Left Atrial Strain in Multisystem Inflammatory Syndrome in Children and Associations with Systemic Inflammation and Cardiac Injury.

Multisystem inflammatory syndrome in children (MIS-C) commonly involves cardiac injury with both systolic and diastolic dysfunction. Left atrial strain (LAS) detects subclinical diastolic dysfunction in adults but is infrequently used in children. We evaluated LAS in MIS-C and the associations with systemic inflammation and cardiac injury. In this retrospective cohort study, LAS parameters [reservoir (LAS-r), conduit (LAS-cd), and contractile (LAS-ct)] obtained from admission echocardiograms of MIS-C patients were compared to healthy controls and between MIS-C patients with and without cardiac injury (BNP > 500 pg/ml or troponin-I > 0.04 ng/ml). Correlation and logistic regression analyses were performed to assess LAS associations with admission inflammatory and cardiac biomarkers. Reliability testing was performed. We identified 118 patients with MIS-C and 20 healthy controls. Median LAS parameters were reduced in MIS-C patients compared to controls (LAS-r: 31.8 vs. 43.1%, p < 0.001; LAS-cd: - 28.8 vs. - 34.5%, p = 0.006; LAS-ct: - 5.2 vs. - 9.3%, p < 0.001) and reduced in MIS-C patients with cardiac injury (n = 59) compared to no injury (n = 59) (LAS-r: 29.6 vs. 35.8%, p = 0.001; LAS-cd: - 26.5 vs. - 30.4%, p = 0.036; LAS-ct: - 4.6 vs. - 9.3%, p = 0.008). A discrete LAS-ct peak was absent in 65 (55%) MIS-C patients but present in all controls (p < 0.001). Procalcitonin correlated strongly with averaged E/e' (r = 0.55, p = 0.001). Moderate correlations were found for ESR and LAS-ct (r = - 0.41, p = 0.007) as well as BNP and LAS-r (r = - 0.39, p < 0.001) and LAS-ct (r = 0.31, p = 0.023). Troponin-I had only weak correlations. Intra-rater reliability was good for all LAS parameters, and inter-rater reliability was good to excellent for LAS-r, and fair for LAS-cd and LAS-ct. LAS analysis, particularly the absence of a LAS-ct peak, was reproducible and may be superior to conventional echocardiographic parameters for detecting diastolic dysfunction in MIS-C. No strain parameters on admission were independently associated with cardiac injury.

Clinically Suspected Myocarditis Temporally Related to COVID-19 Vaccination in Adolescents and Young Adults: Suspected Myocarditis After COVID-19 Vaccination.

BACKGROUND: Understanding the clinical course and short-term outcomes of suspected myocarditis after the coronavirus disease 2019 (COVID-19) vaccination has important public health implications in the decision to vaccinate youth. METHODS: We retrospectively collected data on patients <21 years old presenting before July 4, 2021, with suspected myocarditis within 30 days of COVID-19 vaccination. Lake Louise criteria were used for cardiac MRI findings. Myocarditis cases were classified as confirmed or probable on the basis of the Centers for Disease Control and Prevention definitions. RESULTS: We report on 139 adolescents and young adults with 140 episodes of suspected myocarditis (49 confirmed, 91 probable) at 26 centers. Most patients were male (n=126, 90.6%) and White (n=92, 66.2%); 29 (20.9%) were Hispanic; and the median age was 15.8 years (range, 12.1-20.3; interquartile range [IQR], 14.5-17.0). Suspected myocarditis occurred in 136 patients (97.8%) after the mRNA vaccine, with 131 (94.2%) after the Pfizer-BioNTech vaccine; 128 (91.4%) occurred after the second dose. Symptoms started at a median of 2 days (range, 0-22; IQR, 1-3) after vaccination. The most common symptom was chest pain (99.3%). Patients were treated with nonsteroidal anti-inflammatory drugs (81.3%), intravenous immunoglobulin (21.6%), glucocorticoids (21.6%), colchicine (7.9%), or no anti-inflammatory therapies (8.6%). Twenty-six patients (18.7%) were in the intensive care unit, 2 were treated with inotropic/vasoactive support, and none required extracorporeal membrane oxygenation or died. Median hospital stay was 2 days (range, 0-10; IQR, 2-3). All patients had elevated troponin I (n=111, 8.12 ng/mL; IQR, 3.50-15.90) or T (n=28, 0.61 ng/mL; IQR, 0.25-1.30); 69.8% had abnormal ECGs and arrhythmias (7 with nonsustained ventricular tachycardia); and 18.7% had left ventricular ejection fraction <55% on echocardiogram. Of 97 patients who underwent cardiac MRI at a median 5 days (range, 0-88; IQR, 3-17) from symptom onset, 75 (77.3%) had abnormal findings: 74 (76.3%) had late gadolinium enhancement, 54 (55.7%) had myocardial edema, and 49 (50.5%) met Lake Louise criteria. Among 26 patients with left ventricular ejection fraction <55% on echocardiogram, all with follow-up had normalized function (n=25). CONCLUSIONS: Most cases of suspected COVID-19 vaccine myocarditis occurring in persons <21 years have a mild clinical course with rapid resolution of symptoms. Abnormal findings on cardiac MRI were frequent. Future studies should evaluate risk factors, mechanisms, and long-term outcomes.

