137 - ASSESSMENT OF MYOCARDIAL STRUCTURE AND FUNCTION IN MULTISYSTEM INFLAMMATORY SYNDROME IN CHILDREN USING CARDIAC MRI AND SERUM GALECTIN-3: FOLLOW-UP STUDY AFTER A MEAN DURATION OF 23.58 MONTHS

Background: MIS-C is a novel disease in children and adolescents emerged in April 2020 in context of SARS-CoV-2 pandemic. It is associated with significant myocardial dysfunction and development of CA during acute phase. Although ECHO has been the preferred imaging modality for follow-up of patients with MIS-C, it has several limitations, as it is not a sensitive technique for assessment of myocardial dysfunction. Cardiac Magnetic Resonance Imaging (CMRI) is now being increasingly recognized as a useful imaging modality for myocardial assessment. There is paucity of follow-up data on this subject.

Methods:  This prospective observational study was conducted between July 2022-December 2023 in Allergy Immunology Unit, Advanced Paediatrics Centre, PGIMER, Chandigarh. Diagnosis of MIS-C was based on WHO guidelines. Twelve patients with MIS-C underwent CMRI on 3 Tesla – Siemens Ingenia platform. Serum Galectin-3 levels were also analysed on same day.

Results: Mean age of study cohort was 11.33 years (range 9-13 years). Of the 12 patients, 7(58%) had low ejection fraction (EF < 55%), and 3(25%) presented with CA. ECHO and CMRI were carried out at a mean follow-up of 23.58 months. While ECHO showed normal EF in all patients, CMRI revealed low EF ( < 55 %) in 4 (33.3%) patients. Further, on CMRI 5(42%) had end-diastolic volume < -2 Z score, 1(8.3%) had end-systolic volume < -2 Z score, and 7(58%) had stroke volume < -2 Z score. EF on CMRI was lower (mean-58.34±7.75) in comparison to ECHO (mean-62.33±5.28). Correlation coefficient for EF on CMRI and on ECHO was 0.2. There were no regional wall motion abnormalities or late Gadolinium enhancement in any of the patients. However, 2 (16.6%) patients had abnormal native myocardial T1 values ( >1250ms) suggestive of myocardial fibrosis. None had any CAAs detected on CMRI or ECHO at follow-up. Mean serum Galectin-3 in patients with MIS-C at 23.58 months of follow-up was 13.49±7.63 ng/ml. This was much higher when compared to age-matched healthy controls (mean-7.48±3.13) (p=0.063).

Conclusions: Our study highlights the efficacy of CMRI as a useful imaging modality for long-term assessment in patients with MIS-C. At a mean follow-up of 23.58 months, no patient showed low EF on ECHO, but CMRI detected impairment in 33.3% of cases. Persistent elevation of Galectin-3 suggests ongoing myocardial inflammation. Patients with MIS-C may continue to have functional abnormalities. CMRI appears to be a better imaging modality for diagnosis of myocarditis in this situation, as compared to ECHO.