Cardiac Magnetic Resonance Findings after Multisystem Inflammatory Syndrome in Children

Ocular hemodynamics in multisystem inflammatory syndrome in children: A cross-sectional study

PURPOSE

To evaluate retinal vascular changes by optical coherence tomography angiography (OCTA) in multisystem inflammatory syndrome in children (MIS-C).

METHODS

This cross-sectional study included 21 patients who were diagnosed with MIS-C and had a history of hospitalization, 20 pediatric outpatients with a coronavirus disease 2019 (COVID-19) diagnosis, and 26 healthy children. All patients underwent a detailed ophthalmologic examination and OCTA. In the MIS-C and pediatric COVID-19 groups, these evaluations were made 6 months after diagnosis. The vascular density values of the superficial, deep, and radial peripapillary capillary plexuses (SCP, DCP, and RPCP, respectively), foveal avascular zone (FAZ) parameters (area, perimeter, acircularity index, and foveal density), and outer retinal and choriocapillaris flow area values were recorded using OCTA.

RESULTS

No pathology was detected in the ophthalmologic examinations of the three groups with similar age and gender distributions. Although the vascular density values of SCP, DCP, and RPCP were found to be higher in most quadrants in the MIS-C group, there was no statistically significant difference among the three groups ( P > 0.05 for all). FAZ parameters and flow area measurements were similar in all three groups ( P > 0.05 for all).

CONCLUSION

This is the first study to evaluate relatively long-term outcomes in patients with MIS-C and pediatric COVID-19 together. This study shows no changes in the SCP and DCP parameters in pediatric age group, which shows that ocular hemodynamic changes may not be reflected on OCTA after 6 months.

CMR Findings in the Long-Term Outcomes After Multisystem Inflammatory Syndrome in Children (MUSIC) Study

BACKGROUND

Multisystem Inflammatory Syndrome in Children is characterized by high rates of acute cardiovascular involvement with rapid recovery of organ dysfunction. However, information regarding long-term sequelae is lacking. We sought to characterize the systolic function and myocardial tissue properties using cardiac magnetic resonance (CMR) imaging in a multicenter observational cohort of Multisystem Inflammatory Syndrome in Children patients.

METHODS

In this observational cohort study, comprising 32 centers in North America, CMR studies were analyzed by a core laboratory to assess ventricular volumetric data, tissue characterization, and coronary involvement.

RESULTS

A total of 263 CMRs from 255 Multisystem Inflammatory Syndrome in Children patients were analyzed. The mean patient age was 11.4±4.4 years. Most studies were performed at 3 months (33%) or 6 months (45%) after hospitalization. Left ventricular dysfunction was present in 17 (6.7%) of the first CMRs and was never worse than mild. Dysfunction was observed in 4/7 (57%) patients at admission, 5/87 (6.9%) patients at 3 months, and 6/129 (4.6%) patients imaged either at 6 months or 1 year post-hospitalization. Late gadolinium enhancement was present in 2 (0.8%) patients, 1 at 3 months and another at 6 months following hospitalization. Coronary artery dilation was present in 13 of the 174 (7.5%) patients. Nine patients met the Lake Louise criteria for myocarditis (3.5%) at the time of CMR.

CONCLUSIONS

In this largest published multiinstitutional longitudinal CMR evaluation of confirmed Multisystem Inflammatory Syndrome in Children patients, the prevalence of ventricular dysfunction and myocardial tissue characterization abnormalities on medium-term follow-up was low. However, a small number of patients had mild residual abnormalities at 6 months and 1 year following hospitalization.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT05287412.

Six-Month Outcomes in the Long-Term Outcomes After the Multisystem Inflammatory Syndrome in Children Study

Importance

Multisystem inflammatory syndrome in children (MIS-C) is a life-threatening complication of COVID-19 infection. Data on midterm outcomes are limited.

Objective

To characterize the frequency and time course of cardiac dysfunction (left ventricular ejection fraction [LVEF] <55%), coronary artery aneurysms (z score ≥2.5), and noncardiac involvement through 6 months after MIS-C.

Design, Setting, and Participants

This cohort study enrolled participants between March 2020 and January 2022 with a follow-up period of 2 years. Participants were recruited from 32 North American pediatric hospitals, and all participants met the 2020 Centers for Disease Control and Prevention case definition of MIS-C.

Exposure

MIS-C after COVID-19 infection.