Pediatric Heart Network Trial of Losartan vs. Atenolol in Children and Young Adults with Marfan Syndrome: Impact on Prescription Practices.

The Pediatric Heart Network (PHN) trial showed similar efficacy of ß-blockers (BB) and angiotensin receptor blockers (ARB) for aortic root dilation in Marfan syndrome, but the impact on prescription practices is unknown. We hypothesized BB and ARB prescriptions would increase after the trial results were published (2014). Prescription data (2007-2016) were obtained from outpatient encounters (IBM Marketscan) for Marfan syndrome patients (6 months-25 years old). Excluding 2014 as a washout period, we analyzed two intervals: 2007-2013 and 2015-2016. Medication categories included BB, ARB, angiotensin converting enzyme inhibitors (ACEI), combination (BB/ARB and/or BB/ACEI), and no drug. Interrupted time-series analysis assessed immediate level change after publication and change in slope for the trend pre- and post-publication. Odds ratios (OR) and 95% confidence intervals from logistic regressions and generalized estimating equation methods accounted for correlation of prescriptions within patients. In 1499 patients (age 14.1 ± 6.1 years, 59% female) seen 2007-2013, BB trended lower [OR 0.91 (0.89, 0.93), p < 0.001] and ARB trended higher [OR 1.12 (1.07, 1.18), p < 0.001], while combination, ACEI, and no drug remained stable. This trend persisted, but was not significant, for BB [OR 0.54 (0.27, 1.08), p = 0.37] and ARB [OR 1.91 (0.55, 6.69), p = 0.31] in 2015-2016. Combination, ACEI, and no drug remained similar. In short term follow-up, changes in prescription practices following publication of the PHN trial were not statistically significant. This may be due to a change seen prior to publication with early adoption of ARBs that was maintained after confirmation of their effectiveness.

Cardiac Biomarkers Aid in Differentiation of Kawasaki Disease from Multisystem Inflammatory Syndrome in Children Associated with COVID-19.

Kawasaki disease (KD) and Multisystem Inflammatory Syndrome in Children (MIS-C) associated with COVID-19 show clinical overlap and both lack definitive diagnostic testing, making differentiation challenging. We sought to determine how cardiac biomarkers might differentiate KD from MIS-C. The International Kawasaki Disease Registry enrolled contemporaneous KD and MIS-C pediatric patients from 42 sites from January 2020 through June 2022. The study population included 118 KD patients who met American Heart Association KD criteria and compared them to 946 MIS-C patients who met 2020 Centers for Disease Control and Prevention case definition. All included patients had at least one measurement of amino-terminal prohormone brain natriuretic peptide (NTproBNP) or cardiac troponin I (TnI), and echocardiography. Regression analyses were used to determine associations between cardiac biomarker levels, diagnosis, and cardiac involvement. Higher NTproBNP (≥ 1500 ng/L) and TnI (≥ 20 ng/L) at presentation were associated with MIS-C versus KD with specificity of 77 and 89%, respectively. Higher biomarker levels were associated with shock and intensive care unit admission; higher NTproBNP was associated with longer hospital length of stay. Lower left ventricular ejection fraction, more pronounced for MIS-C, was also associated with higher biomarker levels. Coronary artery involvement was not associated with either biomarker. Higher NTproBNP and TnI levels are suggestive of MIS-C versus KD and may be clinically useful in their differentiation. Consideration might be given to their inclusion in the routine evaluation of both conditions.

