Abstract 11404: Phenotyping Cardiac Sarcoidosis With PET/MR: Imaging Characteristics, Treatment Response, and Outcomes of Isolated Cardiac Sarcoidosis versus Extra-Cardiac Sarcoidosis With Cardiac Involvement

Abstract

Introduction: Diagnosing cardiac sarcoidosis (CS) remains challenging due to limitations of available clinical criteria and low yield of endomyocardial biopsy. PET-MR imaging allows for multidimensional non-invasive assessment of suspected CS. However, the true diagnostic and prognostic impact of these modalities require further exploration. Hypothesis: PET-MR can phenotype CS and its associated treatment response. Methods: We identified 100 patients with known or suspected CS (52±1.8 years, 66% male) who underwent PET-MR imaging: 38 individuals with isolated CS (ICS) (50±1.8 years, 65% male) and 62 subjects with CS and biopsy-proven extra-cardiac sarcoidosis (ECS) (52±2.4 years, 66% male). A subset of 56 patients (24 ICS and 32 ECS) was classified as the phenotype cohort if they were: 1) treatment naïve, 2) started on immunosuppressant treatment after PET, and 3) had follow up PET to assess treatment response, which was graded as complete (CTR), partial (PTR), and no response (NR). PET-MR phenotype was graded as combined imaging findings suggestive of CS (Figure 1A), equivocal for CS, and not suggestive of CS. Major adverse cardiovascular events (MACE) were defined as sustained ventricular tachycardia, ventricular fibrillation, heart transplantation and/or cardiac death at 1 year. Results: From the ICS phenotype cohort, PET-MR findings suggestive of CS were present in 100% (8/8) of patients with biopsy-proven ICS vs. 56% (9/16) of subjects without biopsy (P=0.03). CTR/PTR rates were overall higher in ECS compared to ICS (81% vs. 58%; P=0.06), and in patients with PET-MR suggestive of CS (P=0.01; Figure 1B), in both the ECS (P=0.04) and ICS (P=0.08) groups. MACE events were significantly greater in ICS vs ECS (HR 3.9 [1.6 - 9.7]; P=0.003), and in patients with PET-MR suggestive of CS (HR 8.2 [1.1 - 62]; P=0.04; Figure 1C). Conclusion: PET-MR can identify phenotypes of CS which have distinct disease manifestations, treatment response rates, and clinical outcomes.