarcoidosis (CS); however, there is a scarcity of data on the use of serial FDG-PET to guide immunosuppressive therapy. The aim of this work was to report our experience using serial FDG-PET for the diagnosis and management of patients with CS, focusing on its utility in ongoing immunosuppression management. Methods and Results: We studied consecutive patients with CS managed at Stanford University from 2010 to 2017. We evaluated our experience using FDG-PET for diagnosis and guidance of immunosuppressive therapy titration in CS. Among 34 patients diagnosed with CS, 16 (47%), 12 (35%) and 14(41%) presented with heart block, heart failure, and ventricular arrhythmias, respectively. FDG-PET proved beneficial in the initial diagnosis in 21 patients (62%). A total of 128 FDG-PET scans were performed (median 3 per patient). Ninety-four FDG-PET scans (73%) resulted in a change in therapy, with 42FDG-PET scans (33%) instrumental for tapering prednisone. Among patients who were initiated on prednisone, the mean dose of prednisone at 1 year was 9.5mg/d. Over a median follow-up of 2.3years, 48% of patients were successfully weaned from prednisone completely, and 20% were weaned to a maintenance dosage of 5–10mg/d. During the follow-up period, transplant-free survival was 88%. Conclusions: The use of serial cardiac FDG-PET for the diagnosis and management of CS was critical for guiding immunosuppression management and resulted in low chronic steroid doses and good disease control within 1 year of diagnosis.