The NHLBI Study on Long-terM OUtcomes after the Multisystem Inflammatory Syndrome In Children (MUSIC): Design and Objectives.

BACKGROUND: The Long-terM OUtcomes after the Multisystem Inflammatory Syndrome In Children (MUSIC) study aims to characterize the frequency and time course of acute and long-term cardiac and non-cardiac sequelae in multisystem inflammatory syndrome in children associated with COVID-19 (MIS-C), which are currently poorly understood. METHODS: This multicenter observational cohort study will enroll at least 600 patients <21 years old who meet the Centers for Disease Control and Prevention case definition of MIS-C across multiple North American centers over 2 years. The study will collect detailed hospital and follow-up data for up to 5 years, and optional genetic testing. Cardiac imaging at specific time points includes standardized echocardiographic assessment (all participants) and cardiac magnetic resonance imaging (CMR) in those with left ventricular ejection fraction (LVEF) <45% during the acute illness. The primary outcomes are the worst LVEF and the highest coronary artery z-score of the left anterior descending or right coronary artery. Other outcomes include occurrence and course of non-cardiac organ dysfunction, inflammation, and major medical events. Independent adjudication of cases will classify participants as definite, possible, or not MIS-C. Analysis of the outcomes will include descriptive statistics and regression analysis with stratification by definite or possible MIS-C. The MUSIC study will provide phenotypic data to support basic and translational research studies. CONCLUSION: The MUSIC study, with the largest cohort of MIS-C patients and the longest follow-up period to date, will make an important contribution to our understanding of the acute cardiac and non-cardiac manifestations of MIS-C and the long-term effects of this public health emergency.

The impact of the American Heart Association guidelines on patients treated for incomplete Kawasaki disease.

OBJECTIVES: To compare patients treated for incomplete Kawasaki disease whose practitioners followed versus did not follow American Heart Association criteria and to evaluate the association of cardiology consultation with adherence to these guidelines. STUDY DESIGN: Single centre retrospective cohort study of patients <18 years old who received ≥1 dose of intravenous immunoglobulin for Kawasaki disease between 01/2006 and 01/2018. We collected demographics, clinical and laboratory data, coronary artery abnormalities, and cardiology consultation status. Patients treated for incomplete Kawasaki disease were divided into two groups based on adherence versus nonadherence to American Heart Association guidelines and compared by Wilcoxon rank sum test and chi-squared or Fisher's exact test. RESULTS: Of the 357 patients treated for Kawasaki disease, 109 (31%) were classified as incomplete Kawasaki disease. The American Heart Association algorithm for identifying patients with incomplete Kawasaki disease was followed in 81/109 (74%). Coronary artery abnormalities were present in 46/109 (42%) of the patients who were treated for incomplete Kawasaki disease. Cardiology consultation was more frequent in those fulfilling American Heart Association criteria for the diagnosis of incomplete Kawasaki disease versus those who did not fulfill criteria (76% versus 48%, p = 0.005). CONCLUSIONS: Over 25% of patients treated for incomplete Kawasaki disease did not meet American Heart Association guidelines. Guidelines were more frequently followed when the paediatric cardiology team was consulted. Consulting physicians with experience and expertise in the evaluation and management of incomplete KD should be strongly considered in the care of these patients.

Poor Weight Recovery Between Stage 1 Palliation and Hospital Discharge for Infants with Single Ventricle Physiology: An Analysis of the National Pediatric Cardiology Quality Improvement Collaborative Phase II Dataset.

OBJECTIVE: To investigate change in weight-for-age z-scores (WAZ) and risk factors for impaired weight gain between stage 1 palliation (S1P) for single ventricle physiology and discharge. STUDY DESIGN: This was a secondary analysis of the National Pediatric Cardiology Quality Improvement Collaborative Phase II database. The primary outcome was change in WAZ between S1P and discharge. Risk factors were selected using multivariable mixed effects regression constructed by step-wise model selection, with adjustment for WAZ at S1P and a random effect for center. RESULTS: Of 730 infants who were discharged after S1P, WAZ decreased in 98.6% (-1.5 ± 0.7). WAZ at discharge was <-1 but >-2 (at risk) in 40% and <-2 (failure to thrive) in 35% of participants. Males, higher WAZ at S1P, non-S1P procedures (mostly noncardiac), increased length of stay, necrotizing enterocolitis, and angiotensin-converting enzyme inhibitor use at discharge were associated with a greater decrease in WAZ. Preoperative enteral feeding and respiratory medications were associated with a lesser decrease in the WAZ. CONCLUSIONS: Nearly all infants lose weight after S1P with little recovery by hospital discharge. At discharge, three-quarters of the infants in the cohort were at risk for impaired weight gain or had failure to thrive. Most risk factors associated with change in WAZ were unmodifiable or surrogates of disease severity. Novel interventions are needed to minimize the early catabolic effects and promote anabolic recovery after S1P.

