Quantitative evaluation of myocardial fibrosis in pediatric patients with Kawasaki disease and coronary artery aneurysms by MRI-derived extracellular volume fraction.

Abstract

To quantify myocardial fibrosis in Kawasaki disease (KD) patients with coronary artery aneurysms (CAAs) by MRI-derived extracellular volume fraction (ECV). This prospective study included KD with CAAs and healthy volunteers with cardiac MRI. The image analyses included CAA size and thrombus, late gadolinium enhancement (LGE), global and regional (basal, middle, apex) ECV values. ECV values of the control and KD subgroups were compared, and the independent predictive factors of ECV were explored. The analysis included 49 patients with large CAAs (mean age, 5.87 ± 2.18 [SD]; 40 (81.6%) males), 40 patients with medium (n = 20) and small (n = 20) CAAs (mean age, 5.34 ± 1.96 [SD]; 33 (82.5%) males), and 20 healthy volunteers (mean age, 6.22 ± 1.77 [SD]; 15 (75.0%) males). Patients with large CAAs are more prone to thrombosis than those with medium and small CAAs (p = 0.033). The global ECV value in patients with large CAAs, medium and small CAAs, and controls has a significant difference (34.37% ± 3.33 vs 33.64% ± 3.27 vs 32.23% ± 2.68, p = 0.032, p = 0.038, p = 0.006, respectively). The regional ECV value showed the same trend. There were significant differences between patients with and without coronary thrombosis and LGE (all p < 0.050). Multivariate analysis revealed that coronary artery thrombosis and LGE were independently correlated with the global ECV. KD patients with CAAs have diffuse myocardial fibrosis, and the degree of myocardial fibrosis is more severe in patients with large CAAs and coronary thrombosis and LGE. Question Highlights the unmet need for non-invasive fibrosis quantification in KD, as prior methods (e.g., LGE) lack sensitivity for diffuse fibrosis. Findings ECV elevation (size-dependent) in CAAs, along with thrombosis and LGE, serves as an independent predictor of ECV. Clinical relevance Emphasizes ECV's role in risk stratification and guiding therapy (e.g., thromboprophylaxis), directly linking to patient outcomes.