Age-Dependent Variations in Kawasaki Disease Incidence in Japan.

Importance: The etiology of Kawasaki disease (KD) remains elusive, with immunologic and epidemiologic data suggesting different triggers in individuals who are genetically susceptible. KD remains the most common cause of acquired heart disease in pediatric patients, and Japan is the country of highest incidence, with an increasing number of cases. Objective: To investigate whether an analysis of the epidemiologic KD record in Japan stratified by age and prefecture (subregion) may yield new clues regarding mechanisms of exposure to etiologic agents associated with KD. Design, Setting, and Participants: This cross-sectional study was conducted using a dataset of patients with KD with detailed information on location and age at onset created through nationwide surveys of hospitals caring for pediatric patients with KD throughout Japan. Pediatric patients hospitalized in Japan for KD from 1970 to 2020 were included. Data were analyzed from January 2022 to January 2024. Exposure: Pediatric patients with KD. Main Outcomes and Measures: The KD dataset was analyzed by patient age (infants [aged <6 months], toddlers [aged 6 to <24 months], children aged 2 years [aged 24 to <36 months], and children and adolescents aged 3 years or older [aged ≥36 months]), with investigations of seasonal cycles, interannual variations, and correlations across regions. Results: Among 422 528 pediatric patients (243 803 males [57.7%] and 178 732 females [42.3%]; median [IQR] age, 23.69 [11.96-42.65] months), infants, toddlers, and patients aged 3 years or older exhibited different rates of increase in KD incidence, seasonality, and degrees of coherence of seasonality across prefectures. Although the mean (SD) incidence of KD among infants remained relatively stable over the past 30 years compared with older patients (1.00 [0.07] in 1987-1992 to 2.05 [0.11] in 2011-2016), the mean (SD) incidence rate for children and adolescents aged 3 years or older increased 5.2-fold, from 1.00 (0.08) in 1987 to 1992 to 5.17 (0.46) in 2014 to 2019. Patients aged 3 years or older saw a reduction in mean (SD) incidence, from peaks of 5.71 (0.01) in October 2014 through June 2015 and July 2018 through March 2019 to 4.69 (0.11) in 2016 to 2017 (17.8% reduction) not seen in younger children. The seasonal cycle varied by age group; for example, mean (SD) incidence peaked in July and August (5.63 [0.07] cases/100 000 individuals) for infants and in December and January (4.67 [0.13] cases/100 000 individuals) for toddlers. Mean (SD) incidence changed dramatically for toddlers beginning in the early 2010s; for example, the normalized mean (SD) incidence among toddlers for October was 0.74 (0.03) in 1992 to 1995 and 1.10 (0.01) in 2016 to 2019. Across Japan, the seasonal cycle of KD incidence of older children and adolescents exhibited mean (SD) correlation coefficients between prefectures as high as 0.78 (0.14) for prefecture 14 among patients aged 3 years or older, while that of infants was much less (highest mean [SD] correlation coefficient, 0.43 [0.23]). Conclusions and Relevance: This study found distinct temporal signatures and changing spatial consistency of KD incidence across age groups, suggesting different age-related mechanisms of exposure. Some results suggested that social factors may modulate exposure to etiologic agents of KD; however, the increase in KD incidence in older children coupled with the correlation across prefectures of KD incidence suggest that the intensity of an environmental exposure that triggers KD in this age group may have increased over time.

DOACs in Patients With Giant Coronary Artery Aneurysms After Kawasaki Disease.

This case series examines outcomes among patients with giant coronary artery aneurysms after Kawasaki disease treated with direct oral anticoagulants (DOACs).

Association of Yersinia Infection With Kawasaki Disease: A Prospective Multicenter Cohort Study.