Implications of Changing Z-Score Models for Coronary Artery Dimensions in Kawasaki Disease.

BACKGROUND: Coronary artery abnormalities in Kawasaki disease (KD) are assessed using echocardiographic z-scores. We hypothesized that changing the coronary artery (CA) z-score model would alter diagnosis and management of children with KD. METHODS: In this retrospective single-center study of children treated for KD (9/2007-1/2020), we collected echocardiographic measurements for the left anterior descending (LAD), right (RCA), and left main (LMCA) coronary arteries during 3 illness phases and calculated Boston and Pediatric Heart Network (PHN) z-scores. Agreement between Boston and PHN z-scores was assessed using Kappa (κ) and Lin's Concordance Correlation Coefficients (CCC) and Bland-Altman analysis. RESULTS: For 904 echocardiograms from 357 children, the median Boston LAD z-score was lower than the PHN (0.3 [IQR - 0.6, 1.5] vs 1.6 [IQR 0.7, 2.8], CCC 0.94 [95% CI 0.93, 0.95], moderate agreement), aggregated across all illness phases. RCA and LMCA z-scores showed substantial agreement. With conversion from Boston to PHN models, the percentage of individual LAD z-scores ≥ 2.5 increased (14.6% to 32.1%). At least one CA z-score classification changed in 213 children (59.7%) across all phases, and 48 children (13.4%) had a change that altered recommended antithrombotic strategy. Agreement between models differed by age, sex, and race. CONCLUSIONS: Conversion from Boston to PHN z-scores changed at least 1 CA z-score classification in over half of KD patients and changed recommended antithrombotic management in 13%, largely driven by LAD measurements. Since diagnosis and management of KD and KD-like diseases rely upon CA z-scores, the clinical and research implications of these findings merit further exploration.

Implications of Left Ventricular Dysfunction at Presentation for Infants with Coarctation of the Aorta.

Infants with aortic coarctation may present with left ventricular (LV) dysfunction which may complicate the postoperative course and lead to increased healthcare costs. We aimed to define the prevalence of moderate to severe left ventricular (LV) systolic dysfunction, evaluate time to recovery, and compare health care costs. Single-center retrospective cohort study at a tertiary care hospital was conducted. Infants < 6 months old at diagnosis with aortic coarctation were identified using surgical codes for coarctation repair between January 2010 and May 2018. Moderate to severe dysfunction was defined as ejection fraction (EF) < 40%. Of 160 infants studied, 18 (11%) had moderate to severe LV dysfunction at presentation. Compared to those with better LV function, infants with moderate to severe LV dysfunction were older at presentation (12 vs. 6 days, p = 0.004), had more postoperative cardiac intensive care unit (ICU) days (5 vs. 3, p < 0.001), and more ventilator days (3.5 vs. 1, p < 0.001). The median time to normal LV EF (≥ 55%) was 6 days postoperatively (range 1-230 days). Infants presenting with moderate to severe LV dysfunction had higher index hospitalization costs ($90,560 vs. $59,968, p = 0.02), but no difference in cost of medical follow-up for the first year following discharge ($3,078 vs. $2,568, p = 0.46). In the current era, > 10% of infants with coarctation present with moderate to severe LV dysfunction that typically recovers. Those with moderate to severe dysfunction had longer duration of mechanical ventilation and postoperative cardiac ICU stays, likely driving higher costs of index hospitalization.

Changes in Provider Prescribing Behavior for Infants with Single Ventricle Physiology After Evidence-Based Publications.

