[¹⁸F]FDG-PET in cardiac sarcoidosis: A single-centre study in a southern European population

Cardiac sarcoidosis (CS) is clinically diagnosed in 5% of patients with sarcoidosis but imaging studies suggest higher prevalence. We evaluated the prevalence, clinical manifestations, and cardiovascular outcomes of CS, diagnosed through ¹⁸F-Fluorodeoxyglucose positron emission tomography ([¹⁸F]FDG-PET), in a southern European population.

Retrospective single-centre study of patients screened for sarcoidosis with [¹⁸F]FDG-PET. Subjects with histological confirmation were divided in two groups, CS or extracardiac sarcoidosis, according to Heart Rhythm Society's criteria. Primary endpoint was defined as the composite of heart failure hospitalizations, uncontrolled arrythmias, pacemaker implantation, and cardiovascular (CV) mortality. Secondary outcomes included each component and all-cause mortality.

From 128 patients with biopsy-proven extracardiac sarcoidosis, 10.2% had probable CS, 54% without symptoms of cardiac involvement. Ten patients had suggestive [¹⁸F]FDG uptake patterns, three subjects had an indicative cardiac magnetic resonance (CMR). Patients with probable CS had significantly higher prevalence of coronary and valvular disease, heart failure, and atrial fibrillation compared with those without cardiac involvement. During a mean follow-up of 4.0 SD2.7 years, the primary outcome occurred more frequently in patients with probable CS (53.8% vs. 3.5%; HR 25.45; 95% CI 5.27-122.9; p < 0.01) as well as heart failure hospitalizations (46.2% vs. 0.9%), uncontrolled arrhythmias (23.1% vs. 1.7%) and pacemaker implantation (23.1% vs. 0.9%) (p < 0.01 for all). All-cause mortality was three-fold higher in probable CS, despite the absence of statistical significance (15% vs. 5%, p = 0.15).

Among patients with biopsy-proven sarcoidosis, cardiac involvement detected by [¹⁸F]FDG-PET or CMR is associated with a higher risk of CV events, irrespective of symptoms.