Letter by Ren et al Regarding Article, “Acute Heart Failure in Multisystem Inflammatory Syndrome in Children in the Context of Global SARS-CoV-2 Pandemic”
Authors: Chuanli Ren, Manning Qian, Chongxu Han
Journal: Circulation (2021)

We read with great interest the article by Belhadjer et al 1 describing children infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) developing multisystem inflammatory syndrome in children (MIS-C), similar to Kawasaki disease, and experiencing acute cardiac decompensation caused by severe inflammation.MIS-C associated with SARS-CoV-2 infection in China did not receive much attention until the latest national treatment guidelines were issued recently. 2We have some concerns to share with the authors.First, the value of the diagnostic sensitivity and specificity of the serum SARS-CoV-2 antibody is controversial.The authors mentioned that all patients were tested for SARS-CoV-2 infection by reverse-transcriptase polymerase chain reaction, serology, or antigen test.They addressed that a child with MIS-C was considered to have SARS-CoV-2 infection if any of these tests was positive.However, because of the presence of interfering substances (eg, rheumatoid factor, heterophilic antibody, lysozyme) in the blood or an unqualified blood specimen (eg, hemolysis, bacterial contamination, incomplete coagulation), the antibody test may frequently give false-positive results. 2 The Royal College of Paediatrics and Child Health and the Centers for Disease Control and Prevention have applied 2 different judgment standards for MIS-C in children associated with SARS-CoV-2 infection. 3,4Therefore, the serological test is generally not used as a diagnostic method alone, and a comprehensive judgment should be made in combination with other methods.We are concerned that the positive results of Belhadjer et al for the diagnosis of coronavirus disease 2019 (COVID-19) depending only on serum antibody may be misleading.Second, we wonder whether obesity or overweight among those with MIS-C associated with SARS-CoV-2 is an independent risk factor for an acute cardiac decompensation.It was reported that 37% of children with MIS-C in 26 US states were obese. 5Previous studies implied that obesity or overweight was associated with critically ill adult patients with COVID-19.We argue that obesity or overweight is one of the independent risk factors among children with MIS-C for an acute cardiac decompensation other than those infected with SARS-CoV-2.Third, we argue that a panel of routine laboratory test parameters is helpful for early diagnosis of MIC-S with acute heart failure in the context of the global SARS-CoV-2 pandemic.Compared with Kawasaki disease, children with MIS-C who were infected with COVID-19 with cardiovascular involvement had a higher percentage of an increase in white blood cells and neutrophil counts, C-reactive protein, ferritin, NT-proBNP (N-terminal pro-B-type natriuretic peptide), and troponin, whereas platelet and lymphocyte counts were decreased. 1,5e recommend monitoring early-stage blood pressure and evaluating ECG of Letter by Ren et al Regarding Article, "Acute Heart Failure in Multisystem Inflammatory Syndrome in Children in the Context of Global SARS-CoV-2 Pandemic"