Main Outcomes and Measures

Outcomes included echocardiography core laboratory (ECL) assessments of LVEF and maximum coronary artery z scores (zMax); data collection on cardiac and noncardiac sequelae during hospitalization and at 2 weeks, 6 weeks, and 6 months after discharge; and age-appropriate Patient-Reported Outcomes Measurement Information Systems (PROMIS) Global Health Instruments at follow-up. Descriptive statistics, linear regression models, and Kaplan-Meier analysis were used.

Results

Of 1204 participants (median [IQR] age, 9.1 [5.6-12.7] years; 724 male [60.1%]), 325 self-identified with non-Hispanic Black race (27.0%) and 324 with Hispanic ethnicity (26.9%). A total of 548 of 1195 participants (45.9%) required vasoactive support, 17 of 1195 (1.4%) required extracorporeal membrane oxygenation, and 3 (0.3%) died during hospitalization. Of participants with echocardiograms reviewed by the ECL (n = 349 due to budget constraints), 131 of 322 (42.3%) had LVEF less than 55% during hospitalization; of those with follow-up, all but 1 normalized by 6 months. Black race (vs other/unknown race), higher C-reactive protein level, and abnormal troponin level were associated with lowest LVEF (estimate [SE], -3.09 [0.98]; R2 = 0.14; P =.002). Fifteen participants had coronary artery z scores of 2.5 or greater at any time point; 1 participant had a large/giant aneurysm. Of the 13 participants with z scores of 2.5 or greater during hospitalization, 12 (92.3%) had normalized by 6 months. Return to greater than 90% of pre-MIS-C health status (energy, sleep, appetite, cognition, and mood) was reported by 711 of 824 participants (86.3%) at 2 weeks, increasing to 548 of 576 (95.1%) at 6 months. Fatigue was the most common symptom reported at 2 weeks (141 of 889 [15.9%]), falling to 3.4% (22 of 638) by 6 months. PROMIS Global Health parent/guardian proxy median T scores for fatigue, global health, and pain interference improved significantly from 2 weeks to 6 months (fatigue, 56.1 vs 48.9; global health, 48.8 vs 51.3; pain interference, 53.0 vs 43.3; P < .001) and by the 6-week visit were at least equivalent to prepandemic population norms.

Conclusions and Relevance

Results of this cohort study suggest that although children and young adults with MIS-C can have severe disease during the acute phase, most recovered quickly and had a reassuring midterm prognosis.

Immune Profile and MRI-Detected Cardiac Fibrosis and Edema in Hypertensive and Non-Hypertensive Patients with COVID-19

Cardiac involvement in 2019 coronavirus disease (COVID-19) survivors has been reported frequently. An exacerbated immune response may be the main mechanism of myocardial injury and late cardiac sequelae in this population. Background/Objectives: We investigated the immune profile in hypertensive and non-hypertensive patients with COVID-19 who developed late cardiac fibrosis and edema, as detected by magnetic resonance imaging (MRI). Methods: We evaluated associations of cytokine and immune-cell subset levels during hospitalization for COVID-19 with the presence of myocardial interstitial fibrosis [represented by the extracellular volume (ECV)] or edema (represented by the T2), detected by cardiac MRI examination after discharge, in hypertensive and non-hypertensive patients. Results: Patients with hypertension had reduced B-cell percentages, increased natural killer cell percentages, and higher interleukin (IL)-4, IL-5, IL-13, IL-17A, and tumor necrosis factor-β levels compared to patients without hypertension. Larger percentages of human leukocyte antigen DR isotope+ blood cells, reflecting CD8+ T-cell activation, correlated with increased T2 and ECV in hypertensive patients. The HLA-DR mean fluorescence intensity was associated with ECV in non-hypertensive patients. Conclusions: Our findings reveal cytokine and immune-cell dysregulation in both hypertensive and non-hypertensive patients with COVID-19, along with moderate correlations between CD8+ T-cell activation and increased cardiac MRI markers of myocardial interstitial fibrosis and edema. These results contribute to a deeper understanding of immune dysfunction mechanisms involved in myocardial remodeling.

Myocarditis in children 2024, new themes and continued questions

PURPOSE OF REVIEW

While pediatric myocarditis incidence has increased since the coronavirus disease 2019 (COVID-19) pandemic, there remain questions regarding diagnosis, risk stratification, and optimal therapy. This review highlights recent publications and continued unanswered questions related to myocarditis in children.

