Serologic Markers of Systolic Dysfunction in MIS-C: Can Echocardiogram Be Deferred?

Background: Cardiac dysfunction is a common and severe manifestation of Multisystem Inflammatory Syndrome of Children (MIS-C). Assessing cardiac dysfunction on presentation is important in determining the most appropriate acute management for the patient, but obtaining an echocardiogram can be challenging to obtain on acute presentation. The purpose of this study was to determine what factors at presentation may be associated with the presence of cardiac dysfunction on admission.

Methods: We performed a retrospective cohort study of all children <21 years of age admitted to a single institution with eventual diagnosis of MIS-C between March 2020 and May 2021. We performed multivariable logistic regression to identify the association of demographics, presenting symptoms, and admission laboratory values with left ventricular systolic dysfunction (defined as left ventricular ejection fraction of <55%) on admission echocardiogram. We excluded patients with initial workup and treatment at an outside hospital from all analyses, and for the analyses of laboratory values we excluded those who did not have sufficient laboratory values obtained within 8 hours of initial presentation.

Results: Of 268 children identified, 237 were eligible for this study and 214 had complete laboratory values. Participants were predominantly male (57%) with a median age of 9.1 years (IQR 6.0-12.6 years). The majority of patients were of non-Hispanic African American race/ethnicity (58%); other common race/ethnicities included non-Hispanic white (21%) and Hispanic or Latino (18%). Older age and elevated levels of brain natriuretic peptide (BNP), troponin, C-reactive protein, ferritin, and white blood count were associated with left ventricular systolic dysfunction on univariate analysis, but only elevated BNP and troponin were significant on multivariable analysis. When abnormal cutoffs were applied, BNP >100 pg/mL and troponin >0.045 ng/mL were associated with left ventricular dysfunction (ROC=0.73), with odds ratios of 3.56 (95% CI: 1.51-7.04, p=0.003) and 2.92 (95% CI: 1.42-6.00, p=0.004), respectively. Patients with both an elevated BNP and elevated troponin had a 50% likelihood of having left ventricular dysfunction on admission echocardiogram, whereas those with neither had an 8.5% likelihood (Table).

Conclusion: Based on our findings, a model using BNP and troponin levels had reasonable predictive value for or against systolic dysfunction on presentation. These findings have important implications in the timely and appropriate use of echocardiogram to assess for systolic dysfunction in the evaluation of MIS-C.