Cardiac involvement in children with multisystem inflammatory syndrome (MIS-C) following infection with different SARS-CoV-2 variants

ABSTRACT

Background. MIS-C is a hyper inflammatory condition following SARS-CoV-2 infection. Although COVID-19 infection rates and severity have varied based on circulating SARS-CoV-2 variants, it is unclear if cardiac involvement in MIS-C varies following infection with different SARS-CoV-2 variants. The objective of this study is to describe the severity of cardiac involvement in children with MIS-C following three different waves of SARS-CoV-2 infections. Methods. Children hospitalized with a diagnosis of MIS-C were enrolled in a prospective observational study. Demographic, clinical, laboratory (troponin I and B-type natriuretic peptide (BNP)), electrocardiogram (EKG) and echocardiogram (ECHO) data for children diagnosed between 4/20 and 12/21 and followed at 1- and 6-months was analyzed. The cohort was divided into 3 groups to represent cases that followed infection with the Wuhan (4/20-10/20, group 1), Alpha (B.1.1.7, 11/ 20-7/21, group 2) and Delta (B.1. 617.2, 8/21-12/21, group 3) variants. Cardiac involvement during hospitalization and follow-up was compared between the groups. Results. The cohort includes 131 children with MIS-C (32, 61 and 38 in groups 1, 2 and 3, respectively) with a median age of 10 years. Two-thirds were male (66.4%) and 49.6% were Black. Elevated BNP and troponin I levels were seen in 82% and 52.7% of children at initial diagnosis. A third of the cohort had at least one abnormal EKG finding. The proportion of children with abnormal laboratory and EKG findings was not different between the groups. Decreased left ventricular function on ECHO was seen in 25% (33/131) of the cohort with similar distribution among the three groups (p = 0.79). Trivial-small pericardial effusions were detected in 22% (29/131). Coronary artery abnormalities were detected in 11.45% (15/131), a majority in group 1 (25%;8/ 32). At 1- and 6-monthfollow-up visits, BNP and Troponin I were normal in all children. At the 6-month follow-up visit, EKG was normal in all and ECHO was normal in 37/41 children with trivial to mild valvular regurgitation in four children. Conclusion. In this single center prospective study, while a significant proportion of children with MIS-C had evidence of cardiac involvement at diagnosis, most resolved on follow-up demonstrating good outcomes.