RECENT FINDINGS

Emergence from the COVID-19 era has allowed more accurate description of the incidence and prognosis of myocarditis adjacent to COVID-19 infection and vaccine administration as well that of multi-system inflammatory disease in children (MIS-C). As cardiac magnetic resonance technology has shown increased availability and evidence in pediatric myocarditis, it is important to understand conclusions from adult imaging studies and define the use of this imaging biomarker in children. Precision medicine has begun to allow real-time molecular evaluations to help diagnose and risk-stratify cardiovascular diseases, with emerging evidence of these modalities in myocarditis.

SUMMARY

Recent information regarding COVID-19 associated myocarditis, cardiac magnetic resonance, and molecular biomarkers may help clinicians caring for children with myocarditis and identify needs for future investigations.

Cardiovascular Follow-up of Patients Treated for MIS-C

OBJECTIVES

To assess the prevalence of residual cardiovascular pathology by cardiac MRI (CMR), ambulatory rhythm monitoring, and cardiopulmonary exercise testing (CPET) in patients ∼6 months after multisystem inflammatory disease in children (MIS-C).

METHODS

Patients seen for MIS-C follow-up were referred for CMR, ambulatory rhythm monitoring, and CPET ∼6 months after illness. Patients were included if they had ≥1 follow-up study performed by the time of data collection. MIS-C was diagnosed on the basis of the Centers for Disease Control and Prevention criteria. Myocardial injury during acute illness was defined as serum Troponin-I level >0.05 ng/mL or diminished left ventricular systolic function on echocardiogram.

RESULTS

Sixty-nine of 153 patients seen for MIS-C follow-up had ≥1 follow-up cardiac study between October 2020-June 2022. Thirty-seven (54%) had evidence of myocardial injury during acute illness. Of these, 12 of 26 (46%) had ≥1 abnormality on CMR, 4 of 33 (12%) had abnormal ambulatory rhythm monitor results, and 18 of 22 (82%) had reduced functional capacity on CPET. Of the 37 patients without apparent myocardial injury, 11 of 21 (52%) had ≥1 abnormality on CMR, 1 of 24 (4%) had an abnormal ambulatory rhythm monitor result, and 11 of 15 (73%) had reduced functional capacity on CPET. The prevalence of abnormal findings was not statistically significantly different between groups.

CONCLUSIONS

The high prevalence of abnormal findings on follow-up cardiac studies and lack of significant difference between patients with and without apparent myocardial injury during hospitalization suggests that all patients treated for MIS-C warrant cardiology follow-up.

Six-month cardiac outcomes in children with multisystem inflammatory syndrome in children

BACKGROUND

Multisystem inflammatory syndrome in children is a rare, post-infectious complication of SARS-CoV-2 infection in children. We aimed to assess the long-term sequelae, particularly cardiac, in a large, diverse population.

METHODS

We performed a retrospective cohort study of all children (aged 0-20 years, n = 304) admitted to a tertiary care centre with a diagnosis of multisystem inflammatory syndrome in children from March 1, 2020 to August 31, 2021 and had at least one follow-up visit through December 31, 2021. Data were collected at hospitalisation, 2 weeks, 6 weeks, 3 months, and 1 year after diagnosis, where applicable. Cardiovascular outcomes included left ventricular ejection fraction, presence or absence of pericardial effusion, coronary artery abnormalities, and abnormal electrocardiogram findings.

RESULTS

Population was median age 9 years (IQR 5-12), 62.2% male, 61.8% African American (AA), and 15.8% Hispanic. Hospitalisation findings included abnormal echocardiogram 57.2%, mean worst recorded left ventricular ejection fraction 52.4% ± 12.4%, non-trivial pericardial effusion 13.4%, coronary artery abnormalities 10.6%, and abnormal ECG 19.6%. During follow-up, abnormal echocardiogram significantly decreased to 6.0% at 2 weeks and 4.7% at 6 weeks. Mean left ventricular ejection fraction significantly increased to 65.4% ± 5.6% at 2 weeks and stabilised. Pericardial effusion significantly decreased to 3.2% at 2 weeks and stabilised. Coronary artery abnormalities significantly decreased to 2.0% and abnormal electrocardiograms significantly decreased to 6.4% at 2 weeks and stabilised.

CONCLUSION

Children with multisystem inflammatory syndrome in children have significant echocardiographic abnormalities during the acute presentation, but these findings typically improve within weeks. However, a small subset of patients may have persistent coronary abnormalities.