BACKGROUND: Yersinia infection is known to present with Kawasaki disease (KD)-like symptoms although differentiating the 2 has been a challenge. The present study aimed to describe the clinical characteristics and prevalence of Yersinia infection presenting with KD-like symptoms. METHODS: The present, prospective, multicenter study enrolled patients who received a diagnosis of KD between January 2021 and January 2022 at 2 hospitals in Tokyo. Stool samples were collected within 3 days of the start of KD treatment, and cultures were performed for Yersinia . Clinical history and symptoms suggestive of Yersinia infection were also evaluated. RESULTS: During the study period, 141 KD patients were screened and 117 patients with evaluable stool samples were registered. Only 1 patient was positive for Yersinia pseudotuberculosis , which was detected from both stool and blood cultures. The patient was refractory to KD treatment but improved after initiation of appropriate antibiotic therapy. CONCLUSIONS: Routine screening for Yersinia is not appropriate for patients with KD and should be limited to certain patients in high-risk areas and those who are refractory to the standard KD treatment.

Clinical implications of gallbladder enlargement in Kawasaki disease.

BACKGROUND: Kawasaki disease (KD) presents with gallbladder enlargement (GBE) or hydrops in the acute phase. Although GBE is highly specific to KD, epidemiological data on GBE have not been updated. In this study we evaluated the occurrence rate of GBE in KD and characterized the clinical features of patients who developed GBE. METHODS: The present study was a prospective, observational study. The maximum longitudinal area of the gallbladder and the common bile duct diameter in KD patients were measured by ultrasonography at the start of initial intravenous immunoglobulin (IVIG) therapy (day 0) and on days 7, 30, and 60 of therapy. The primary outcome was the complication rate of GBE (z- score ≥2.0) on day 0. The secondary outcome was the association of GBE with cholestasis, unresponsiveness to IVIG, and coronary artery lesions (CAL). RESULTS: Gallbladder enlargement occurred in 35% (35/101) of patients on day 0. Cholestasis and severe patients (Kobayashi score [KS] ≥5) were more common in the GBE group (20.6% vs. 1.6%, p = 0.002, and 54.3% vs. 15.2%, p < 0.001, respectively). In patients with a KS of ≤4, the non-responder rate was higher in the GBE group (44% vs. 20%, p = 0.0495) but did not differ in those with a KS of ≥5 (21% vs. 20%, p = 0.95). The rate of CAL occurrence did not differ significantly between the groups (8.6% vs. 6.1%, p = 0.64). CONCLUSIONS: Gallbladder enlargement occurred in 35% of KD patients and was associated with cholestasis. Gallbladder enlargement may not only be a diagnostic finding, but also a severity marker in KD patients.

Infliximab for intensification of primary therapy for patients with Kawasaki disease and coronary artery aneurysms at diagnosis.

OBJECTIVE: Children with Kawasaki disease (KD) and an initial echocardiogram that demonstrates coronary artery aneurysms (CAAs, Z score ≥2.5) are at high risk for severe cardiovascular complications. We sought to determine if primary adjunctive infliximab treatment at a dose of either 5 or 10 mg/kg, compared with intravenous immunoglobulin (IVIG) alone, is associated with a greater likelihood of CAA regression in patients with KD with CAA at the time of diagnosis. DESIGN AND SETTING: Single-centre observational study. PATIENTS: Children with acute KD and Z score ≥2.5 at baseline. INTERVENTIONS: Primary adjunctive infliximab (5 or 10 mg/kg) within 48 hours of initiating IVIG 2 g/kg. MAIN OUTCOME MEASURES: Incidence of CAA regression to Zmax <2 within 2 months of disease onset. RESULTS: Of the 168 patients with KD, 111 received IVIG alone and 57 received primary adjunctive infliximab therapy: 39 received 5 mg/kg and 18 received 10 mg/kg. Incidence of CAA regression to Zmax <2 within 2 months was statistically significant at 52%, 62% and 83% in the IVIG alone, IVIG+infliximab 5 mg/kg and IVIG+infliximab 10 mg/kg, respectively. The multivariable logistic regression model adjusting for age, sex, baseline Zmax and bilateral CAA at baseline showed that IVIG plus 10 mg/kg infliximab was significantly associated with a greater likelihood of CAA regression (adjusted OR: 4.45, 95% CI 1.17 to 16.89, p=0.028) compared with IVIG alone. The difference between IVIG+infliximab 5 mg/kg and IVIG alone was not significant. CONCLUSIONS: Primary adjunctive high-dose 10 mg/kg infliximab treatment was associated with a greater likelihood of CAA regression in patients with CAA at the time of diagnosis.

