Echocardiographic Findings in Pediatric Multisystem Inflammatory Syndrome Associated With COVID-19 in the United States

Abstract

Background: Centers from Europe and United States have reported an exceedingly high number of children with a severe inflammatory syndrome in the setting of coronavirus disease 2019, which has been termed multisystem inflammatory syndrome in children (MIS-C).

Objectives: This study aimed to analyze echocardiographic manifestations in MIS-C.

Methods: A total of 28 MIS-C, 20 healthy control subjects and 20 classic Kawasaki disease (KD) patients were retrospectively reviewed. The study reviewed echocardiographic parameters in the acute phase of the MIS-C and KD groups, and during the subacute period in the MIS-C group (interval 5.2 ± 3 days).

Results: Only 1 case in the MIS-C group (4%) manifested coronary artery dilatation (z score = 3.15) in the acute phase, showing resolution during early follow-up. Left ventricular (LV) systolic and diastolic function measured by deformation parameters were worse in patients with MIS-C compared with KD. Moreover, MIS-C patients with myocardial injury were more affected than those without myocardial injury with respect to all functional parameters. The strongest parameters to predict myocardial injury in MIS-C were global longitudinal strain, global circumferential strain, peak left atrial strain, and peak longitudinal strain of right ventricular free wall (odds ratios: 1.45 [95% confidence interval (CI): 1.08 to 1.95], 1.39 [95% CI: 1.04 to 1.88], 0.84 [95% CI: 0.73 to 0.96], and 1.59 [95% CI: 1.09 to 2.34], respectively). The preserved LV ejection fraction (EF) group in MIS-C showed diastolic dysfunction. During the subacute period, LVEF returned to normal (median from 54% to 64%; p < 0.001) but diastolic dysfunction persisted.

Conclusions: Unlike classic KD, coronary arteries may be spared in early MIS-C; however, myocardial injury is common. Even preserved EF patients showed subtle changes in myocardial deformation, suggesting subclinical myocardial injury. During an abbreviated follow-up, there was good recovery of systolic function but persistence of diastolic dysfunction and no coronary aneurysms.

Keywords: COVID-19; coronary artery abnormality; deformation; echocardiography; multisystem inflammatory syndrome in children (MIS-C); myocarditis.

Graphical abstract

Figure 1

Echocardiographic Image of a Patient With MIS-C With Normal Coronary Arteries Although the coronary artery may appear prominent, the Z score is 1.7 for left anterior descending artery (LAD) and 1.3 for right coronary artery (RCA).

Figure 2

Deformation Parameters in 3 Groups (A) Global longitudinal strain (GLS). (B) Global longitudinal strain rate (GLSR). (C) Longitudinal early diastolic strain rate (EDSR_L). (D) Peak left atrial strain (LAS). Patients with MIS-C were worst affected among 3 groups. KD = Kawasaki disease.

Figure 3

Strain Curves Strain curves in a normal (A) and multisystem inflammatory syndrome in children (MIS-C) patient during acute phase (B) for global longitudinal strain (GLS). (C) GLS curves and (D) left atrial strain (LAS) curves for normal, myocardial injury (+), and injury (−) in MIS-C patients. All MIS-C patients show decreased GLS and LAS compared with normal patients. In addition, myocardial injury (+) patients are worse than injury (−) patients. myo. = myocardial.

Figure 4

Early Diastolic Strain Rate Curves Early diastolic strain rate curves in a normal patient (A), multisystem inflammatory syndrome in children (MIS-C) patient during acute phase (B), and MIS-C patient during early follow-up study (C). Note reduced early diastolic strain rate in the acute phase. During the follow-up study, it still remained lower compared with normal patients. AVC = aortic valve closure; EDSR_L = longitudinal early diastolic strain rate; SR = strain rate.

Figure 5

Deformation Parameters in MIS-C Patients During Acute Stage and Early Follow-Up Period (A) Global longitudinal strain (GLS). (B) Global longitudinal strain rate (GLSR). (C) Longitudinal early diastolic strain rate (EDSR_L). (D) Peak left atrial strain (LAS). During the follow-up study, most MIS-C patients showed recovery of systolic function; however, diastolic function (especially EDSR_L and LA strain) still remained low. FU = follow-up.

Central Illustration

Echocardiographic Findings in Multisystem Inflammatory Syndrome in Children EDSR_L = longitudinal early diastolic strain rate; GLS = left ventricular global longitudinal strain; LAS = peak global left atrial strain; RVFWLS = peak longitudinal strain of the right ventricular free wall.