Exercise testing in patients with multisystem inflammatory syndrome in children-related myocarditis versus idiopathic or viral myocarditis

BACKGROUND

While most children with multisystem inflammatory syndrome in children have rapid recovery of cardiac dysfunction, little is known about the long-term outcomes regarding exercise capacity. We aimed to compare the exercise capacity among patients with multisystem inflammatory syndrome in children versus viral/idiopathic myocarditis at 3-6 months after initial diagnosis.

METHODS

We performed a retrospective cohort study among patients with multisystem inflammatory syndrome in children in June 2020 to May 2021 and patients with viral/idiopathic myocarditis in August 2014 to January 2020. Data from cardiopulmonary exercise test as well as echocardiographic and laboratory data were obtained. Inclusion criteria included diagnosis of multisystem inflammatory syndrome in children or viral/idiopathic myocarditis, exercise test performed within 3-6 months of hospital discharge, and maximal effort on cardiopulmonary exercise test as determined by respiratory exchange ratio >1.10.

RESULTS

Thirty-one patients with multisystem inflammatory syndrome in children and 25 with viral/idiopathic myocarditis were included. The mean percent predicted peak VO2 was 90.84% for multisystem inflammatory syndrome in children patients and 91.08% for those with viral/idiopathic myocarditis (p-value 0.955). There were no statistically significant differences between the groups with regard to percent predicted maximal heart rate, metabolic equivalents, percent predicted peak VO2, percent predicted anerobic threshold, or percent predicted O2 pulse. There was a statistically significant correlation between lowest ejection fraction during hospitalisation and peak VO2 among viral/idiopathic myocarditis patients (r: 0.62, p-value 0.01) but not multisystem inflammatory syndrome in children patients (r: 0.1, p-value 0.6).

CONCLUSIONS

Patients with multisystem inflammatory syndrome in children and viral myocarditis appear to, on average, have normal exercise capacity around 3-6 months following hospital discharge. For patients with viral/idiopathic myocarditis, those with worse ejection fraction during hospitalisation had lower peak VO2 on cardiopulmonary exercise test.

Three-Dimensional Echocardiography and Global Longitudinal Strain in Follow-Up After Multisystem Inflammatory Syndrome in Children: Six-Month, Single-Center, Prospective Study

OBJECTIVE

To assess the potential long-term cardiac effects after multisystem inflammatory syndrome in children (MIS-C) with cardiovascular involvement in the acute phase.

STUDY DESIGN

Our prospective study involved children consecutively diagnosed with MIS-C between October 2020 and February 2022 and followed 6 weeks and 6 months after the disease. In patients with severe cardiac involvement during the acute phase, an additional check-up after 3 months was scheduled. In all patients at all check-ups, 3-dimensional echocardiography and global longitudinal strain (GLS) were used to assess ventricular function.

RESULTS

The study enrolled 172 children aged 1-17 years (median, 8 years). The means of ejection fraction (EF) and GLS for both ventricles were within normal limits after 6 weeks with no relationship with initial severity: left ventricular EF (LVEF) 60% (59%-63%), LV GLS -21.08% (-18.63% to -23.2%), right ventricular (RV) EF 64% (62%-67%), and RV GLS -22.8% (-20.5% to -24.5%). Further, statistically significant improvement of LV function was observed after 6 months-LVEF 63% (62%-65%) and LV GLS -22.55% (-21.05% to -24.25%; P < .05); however, RV function remained unchanged. The group with severe cardiac involvement showed LV function recovery pattern with no significant improvement between 6 weeks and 3 months after MIS-C, while still improving between 3 and 6 months after discharge.

CONCLUSIONS

LV and RV function is within normal limits 6 weeks after MIS-C regardless of severity of cardiovascular involvement; LV function improves further between 6 weeks and 6 months after the disease. The long-term prognosis is optimistic with full recovery of cardiac function.

