Longitudinal Cardiac Outcomes of Multisystem Inflammatory Syndrome in Children: A Systematic Review and Meta-Analysis

There is a paucity of longitudinal data on cardiac outcomes in multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19. We aimed to investigate the longitudinal cardiovascular outcomes in MIS-C. PubMed and EMBASE were searched through May 2022. Observational studies were included, reporting mid-term (≥ 3 months) outcomes in children (aged < 21) with MIS-C. Data were extracted by two researchers. Longitudinal outcomes were synthesized by a one-group meta-analysis using a random-effects model. Eleven studies with a follow-up period (3 months to 1 year) were identified, including 547 MIS-C patients. The mortality was 2.5% (95% CI 1.3–4.9). The majority of left ventricular (LV) systolic dysfunction present in 46.8% (95% CI 32.7–61.3) in the acute phase resolved by 3 months, and the prevalence of LV systolic dysfunction was 1.7% (95% CI 0.5–5.7) and 2.1% (95% CI 0.8–5.4) at 3 month and 6 month follow-up, respectively. Additionally, the persistent LV systolic dysfunction in the small population was mild. However, coronary abnormalities such as coronary artery dilatation or aneurysms, seen in 23.7% (95% CI 17.7–31.1) at baseline, persisted in 4.7% (95% CI 1.5–14.3) at 3 months and 5.2% (95% CI 3.0–8.9) at 6 months. Mitral regurgitation (MR), which was observed in 56.6% (95% CI 27.7–81.6) at baseline, also persisted in 7.5% at 6 months. In conclusion, our study demonstrated largely favorable cardiac outcomes, suggesting resolution of LV systolic dysfunction in the majority of cases. However, coronary abnormalities and MR persisted in a subset of patients at mid-term follow-up.