BACKGROUND: The impact of published evidence on clinical practice has been understudied in pediatric cardiology. OBJECTIVE: We sought to assess changes in prescribing behavior for angiotensin-converting enzyme inhibitor (ACEI) and digoxin at discharge after initial palliation of infants with single ventricle (SV) physiology following the publication of two large studies: The Pediatric Heart Network Infant Single Ventricle (PHN-ISV) trial showing no benefit with routine ACEI use and the National Pediatric Cardiology Quality Improvement Collaborative (NPC-QIC) analysis showing an association between digoxin and survival. METHODS: ICD-9-10 codes identified SV infants from the Pediatric Health Information System (1/2004 to 1/2018) and charge codes identified medications at discharge. Generalized estimating equations implementing segmented logistic regressions modeled medication use, before and after (with a 3-month washout period) the relevant publication (ACEI 7/1/2010; digoxin 4/1/2016). A subgroup analysis was performed for hypoplastic left heart syndrome (HLHS). RESULTS: ACEI use (37 centers, n = 4700) at discharge did not change over time during the pre-publication period. After publication of the PHN-ISV trial, ACEI use decreased (OR: 0.61, CI 0.44-0.84, p = 0.003). Digoxin use (43 centers, n = 4778) decreased by 1% monthly before publication. After the NPC-QIC publication, digoxin use increased (OR: 2.07, CI 1.05-4.08, p = 0.04) with an ongoing increase of 9% per month. Results were similar for the HLHS subgroup. CONCLUSIONS: Prescribing behavior changed congruently after the publication of evidence-based studies, with decreased ACEI use and increased digoxin use at discharge following initial palliation of SV infants. Our findings suggest scientific findings were rapidly implemented into clinical practice.

The association between feeding protocol compliance and weight gain following high-risk neonatal cardiac surgery.

BACKGROUND: Children with congenital heart disease are at high risk for malnutrition. Standardisation of feeding protocols has shown promise in decreasing some of this risk. With little standardisation between institutions' feeding protocols and no understanding of protocol adherence, it is important to analyse the efficacy of individual aspects of the protocols. METHODS: Adherence to and deviation from a feeding protocol in high-risk congenital heart disease patients between December 2015 and March 2017 were analysed. Associations between adherence to and deviation from the protocol and clinical outcomes were also assessed. The primary outcome was change in weight-for-age z score between time intervals. RESULTS: Increased adherence to and decreased deviation from individual instructions of a feeding protocol improves patients change in weight-for-age z score between birth and hospital discharge (p = 0.031). Secondary outcomes such as markers of clinical severity and nutritional delivery were not statistically different between groups with high or low adherence or deviation rates. CONCLUSIONS: High-risk feeding protocol adherence and fewer deviations are associated with weight gain independent of their influence on nutritional delivery and caloric intake. Future studies assessing the efficacy of feeding protocols should include the measures of adherence and deviations that are not merely limited to caloric delivery and illness severity.

Digoxin Use in Infants with Single Ventricle Physiology: Secondary Analysis of the Pediatric Heart Network Infant Single Ventricle Trial Public Use Dataset.

Digoxin has been associated with reduced interstage mortality after Norwood procedure. We sought to determine its association with survival and change in weight-for-age Z-score (WAZ) before the superior cavopulmonary connection (SCPC) surgery and at 14 months in a heterogeneous group of single ventricle infants. We performed a post-hoc analysis of the Pediatric Heart Network Infant Single Ventricle public use dataset to determine associations between digoxin and survival, transplant-free survival, and change in WAZ pre-SCPC and at 14 months. Sub-analyses of survival and transplant-free survival were performed for subjects who underwent Damus-Kaye-Stansel (DKS)/Norwood. Propensity score weighting was used in Cox hazard-proportion models. Of 229 subjects, 82 (36%) received digoxin and 147 (64%) received no digoxin. Pre-SCPC and 14-month survival and transplant-free survival were not significantly different between the digoxin and no digoxin groups for the main cohort and DKS/Norwood sub-group. However, in DKS/Norwood subjects there was a trend towards improved interstage transplant-free survival in the digoxin group (95.7 vs. 89.6%, p = 0.08). Digoxin was associated with a greater decrease in WAZ from birth to pre-SCPC (- 1.96 ± 0.19 vs. - 1.31 ± 0.18, p < 0.001) and birth to 14 months (- 0.64 ± 0.15 vs. - 0.19 ± 0.15, p = 0.03). Digoxin was not associated with improved survival during the interstage or at 14 months in a mixed single ventricle cohort, but there was a trend towards improved interstage transplant-free survival in post-Norwood infants. As digoxin was associated with poorer weight gain, further research is needed to identify the risks/benefits for anatomic subtypes of infants with single ventricles.