Identifying Kawasaki Disease With a Low Coronary Artery Aneurysm Risk.

INTRODUCTION: Kawasaki disease (KD) patients with a high risk of coronary artery aneurysm (CAA) development are well characterized and targeted for intensified primary intravenous immunoglobulin (IVIG) treatment. However, the characteristics of KD patients with a low CAA risk are less well-known. METHODS: The present study was a secondary analysis of Prospective Observational study on STRAtified treatment with Immunoglobulin plus Steroid Efficacy for Kawasaki disease (Post RAISE), a multicenter, prospective cohort study of KD patients in Japan. The target of the analysis was patients with a Kobayashi score <5 who were predicted to respond to IVIG. The incidence of CAA during the acute phase, the primary outcome, was assessed based on all echocardiographic evaluations performed between week 1 (days 5-9) and month 1 (days 20-50) after the start of primary treatment. Multivariable logistic regression was used to identify the independent risk factors of CAA during the acute phase, based on which a decision tree was created to identify a subpopulation of patients with KD with a low CAA risk. RESULTS: Multivariate analysis found that a baseline maximum Z score >2.5, age <12 months at fever onset, nonresponsiveness to IVIG, low neutrophils, high platelets and high C-reactive protein were independent predictors of CAA during the acute phase. The decision tree created by using these risk factors identified 679 KD patients who had a low incidence of CAA during the acute phase (4.1%) and no medium or large CAA. CONCLUSIONS: The present study identified a KD subpopulation with a low CAA risk comprising around a quarter of the entire Post RAISE cohort.

Risk Factors of Coronary Artery Aneurysms in Kawasaki Disease with a Low Risk of Intravenous Immunoglobulin Resistance: An Analysis of Post RAISE.

OBJECTIVE: To detect risk factors of coronary artery aneurysm (CAA) development in patients with Kawasaki disease determined to have a low risk for resistance to primary intravenous immunoglobulin (IVIG) treatment based on the Kobayashi score. STUDY DESIGN: This study included 1757 predicted IVIG responders from Prospective Observational study on STRAtified treatment with Immunoglobulin plus Steroid Efficacy for Kawasaki disease (Post RAISE), a large-scale, multicenter, prospective cohort study of Kawasaki disease in Japan. Predicted IVIG responders were defined as patients with Kawasaki disease with a Kobayashi score of <5, a predictive scoring system for IVIG resistance created in Japan. The primary outcome was CAA development at 1 month after disease onset. CAA was defined as a Z score of ≥2.5. Multivariable logistic regression was used to identify the independent risk factors of CAA. The variables for inclusion were identified based on univariate analysis results and previously reported risk factors of CAA. RESULTS: Among 1632 patients who had complete coronary outcome data, CAA developed in 90 patients (5.5%) at 1 month after disease onset. Multivariable analysis found that a baseline maximum Z score of >2.5, age of <12 months at fever onset, and nonresponsiveness to IVIG were significant, independent risk factors of CAA development at 1 month after disease onset. Among the risk factors, a baseline maximum Z score of >2.5 was most strongly associated with CAA development (OR, 7.1; 95% CI, 4.1-12.2; P ≤ .001). CONCLUSIONS: Predicted IVIG responders with CAA risk factors identified in this study may be candidates for future clinical trials of intensified primary IVIG treatment with prednisolone, cyclosporine or infliximab.

Follow-Up Duration of Echocardiography in Patients with Kawasaki Disease with No Initial Coronary Aneurysms.

