Risk assessment of patients with clinical manifestations of cardiac sarcoidosis with positron emission tomography and magnetic resonance imaging.

ABSTRACT

BACKGROUND: Prior studies have shown that late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) and fluorodeoxyglucose (FDG) positron emission tomography (PET) confer incremental risk assessment in patients with cardiac sarcoidosis (CS). However, the incremental prognostic value of the combined use of LGE and FDG compared to either test alone has not been investigated, and this is the aim of the present study. METHODS: Retrospective observational study of 56 symptomatic patients with high clinical suspicion for CS who underwent LGE-CMR and FDG-PET and were followed for the occurrence of death and/or malignant ventricular arrhythmias (VA). RESULTS: The combination of PET and CMR yielded the following groups 1) LGE-negative/normal-PET (n=20), 2) LGE-positive/abnormal-FDG (n=20), and 3) LGE-positive/normal FDG (n=16). After a median follow-up of 2.6years (IQR 1.2-4.1), 16 patients had events (7 deaths, 10 VA). All, but 1, events occurred in patients with LGE. LGE-positive/abnormal-FDG (7 events, HR 10.1 [95% CI 1.2-84]; P=0.03) and LGE-positive/normal-FDG (8 events, HR 13.3 [1.7-107]; P=0.015) patients had comparable risk of events compared to the reference LGE-negative/normal-PET group. In adjusted Cox-regression analysis, presence of LGE (HR 18.1 [1.8-178]; P=0.013) was the only independent predictor of events. CONCLUSION: CS patients with LGE alone or in association with FDG were at similar risk of future events, which suggests that outcomes may be driven by the presence of LGE (myocardial fibrosis) and not FDG (inflammation).