Imaging Acute and Chronic Cardiac Complications of COVID-19 and after COVID-19 Vaccination

COVID-19 is associated with acute and longer-term cardiovascular manifestations including myocardial injury, myopericarditis, stress-induced cardiomyopathy, myocardial infarction, and thromboembolic disease. Although the morbidity and mortality related to acute COVID-19 have decreased substantially, there is growing concern about the longer-term cardiovascular effects of the disease and postacute sequelae. Myocarditis has also been reported after messenger ribonucleic acid (mRNA)-based COVID-19 vaccination, with the highest risk among adolescent boys and young adult men. Noninvasive imaging including cardiac MRI has a key role in identifying the presence of cardiovascular disease, evaluating for potential mechanisms of injury, stratifying risk of future adverse cardiovascular events, and potentially guiding treatment in patients with suspected cardiovascular injury after COVID-19 and vaccination. Patterns of injury identified at cardiac MRI after COVID-19 include myocarditis and pericarditis, myocardial ischemia, and infarction. Myocardial edema and late gadolinium enhancement have been described months after the initial infection in a minority of patients with persistent cardiac symptoms after COVID-19. In patients with myocarditis after receiving a COVID-19 vaccination, the most common pattern of late gadolinium enhancement is subepicardial at the basal inferolateral wall, and patients tend to have milder imaging abnormalities compared with those from other causes of myocarditis. This article describes the role of multimodality cardiac imaging and imaging findings in patients with acute and longer-term cardiovascular manifestations of COVID-19 and in patients with myocarditis after receiving an mRNA-based COVID-19 vaccination. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Short- and mid-term outcomes of multisystem inflammatory syndrome in children: a longitudinal prospective single-center cohort study

Background

Multisystem inflammatory syndrome in children (MIS-c) emerged during the coronavirus disease 2019 pandemic and is associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Despite the extensively studied clinical manifestation of acute condition, the short- and long-term effects of MIS-c on children's health are unknown.

Methods

This was a prospective longitudinal cohort study. Children aged <18 years who met the Centers for Disease Prevention and Control (CDC) diagnostic criteria and who were admitted to the Children's Clinical University Hospital of Latvia (CCUH) between July 1, 2020, and April 15, 2022, were enrolled in the study. An outpatient follow-up program was initiated in July 2020. All children were evaluated at 2 weeks, 2 months (1-3 months), and 6 months (5-7 months) after discharge. The face-to-face interviews comprised four domains as follows: symptom assessment, physical examination, laboratory testing, and cardiological investigation [including electrocardiogram (ECG) and echocardiography (echo)].

Results

Overall, 21 patients with MIS-c were enrolled. The median age of the study group was 6 years. At the 2-week follow-up, almost half of the patients (N = 10, 47.6%) reported exercise intolerance with provoked tiredness. Laboratory tests showed a considerable increase in blood cell count, with a near doubling of leukocyte and neutrophil counts and a tripling of thrombocyte levels. However, a decline in the levels of inflammatory and organ-specific markers was observed. Cardiological investigation showed significant improvement with gradual resolution of the acute-phase pathological findings. Within 2 months, improvement in exercise capacity was observed with 5-fold and 2-fold reductions in physical intolerance (N = 2, 9.5%) and physical activity-induced fatigue (N = 5, 23.8%), respectively. Normalization of all blood cell lines was observed, and cardiological investigation showed no persistent changes. At the 6-month visit, further improvement in the children's exercise capacity was observed, and both laboratory and cardiological investigation showed no pathological changes.

Conclusions

Most persistent symptoms were reported within the first 2 weeks after the acute phase, with decreased physical activity tolerance and activity-induced fatigue as the main features. A positive trend was observed at each follow-up visit as the spectrum of the children's complaints decreased. Furthermore, rapid normalization of laboratory markers and cardiac abnormalities was observed.

Emerging Insights Into the Pathophysiology of Multisystem Inflammatory Syndrome Associated With COVID-19 in Children

Multisystem inflammatory syndrome in children (MIS-C) has emerged as a rare delayed hyperinflammatory response to SARS-CoV-2 infection and causes severe morbidity in the pediatric age group. Although MIS-C shares many clinical similarities to Kawasaki disease (KD), important differences in epidemiologic, clinical, immunologic, and potentially genetic factors exist and suggest potential differences in pathophysiology and points to be explored and explained. Epidemiologic features include male predominance, peak age of 6 to12 years, and specific racial or ethnicity predilections. MIS-C is characterized by fever, prominent gastrointestinal symptoms, mucocutaneous manifestations, respiratory symptoms, and neurologic complaints, and patients often present with shock. Cardiac complications are frequent and include ventricular dysfunction, valvular regurgitation, pericardial effusion, coronary artery dilation and aneurysms, conduction abnormalities, and arrhythmias. Emerging evidence regarding potential immunologic mechanisms suggest that an exaggerated T-cell response to a superantigen on the SARS-CoV-2 spike glycoprotein-as well as the formation of autoantibodies against cardiovascular, gastrointestinal, and endothelial antigens-are major contributors to the inflammatory milieu of MIS-C. Further studies are needed to determine both shared and distinct immunologic pathway(s) that underlie the pathogenesis of MIS-C vs both acute SARS-CoV-2 infection and KD. There is evidence to suggest that the rare risk of more benign mRNA vaccine-associated myopericarditis is outweighed by a reduced risk of more severe MIS-C. In the current review, we synthesize the published literature to describe associated factors and potential mechanisms regarding an increased risk of MIS-C and cardiac complications, provide insights into the underlying immunologic pathophysiology, and define similarities and differences with KD.