OBJECTIVE: To evaluate the optimal duration of echocardiographic follow-up in patients with Kawasaki disease without an initial coronary aneurysm. STUDY DESIGN: In this single-center, retrospective, observational study, we reviewed the results of follow-up echocardiography in children with Kawasaki disease enrolled in the Prospective Observational Study on Stratified Treatment with Immunoglobulin Plus Steroid Efficacy for Kawasaki Disease from a children's hospital. The main enrollment criterion was the absence of coronary aneurysms, defined as a maximum z-score (Zmax) ≥2.5, in the proximal right coronary artery and the proximal left anterior descending artery within 9 days from treatment initiation. The primary outcome was Zmax on follow-up echocardiography at up to 5 years. RESULTS: Among 386 patients, 106 (27.5%) received prednisolone with intravenous immunoglobulin for first-line therapy, and 57 (14.8%) showed a poor response. Echocardiography at 1 month detected 9 patients with a Zmax ≥2, including 3 (0.8%) with coronary aneurysms requiring additional antithrombotic treatment and observation. Of 7 patients (1.8%) with normal echocardiographic findings at 1 month but a Zmax ≥2 later, 2 were lost to follow-up and 5 experienced spontaneous resolution, but none of the 7 patients required any change in management. CONCLUSIONS: The optimal duration of echocardiographic follow-up may be 1 month in patients with no initial coronary aneurysms and a Zmax <2 at 1 month. Coronary artery abnormalities observed after 1 month are rare and mostly benign in this category of patients.

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.

Evaluation of a Kawasaki Disease Risk Model for Predicting Coronary Artery Aneurysms in a Japanese Population: An Analysis of Post RAISE.

OBJECTIVES: To test the performance of the Son risk score, which was created to predict coronary artery abnormalities from baseline variables in North American patients with Kawasaki disease. STUDY DESIGN: The dataset from Post RAISE, the largest prospective cohort study of Japanese patients with Kawasaki disease to date, was used for the present study. With high risk defined as ≥3 points, sensitivity, specificity, positive predictive value, and negative predictive value for coronary artery abnormality development were calculated. To evaluate the effect of each risk factor in the Son score, the OR and 95% CIs were calculated using logistic regression analysis with the presence of coronary artery abnormality at 1 month after disease onset. RESULTS: Post RAISE enrolled 2628 consecutive patients with Kawasaki disease, and 304 patients had a high-risk score, of whom 15.1% showed coronary artery abnormality. At the cutoff ≥3 points, the sensitivity was 37.7%, and the specificity was 87.2%. The maximum z score at baseline ≥2.0 (OR 3.5, 95% CI 2.3-5.2) and age <6 months at disease onset (OR 3.2, 95% CI 1.9-5.4), were significantly associated with coronary artery abnormality development. However, a high concentration of C-reactive protein was not associated with coronary artery abnormality. The area under the receiver operating characteristic curve for the Son score was 0.65 (95% CI 0.59-0.71). CONCLUSIONS: The Son score had insufficient sensitivity and good specificity in a Japanese cohort of patients with Kawasaki disease. Among the variables comprising the Son score, a large baseline z score and young age at disease onset were significant, independent predictors of coronary artery abnormality development.

Risk Factors of Coronary Artery Abnormalities and Resistance to Intravenous Immunoglobulin Plus Corticosteroid Therapy in Severe Kawasaki Disease: An Analysis of Post RAISE.

