Midwall late gadolinium enhancement predicts adverse outcomes in pediatric myocarditis
A Dennee, A J Kiener, H J Tadros, T T DoanAbstract
Background
Pediatric acute myocarditis is associated with variable recovery and risk of adverse cardiac outcomes. Late gadolinium enhancement (LGE) detected by cardiac magnetic resonance (CMR) plays an important diagnostic role, but the prognostic significance of specific LGE patterns in children remains uncertain.
Purpose
To evaluate whether midwall LGE on early CMR is associated with long-term adverse outcomes in pediatric myocarditis.
Methods
A retrospective cohort study was conducted, including patients <21 years old with myocarditis determined by Lake Louise criteria on CMR performed within 30 days of clinical diagnosis. Midwall LGE was defined as mid-myocardial LGE on visual assessment. A composite adverse endpoint was defined as the diagnosis of dilated cardiomyopathy (DCM), arrhythmogenic cardiomyopathy (ACM), or recurrent myocarditis. Associations between midwall LGE and adverse outcomes were evaluated using univariate Cox proportional hazards regression. Event-free survival was assessed using Kaplan–Meier analysis (time 0 = date of diagnosis) with log-rank testing.
Results
A total of 81 patients met inclusion criteria with the initial CMR performed at a median age of 14.8 years (IQR 11.8-16.6), and 23 (28%) were female. Midwall LGE was present in 25 patients (31%; Table 1). Over a median follow-up period of 2.2 years (IQR 0.7-4.3), 14 patients (17%) experienced a composite adverse endpoint, including DCM (n=6; 1 death), ACM (n=6; 2 heart transplants), and recurrent myocarditis (n=2). This occurred more frequently among patients with midwall LGE (32% vs 11%, p=0.03). Event-free survival was lower among patients with midwall LGE (Figure 1) with a nearly threefold increased hazard of adverse outcome (HR 2.9, 95% CI 1.0-8.4, p=0.047).
Conclusion
In pediatric CMR-confirmed myocarditis, midwall LGE on early CMR is associated with an increased risk of adverse outcomes. Initial CMR findings may provide prognostic value and aid risk stratification.