Platelet Inhibition in Shunted Infants on Aspirin at Short and Midterm Follow-Up.

There are few data to guide aspirin therapy to prevent shunt thrombosis in infants. We aimed to determine if aspirin administered at conventional dosing in shunted infants resulted in ≥50% arachidonic acid (AA) inhibition in short and midterm follow-up using thromboelastography with platelet mapping (TEG-PM) and to describe bleeding and thrombotic events during follow-up. We performed a prospective observational study of infants on aspirin following Norwood procedure, aortopulmonary shunt alone, or cavopulmonary shunt surgery. We obtained TEG-PM preoperatively, after the third dose of aspirin, at the first postoperative clinic visit, and 2-8 months after surgery. The primary outcome was the proportion of subjects with ≥50% AA inhibition on aspirin. All bleeding and thrombotic events were collected. Of 24 infants analyzed, 13% had ≥50% AA inhibition at all designated time points after aspirin initiation; 38% had ≥50% AA inhibition after the third aspirin dose of aspirin, 60% at the first postoperative clinic visit, and 26% 2-8 months after surgery. Bleeding events occurred in eight subjects, and two had a thrombotic event. Bleeding events were associated with greater AA inhibition just prior to starting aspirin (p = 0.02) and after the third dose of aspirin (p = 0.04), and greater ADP inhibition before surgery (p = 0.03). The majority of infants failed to consistently have ≥50% AA inhibition when checked longitudinally postoperatively. Preoperative TEG-PM may be useful in identifying infants at higher risk of bleeding events on aspirin in the early postoperative period. Further research is needed to guide antiplatelet therapy in this population.

Factors associated with recoarctation after surgical repair of coarctation of the aorta by way of thoracotomy in young infants.

Echocardiography is the mainstay of preoperative arch imaging in infants with coarctation of the aorta. In simple coarctation, repair by way of sternotomy or thoracotomy is often determined by echocardiographic transverse arch measurements. The degree of arch hypoplasia that is prohibitive to repair by way of thoracotomy is unknown. Clinical predictors of recoarctation are also unknown. Demographic, echocardiographic (transverse arch and aortic measurements), operative, and postoperative data of infants <90 days old with simple coarctation repaired by way of thoracotomy between February 2005 and November 2011 were evaluated. Recoarctation was defined as surgical or catheter reintervention after hospital discharge. Eighty-four infants underwent coarctation repair at median age of 12 (range 1-85) days with median follow-up of 12.3 (range 0.5-71.9) months. The seven (8 %) infants with recoarctation underwent balloon angioplasty. In multivariable analysis, only greater postoperative Doppler peak velocity [1.13, confidence interval (CI) 1.04-1.23] and greater sinotubular junction z-score (hazard ratio 4.19, CI 1.47-11.95) independently predicted coarctation. Doppler peak velocity >2.12 m/s had sensitivity of 63 % and specificity of 83 % of predicting recoarctation, and ST junction z-score >-0.93 had sensitivity of 100 % and specificity of 58 %. No transverse arch dimensions were independently associated with recoarctation. Infants with transverse arch z-score as low as -2.8 underwent successful repair by way of thoracotomy. No clinical predictors were significant.

Guidelines for Performing a Comprehensive Pediatric Transthoracic Echocardiogram: Recommendations From the American Society of Echocardiography.

Echocardiography is a fundamental component of pediatric cardiology, and appropriate indications have been established for its use in the setting of suspected, congenital, or acquired heart disease in children. Since the publication of guidelines for pediatric transthoracic echocardiography in 2006 and 2010, advances in knowledge and technology have expanded the scope of practice beyond the use of traditional modalities such as two-dimensional, M-mode, and Doppler echocardiography to evaluate the cardiac segmental structures and their function. Adjunct modalities such as contrast, three-dimensional, and speckle-tracking echocardiography are now used routinely at many pediatric centers. Guidelines and recommendations for the use of traditional and newer adjunct modalities in children are described in detail in this document. In addition, suggested protocols related to standard operations, infection control, sedation, and quality assurance and improvement are included to provide an organizational structure for centers performing pediatric transthoracic echocardiograms.

Kawasaki Disease in the Time of COVID-19 and MIS-C: The International Kawasaki Disease Registry.