BACKGROUND: Coronary artery abnormalities (CAAs) still occur in patients with Kawasaki disease receiving intensified treatment with corticosteroids. We aimed to determine the risk factors of CAA development and resistance to intensified treatment in Post RAISE (Prospective Observational Study on Stratified Treatment With Immunoglobulin Plus Steroid Efficacy for Kawasaki Disease)-the largest prospective cohort of Kawasaki disease patients to date. METHODS: In Post RAISE, 2648 consecutive patients with Kawasaki disease were enrolled. The present study analyzed 724 patients predicted to be intravenous immunoglobulin (IVIG) nonresponders (Kobayashi score ≥5) who received intensified treatment consisting of IVIG plus prednisolone. The association between the baseline characteristics and CAA at 1 month after disease onset was examined. The association between the baseline characteristics and treatment resistance was also investigated. RESULTS: Maximum Z score at baseline ≥2.5 (odds ratio, 3.4 [95% CI, 1.5-7.8]), age at fever onset <1 year (odds ratio, 3.4 [95% CI, 1.6-7.4]), and nonresponsiveness to IVIG plus prednisolone treatment (odds ratio, 6.8 [95% CI, 3.3-14.0]) were independent predictors of CAA development. Nonresponsiveness to IVIG plus prednisolone was significantly associated with 8 baseline variables. Baseline total bilirubin (odds ratio, 1.4 [95% CI, 1.2-1.7]) was the only significant independent predictor other than the variables included in the Kobayashi score, enabling treatment resistance to be identified at diagnosis. The area under the ROC curve was 0.74 (95% CI, 0.69-0.79). At a cutoff point of 1.0, the sensitivity and specificity for predicting treatment resistance were 71% and 65%, respectively. CONCLUSIONS: In Post RAISE, younger age at fever onset, a larger maximum Z score at baseline, and nonresponsiveness to IVIG plus prednisolone were risk factors significantly associated with CAA development. Nonresponders were able to be identified at diagnosis based on the total bilirubin value. To prevent CAA, more intensified or adjunctive therapies using other agents, such as pulsed methylprednisolone, ciclosporin, infliximab, and Anakinra, should be considered for patients with these risk factors. Registration: URL: https://www.umin.ac.jp/ctr/; Unique identifier: UMIN000007133.

Decreased hemoglobin after initial treatment is associated with treatment resistance in Kawasaki disease in Kobayashi risk stratification.

BACKGROUND: Although Kawasaki disease (KD) is known to cause anemia, the relationship between its prognosis and hemoglobin level is less well known. METHODS: We herein performed a secondary analysis of data from a previous study (Post-RAISE). Children aged 6 months to 2 years at the time of KD diagnosis were enrolled. Decreased hemoglobin was defined as a decrease > 10% on post-treatment day 2 compared with the level prior to the initial therapy. RESULTS: Of 1253 KD cases, treatment resistance was observed in 209 (17%) and was significantly more frequent in the decreased hemoglobin group (37/167 vs. 172/1086, P = 0.041). Multivariable logistic regression analysis revealed that decreased hemoglobin was associated with resistance to the initial treatment (odds ratio 1.53; 95% confidence interval 1.00-2.33; P = 0.048). CONCLUSIONS: Decreased hemoglobin was significantly associated with resistance to initial treatment in patients with KD.

Efficacy and safety of intravenous immunoglobulin plus prednisolone therapy in patients with Kawasaki disease (Post RAISE): a multicentre, prospective cohort study.

BACKGROUND: The RAISE study showed that additional prednisolone improved coronary artery outcomes in patients with Kawasaki disease at high risk of intravenous immunoglobulin (IVIG) resistance. However, no studies have been done to test the steroid regimen used in the RAISE study. We therefore aimed to verify the efficacy and safety of primary IVIG plus prednisolone. METHODS: We did a multicentre, prospective cohort study at 34 hospitals in Japan. We included patients diagnosed with Kawasaki disease according to the Japanese diagnostic criteria, and excluded those who were treated at other hospitals before being transferred to a participating hospital. Patients who were febrile at diagnosis received primary IVIG (2 g/kg per 24 h) and oral aspirin (30 mg/kg per day) until the fever resolved, followed by oral aspirin (5 mg/kg per day) for 2 months after Kawasaki disease onset. We stratified patients using the Kobayashi score into predicted IVIG non-responders (Kobayashi score ≥5) or predicted IVIG responders (Kobayashi score <5). For predicted non-responders, each hospital independently decided whether to add prednisolone (intravenous injection of 2 mg/kg per day for 5 days) to the primary IVIG treatment, according to their respective treatment policy, and we further divided these patients based on the primary treatment received. The primary endpoint was the incidence of coronary artery abnormalities determined by two-dimensional echocardiography at 1 month after the primary treatment in predicted non-responders treated with primary IVIG plus prednisolone. Coronary artery abnormalities were defined according to the criteria of the Japanese Ministry of Health and Welfare and of the American Heart Association (AHA). This study is registered with the University Hospital Medical Information Network Clinical Trials Registry, number UMIN000007133. FINDINGS: From July 1, 2012, to June 30, 2015, we enrolled 2628 patients with Kawasaki disease, of whom 724 (27·6%) were predicted IVIG non-responders who received IVIG plus prednisolone as primary treatment. 132 (18·2%) of 724 patients did not respond to primary treatment. Among patients with complete data, coronary artery abnormalities were present in 40 (incidence rate 5·9%, 95% CI 4·3-8·0) of 676 patients according to the AHA criteria or in 26 (3·8%, 2·5-5·6) of 677 patients according to the Japanese criteria. Serious adverse events were reported in 12 (1·7%) of 724 patients treated with primary IVIG plus prednisolone; two of these patients had hypertension and bacteraemia that was probably related to prednisolone. One patient died possibly due to severe inflammation from the Kawasaki disease itself. INTERPRETATION: Primary IVIG plus prednisolone therapy in this study had an effect similar to that seen in the RAISE study in reducing the non-response rate and decreasing the incidence of coronary artery abnormalities. A primary IVIG and prednisolone combination therapy might prevent coronary artery abnormalities and contribute to lowering medical costs. FUNDING: Tokyo Metropolitan Government Hospitals and the Japan Kawasaki Disease Research Center.

