Clinical and research fellow University of Ottawa Heart Institute Ottawa, Ontario, Canada
Background: Cardiac Magnetic resonance (CMR) may play a role in sudden death risk stratification in patients with sarcoidosis; however more data are required. Recently, in a landmark paper, Athwal PSS. et al. described distinct CMR phenotypes, based on scar patterns described on gross pathology of patients with Cardiac Sarcoidosis (CS) [1]. In a retrospective analysis, they found that patients with LGE in a pattern similar to that very frequently found on pathology, had by far the greatest risk. Our study aimed to externally and prospectively validate these results, using patients from the Cardiac Sarcoidosis Multicenter Cohort study (CHASM-CS; NCT01477359).
METHODS AND RESULTS: Methods This was a two center sub-study of the CHASM-CS study. We identified patients prospectively enrolled in the CHASM-CS study with known or suspected cardiac sarcoidosis. MRIs were overread read by the study corelab, and all readers were blinded to outcomes. Patients were classified into three groups based on the CMR LGE findings as pathology rare, pathology frequent and no LGE. LV subepicardial, multifocal, septal and/or RV free wall involvement were defined as pathology frequent while all other LGE patterns were defined as pathology rare (reproducing exactly the definitions and methodology of Athwall et al). The primary endpoint was ventricular arrhythmia (defined as lasting for > 30 seconds or terminated by ICD intervention). Survival analysis was performed by constructing Kaplan Meier curves among the three cohorts of LGE phenotypes.
Results A total of 208 patients, mean age 56±11yrs, 121/208 (58%) males, were included in the study. Pathology frequent accounted for 85/208 (41%) while patients with pathology rare and those with no LGE accounted for 25/208 (12%) and 98/208 (47%) respectively. Twenty-two patients (11%) had a primary endpoint during a median follow-up period of 4.5 (0.1-14) years. Kaplan Meier survival curve shows significantly lower event free survival among patients with pathology frequent phenotypes compared to cohorts with pathology rare phenotype and cohort with no LGE with similarly favorable survival (p < 0.001).
Conclusion: Our study confirms the prognostic utility of CMR LGE phenotyping in the risk stratification of patients with CS.