BACKGROUND: Patients with multisystem inflammatory syndrome in children (MIS-C) and Kawasaki disease (KD) have overlapping clinical features. We compared demographics, clinical presentation, management, and outcomes of patients according to evidence of previous SARS-CoV-2 infection. METHODS: The International Kawasaki Disease Registry (IKDR) enrolled KD and MIS-C patients from sites in North, Central, and South America, Europe, Asia, and the Middle East. Evidence of previous infection was defined as: Positive (household contact or positive polymerase chain reaction [PCR]/serology), Possible (suggestive clinical features of MIS-C and/or KD with negative PCR or serology but not both), Negative (negative PCR and serology and no known exposure), and Unknown (incomplete testing and no known exposure). RESULTS: Of 2345 enrolled patients SARS-CoV-2 status was Positive for 1541 (66%) patients, Possible for 89 (4%), Negative for 404 (17%) and Unknown for 311 (13%). Clinical outcomes varied significantly among the groups, with more patients in the Positive/Possible groups presenting with shock, having admission to intensive care, receiving inotropic support, and having longer hospital stays. Regarding cardiac abnormalities, patients in the Positive/Possible groups had a higher prevalence of left ventricular dysfunction, and patients in the Negative and Unknown groups had more severe coronary artery abnormalities. CONCLUSIONS: There appears to be a spectrum of clinical features from MIS-C to KD with a great deal of heterogeneity, and one primary differentiating factor is evidence for previous acute SARS-CoV-2 infection/exposure. SARS-CoV-2 Positive/Possible patients had more severe presentations and required more intensive management, with a greater likelihood of ventricular dysfunction but less severe coronary artery adverse outcomes, in keeping with MIS-C.

Researching COVID to enhance recovery (RECOVER) pediatric study protocol: Rationale, objectives and design.

IMPORTANCE: The prevalence, pathophysiology, and long-term outcomes of COVID-19 (post-acute sequelae of SARS-CoV-2 [PASC] or "Long COVID") in children and young adults remain unknown. Studies must address the urgent need to define PASC, its mechanisms, and potential treatment targets in children and young adults. OBSERVATIONS: We describe the protocol for the Pediatric Observational Cohort Study of the NIH's REsearching COVID to Enhance Recovery (RECOVER) Initiative. RECOVER-Pediatrics is an observational meta-cohort study of caregiver-child pairs (birth through 17 years) and young adults (18 through 25 years), recruited from more than 100 sites across the US. This report focuses on two of four cohorts that comprise RECOVER-Pediatrics: 1) a de novo RECOVER prospective cohort of children and young adults with and without previous or current infection; and 2) an extant cohort derived from the Adolescent Brain Cognitive Development (ABCD) study (n = 10,000). The de novo cohort incorporates three tiers of data collection: 1) remote baseline assessments (Tier 1, n = 6000); 2) longitudinal follow-up for up to 4 years (Tier 2, n = 6000); and 3) a subset of participants, primarily the most severely affected by PASC, who will undergo deep phenotyping to explore PASC pathophysiology (Tier 3, n = 600). Youth enrolled in the ABCD study participate in Tier 1. The pediatric protocol was developed as a collaborative partnership of investigators, patients, researchers, clinicians, community partners, and federal partners, intentionally promoting inclusivity and diversity. The protocol is adaptive to facilitate responses to emerging science. CONCLUSIONS AND RELEVANCE: RECOVER-Pediatrics seeks to characterize the clinical course, underlying mechanisms, and long-term effects of PASC from birth through 25 years old. RECOVER-Pediatrics is designed to elucidate the epidemiology, four-year clinical course, and sociodemographic correlates of pediatric PASC. The data and biosamples will allow examination of mechanistic hypotheses and biomarkers, thus providing insights into potential therapeutic interventions. CLINICAL TRIALS.GOV IDENTIFIER: Clinical Trial Registration: http://www.clinicaltrials.gov. Unique identifier: NCT05172011.

Left atrial strain in multisystem inflammatory syndrome in children (MIS-C) and associations with systemic inflammation and cardiac injury.