7-Hydroxy- N-Methylquinolinium Chromophore: A Photolabile Protecting Group for Blue-Light Uncaging.

The development of the N-methyl-7-hydroxymethylquinolinium ( N-Me-7-HQm) caging chromophore as a novel visible-light-sensitive photolabile protecting group is described. N-Me-7-HQm-caged compounds can be photoactivated by blue-light-emitting diode (LED) light (458 nm) with high photolytic efficiency, supporting applications to caging chemistry, and they also have sufficient water solubility and high resistance to spontaneous hydrolysis.

[Primary Pulmonary Vein Stenosis Developed after Bidirectional Glenn Procedure;Report of Two Cases].

We experienced 2 cases of primary pulmonary vein stenosis(PVS),which developed after a bidirectional Glenn procedure was performed for complex heart defects with normal pulmonary venous return. Although the patients successfully underwent primary sutureless repair for left PVS, restenosis of the affected pulmonary veins occurred several months after surgery in both patients. Stent implantation followed by balloon angioplasty was performed for stent stenosis in 1 patient without effect. However, the patient later underwent a successful fenestrated Fontan procedure. Catheter intervention was contraindicated in the 2nd patient due to almost complete obstruction of the left pulmonary veins with upstream hypoplasia. To improve the results of PVS treatment, earlier diagnosis by quantitative lung perfusion scintigraphy, magnetic resonance imaging, and close echocardiographic observation together with earlier, aggressive treatment combining surgery and catheter interventions are recommended.

Retrospective observational study indicates that the paediatric assessment triangle may suggest the severity of Kawasaki disease.

AIM: We examined whether the paediatric assessment triangle (PAT) could predict the severity of Kawasaki disease. METHODS: We enroled patients diagnosed with Kawasaki disease between July 2012 and June 2016 at the emergency department of Tokyo Metropolitan Children's Medical Center in Tokyo, Japan. Triage nurses assigned participants to unstable or stable PAT groups. We compared the incidence of coronary artery aneurysms (CAA), the Kobayashi score, which measures resistance to intravenous immunoglobulin treatment, and the incidence of initial treatment resistance. RESULTS: Of the 420 participants, who were aged 0-145 months with a mean age of 31.2 ± 23.9 months, 66 (16%) were assigned to the unstable PAT group. The incidence of CAA was similar between the two groups. The percentage of unstable PAT group participants with a Kobayashi score of at least five points (39 versus 18%, p < 0.001) and initial treatment resistance (25 versus 15%, p = 0.047) were significantly higher than in the stable PAT group. Unstable PAT was an independent risk factor for initial treatment resistance (odds ratio 2.02, 95% confidence interval 1.05-3.90, p = 0.035). CONCLUSION: An unstable PAT was able to predict the severity of Kawasaki disease when measured by a higher rate of initial treatment resistance.