Cardiac Involvement in Patients with Multisystem Inflammatory Syndrome in Children (MIS-C) in Poland

Multisystem inflammatory syndrome in children (MIS-C) is an immune-mediated complication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Cardiovascular system is commonly involved. Acute heart failure (AHF) is the most severe complication of MIS-C, leading to cardiogenic shock. The aim of the study was to characterise the course of MIS-C with a focus on cardiovascular involvement, based on echocardiographic (echo) evaluation, in 498 children (median age 8.3 years, 63% boys) hospitalised in 50 cities in Poland. Among them, 456 (91.5%) had cardiovascular system involvement: 190 (48.2%) of patients had (most commonly atrioventricular) valvular insufficiency, 155 (41.0%) had contractility abnormalities and 132 (35.6%) had decreased left ventricular ejection fraction (LVEF < 55%). Most of these abnormalities improved within a few days. Analysis of the results obtained from two echo descriptions (a median of 5 days apart) revealed a >10% increase in LVEF even in children with primarily normal LVEF. Lower levels of lymphocytes, platelets and sodium and higher levels of inflammatory markers on admission were significantly more common among older children with contractility dysfunction, while younger children developed coronary artery abnormality (CAA) more often. The incidence of ventricular dysfunction might be underestimated. The majority of children with AHF improved significantly within a few days. CAAs were relatively rare. Children with impaired contractility as well as other cardiac abnormalities differed significantly from children without such conditions. Due to the exploratory nature of this study, these findings should be confirmed in further studies.

Long-Term Cardiovascular Outcomes of Multisystem Inflammatory Syndrome in Children Associated with COVID-19 Using an Institution Based Algorithm

Cardiovascular involvement is a major cause of inpatient and intensive care unit morbidity related to Multisystem inflammatory syndrome in children (MIS-C). The objective of this study was to identify long-term cardiovascular manifestations of MIS-C. We included 80 consecutive patients admitted to the intensive care unit with MIS-C who were evaluated for a year in our follow-up clinic using an institution protocol. The outcome measures were cardiac biomarkers (troponin and BNP), electrocardiogram changes, echocardiographic findings cardiovascular magnetic resonance (CMR) and graded-exercise stress test (GXT) findings. The cohort included patients aged between 6 months and 17 years (median 9 years; 48.8% females). At the peak of the disease 81.3% had abnormal BNP and 58.8% had troponin leak which reduced to 33.8% and 18.8% respectively at discharge with complete normalization by 6 weeks post-discharge. At admission 33.8% had systolic dysfunction, which improved to 11.3% at discharge with complete resolution by 2 weeks. Coronary artery abnormalities were seen in 17.5% during the illness with complete resolution by 2 weeks post discharge except one (1.9%) with persistent giant aneurysm at 1 year-follow up. CMR was performed at 6 months in 23 patient and demonstrated 4 patients with persistent late gadolinium enhancement (17.4%). Normal exercise capacity with no ectopy was seen in the 31 qualifying patients that underwent a GXT. There is significant heterogeneity in the cardiovascular manifestations of MIS-C. Although majority of the cardiovascular manifestations resolve within 6 weeks, diastolic dysfunction, CAA and myocardial scar may persist in a small subset of patients warranting a structured long-term follow-up strategy.