Background: Multisystem inflammatory syndrome in children (MIS-C) commonly involves cardiac injury with both systolic and diastolic dysfunction. Left atrial strain (LAS) detects subclinical diastolic dysfunction in adults but is infrequently used in children. We evaluated LAS in MIS-C and the associations with systemic inflammation and cardiac injury. Methods: In this retrospective cohort study, conventional parameters and LAS (reservoir [LAS-r], conduit [LAS-cd], and contractile [LAS-ct]) obtained from admission echocardiograms of MIS-C patients were compared to healthy controls and between MIS-C patients with and without cardiac injury (BNP >500 pg/ml or troponin-I >0.04 ng/ml). Correlation and logistic regression analyses were performed to assess LAS associations with admission inflammatory and cardiac biomarkers. Reliability testing was performed. Results: Median LAS components were reduced in MIS-C patients (n=118) compared to controls (n=20) (LAS-r: 31.8 vs. 43.1%, p<0.001; LAS-cd: -28.8 vs. -34.5%, p=0.006; LAS-ct: -5.2 vs. -9.3%, p<0.001) and reduced in MIS-C patients with cardiac injury (n=59) compared to no injury (n=59) (LAS-r: 29.6 vs. 35.8%, p=0.001; LAS-cd: -26.5 vs. -30.4%, p=0.036; LAS-ct: -4.6 vs. -9.3%, p=0.008). An LAS-ct peak was absent in 65 (55%) MIS-C patients but present in all controls (p<0.001). Procalcitonin had strong correlation with averaged E/e' (r=0.55, p=0.001); ESR had moderate correlation with LAS-ct (r=-0.41, p=0.007); BNP had moderate correlation with LAS-r (r=-0.39, p<0.001) and LAS-ct (r=0.31, p=0.023), and troponin-I had only weak correlations. No strain indices were independently associated with cardiac injury on regression analysis. Intra-rater reliability was good for all LAS components; and inter-rater reliability was good to excellent for LAS-r, and fair for LAS-cd and LAS-ct. Conclusions: LAS analysis, particularly the absence of a LAS-ct peak, was reproducible and may be superior to conventional echocardiographic parameters for detecting diastolic dysfunction in MIS-C. No strain parameters on admission were independently associated with cardiac injury.

Obesity and Outcomes of Kawasaki Disease and COVID-19-Related Multisystem Inflammatory Syndrome in Children.

Importance: Obesity may affect the clinical course of Kawasaki disease (KD) in children and multisystem inflammatory syndrome in children (MIS-C) associated with COVID-19. Objective: To compare the prevalence of obesity and associations with clinical outcomes in patients with KD or MIS-C. Design, Setting, and Participants: In this cohort study, analysis of International Kawasaki Disease Registry (IKDR) data on contemporaneous patients was conducted between January 1, 2020, and July 31, 2022 (42 sites, 8 countries). Patients with MIS-C (defined by Centers for Disease Control and Prevention criteria) and patients with KD (defined by American Heart Association criteria) were included. Patients with KD who had evidence of a recent COVID-19 infection or missing or unknown COVID-19 status were excluded. Main Outcomes and Measures: Patient demographic characteristics, clinical features, disease course, and outcome variables were collected from the IKDR data set. Using body mass index (BMI)/weight z score percentile equivalents, patient weight was categorized as normal weight (BMI <85th percentile), overweight (BMI ≥85th to <95th percentile), and obese (BMI ≥95th percentile). The association between adiposity category and clinical features and outcomes was determined separately for KD and MIS-C patient groups. Results: Of 1767 children, 338 with KD (median age, 2.5 [IQR, 1.2-5.0] years; 60.4% male) and 1429 with MIS-C (median age, 8.7 [IQR, 5.3-12.4] years; 61.4% male) were contemporaneously included in the study. For patients with MIS-C vs KD, the prevalence of overweight (17.1% vs 11.5%) and obesity (23.7% vs 11.5%) was significantly higher (P < .001), with significantly higher adiposity z scores, even after adjustment for age, sex, and race and ethnicity. For patients with KD, apart from intensive care unit admission rate, adiposity category was not associated with laboratory test features or outcomes. For patients with MIS-C, higher adiposity category was associated with worse laboratory test values and outcomes, including a greater likelihood of shock, intensive care unit admission and inotrope requirement, and increased inflammatory markers, creatinine levels, and alanine aminotransferase levels. Adiposity category was not associated with coronary artery abnormalities for either MIS-C or KD. Conclusions and Relevance: In this international cohort study, obesity was more prevalent for patients with MIS-C vs KD, and associated with more severe presentation, laboratory test features, and outcomes. These findings suggest that obesity as a comorbid factor should be considered at the clinical presentation in children with MIS-C.