The First Case in Japan of Fulminant Myocarditis Due to Multisystem Inflammatory Syndrome in Children (MIS-C) That Required Mechanical Circulatory Support

Multisystem inflammatory syndrome in children (MIS-C) is a novel hyperinflammatory syndrome that is associated with severe acute respiratory syndrome coronavirus 2 infections. Reports describing the mechanical circulatory support (MCS) and myocardial biopsy for fulminant myocarditis due to MIS-C are limited.A 13-year-old male patient with MIS-C underwent treatment, including immunosuppressive therapy and MCS devices, and managed to recover from pulseless electrical activity cardiac arrest.This is the first patient in Japan with MIS-C who required MCS devices in Japan. Appropriate and immediate treatment with immunosuppressive therapy and MCS devices is important.

Cardiac Assessment in Children with MIS-C: Late Magnetic Resonance Imaging Features

Multisystem Inflammatory Syndrome (MIS-C) is a new entity that emerges 2-4 weeks after the SARS-CoV-2 infection in children. MIS-C can affect all systems, the most severe of which is cardiac involvement. The duration of the cardiac symptoms is still uncertain and may be persistent or prolonged. The American College of Rheumatology Clinical Guidelines recommends cardiac magnetic resonance imaging (MRI) 2-6 months after the diagnosis of MIS-C in patients presenting with significant transient left ventricular (LV) dysfunction in the acute phase of illness (LV ejection fraction 50%) or persistent LV dysfunction. There are a few studies investigating cardiac MRI findings in MIS-C patients. In this study, we aimed to evaluate cardiac MRI findings, at the earliest 3 months after diagnosis, and compare these findings with the echocardiograms in children with MIS-C. A retrospective study including 34 MIS-C patients was conducted at a tertiary-level University Hospital between June 2020 and July 2021. Centers for Disease Control and Prevention criteria were used in the diagnosis of MIS-C. Cardiac MRI was performed at least 3 months after MIS-C diagnosis. The study included 17 (50%) boys and 17 (50%) girls with a mean age of 9.31 ± 4.72 years. Initial echocardiographic evaluation revealed cardiac abnormality in 13 (38.2) patients; 4 (11.8%) pericardial effusion, 4 (11.8%) left ventricular ejection fraction (LVEF) < 55%, and 5 (14.7%) coronary artery dilatation. Echocardiography showed normal LV systolic function in all patients during follow-up; coronary dilatation persisted in 2 of 5 (40%) patients at the 6th-month visit. Cardiac MRI was performed in 31 (91.2%) patients, and myocardial hyperemia was not detected in any patients (T1 relaxation time was < 1044 ms in all children). However, 9 (29%) patients' MRI showed isolated elevated T2 levels, and 19 (61.3%) revealed at least one of the following findings: pericardial effusion, right ventricular dysfunction, or LVEF abnormality. In patients with MIS-C, a high rate of cardiac involvement, particularly pericardial effusion was determined by cardiac MRI performed at the earliest 2-6 months after diagnosis. Even if echocardiography does not reveal any abnormality in the initial phase, cardiac MRI should be suggested in MIS-C patients in the late period. This is the first study reporting cardiac MRI findings in the late period of MIS-C patients.

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.

Age-adjusted NT-proBNP could help in the early identification and follow-up of children at risk for severe multisystem inflammatory syndrome associated with COVID-19 (MIS-C)

BACKGROUND

Multisystem inflammatory syndrome in children (MIS-C) has emerged as a new disease associated with COVID-19 that presents in acute critically ill children with acute cardiovascular dysfunction.

AIM

To determine whether the age-adjusted N-terminal pro-brain natriuretic peptide (NT-proBNP) value (Z-log-NT-proBNP) is associated with severe MIS-C and myocardial dysfunction.

METHODS

A retrospective study was conducted which included children with MIS-C managed at our institution between April 1, 2020, and February 28, 2022. We divided the population into groups depending on severity based on pediatric intensive care unit (PICU) admission. We compared Z-log-NT-proBNP values across these groups and analyzed Z-log-NT-proBNP dynamics during the one-month follow-up.

RESULTS

We included 17 participants [median age 3 (2-9) years] and seven (41%) required PICU admission. All (100%) of these cases presented very high (Z-log > 4) levels of NT-proBNP at the time of admission compared to only 5 (50%) patients with non-severe MIS-C (P = 0.025). NT-proBNP was significantly correlated with high-sensitive Troponin I levels (P = 0.045), Ross modified score (P = 0.003) and left ventricle ejection fraction (P = 0.021).

CONCLUSION

Raised NT-proBNP, specifically very high values (Z-log-NT-proBNP > 4) could help in the early identification of MIS-C patients with myocardial dysfunction requiring inotropic support and PICU admission.