Partial cardiopulmonary bypass through left thoracotomy for coarctation repair in children.

BACKGROUND: A left thoracotomy approach is anatomically appropriate for childhood aortic coarctation; however, the pediatric femoral arteriovenous diameters are too small for cardiopulmonary bypass cannulation. We aimed to determine the safety of a partial cardiopulmonary bypass through the main pulmonary artery and the descending aorta in pediatric aortic coarctation repair. METHODS: We retrospectively reviewed 10 patients who underwent coarctation repair under partial main pulmonary artery-to-descending aorta cardiopulmonary bypass with a left thoracotomy as the CPB group. During the same period, 16 cases of simple coarctation of the aorta repair, with end-to-end anastomosis through a left thoracotomy without partial CPB assistance, were included as the non-CPB group to evaluate the impact of partial CPB. RESULTS: The median age and weight at surgery of the CPB group were 3.1 years (range, 9 days to 17.9 years) and 14.0 (range, 2.8-40.7) kg, respectively. Indications for the partial cardiopulmonary bypass with overlap were as follows: age > 1 year (n = 7), mild aortic coarctation (n = 3), and predicted ischemic time > 30 min (n = 5). Coarctation repair using autologous tissue was performed in seven cases and graft replacement in three. The mean partial cardiopulmonary bypass time, descending aortic clamp time, and cardiopulmonary bypass flow rate were 73 ± 37 min, 57 ± 27 min, and 1.6 ± 0.2 L/min/m2, respectively. Urine output during descending aortic clamping was observed in most cases in the CPB group (mean: 9.1 ± 7.9 mL/kg/h), and the total intraoperative urine output was 3.2 ± 2.7 mL/kg/h and 1.2 ± 1.5 mL/kg/h in the CPB and non-CPB group, respectively (p = 0.020). The median ventilation time was 1 day (range, 0-15), and the intensive care unit stay duration was 4 days (range, 1-16) with no surgical deaths. No major complications, including paraplegia or recurrent coarctation, occurred postoperatively during a median observation period of 8.1 (range, 3.4-17.5) years in the CPB group. In contrast, reoperation with recurrent coarctation was observed in 2 cases in the non-CPB group (p = 0.37). CONCLUSIONS: Partial cardiopulmonary bypass through the main pulmonary artery and descending aorta via a left thoracotomy is a safe and useful option for aortic coarctation repair in children.

Comparison between transcatheter versus surgical intervention for pediatric aortic valvular stenosis: a multicenter study in Japan.

It is controversial whether children with isolated aortic valvular stenosis (vAS) initially undergo transcatheter or surgical aortic valvuloplasty (BAV or SAV). This multicenter retrospective case-control study aimed to explore outcomes after BAV or SAV for pediatric vAS. We studied children (aged < 15 years) with vAS treated at 4 tertiary congenital heart centers, and compared the rates of survival, reintervention, and valve replacement between patients with BAV and SAV. A total of 73 subjects (BAV: N = 52, SAV: N = 21) were studied. Age and aortic annulus z-score at the first presentation were 85 (26-530) days and - 0.45 (- 1.51-0.59), respectively. During the follow-up period of 121 (47-185) months, rates of 10-year survival (BAV: 88% vs. SAV: 92%, P = 0.477), reintervention (BAV: 58% vs. SAV: 31%, P = 0.626), and prosthetic/autograft valve replacement (BAV: 21% vs. SAV: 19%, P = 0.563) did not differ between the groups. Freedom from reintervention rate significantly correlated with aortic annulus z-score (hazard ratio [HR] 0.66, 95% confidence interval [CI] 0.49-0.88, P = 0.005), and freedom from prosthetic/autograft valve replacement rate significantly correlated to the degree of aortic regurgitation after the first intervention (HR: 4.58, 95% CI 1.19-17.71, P = 0.027). Propensity score-matched analysis (N = 16) did not show the differences in survival and reintervention rates between the groups. Long-term survival was acceptable, and the rates of freedom from reintervention and prosthetic/autograft valve replacement were comparable between children with vAS who underwent BAV and SAV.

Identification of Prostaglandin I2 Synthase Rare Variants in Patients With Williams Syndrome and Severe Peripheral Pulmonary Stenosis.

BACKGROUND: Peripheral pulmonary stenosis (PPS) is a condition characterized by the narrowing of the pulmonary arteries, which impairs blood flow to the lung. The mechanisms underlying PPS pathogenesis remain unclear. Thus, the aim of this study was to investigate the genetic background of patients with severe PPS to elucidate the pathogenesis of this condition. METHODS AND RESULTS: We performed genetic testing and functional analyses on a pediatric patient with PPS and Williams syndrome (WS), followed by genetic testing on 12 patients with WS and mild-to-severe PPS, 50 patients with WS but not PPS, and 21 patients with severe PPS but not WS. Whole-exome sequencing identified a rare PTGIS nonsense variant (p.E314X) in a patient with WS and severe PPS. Prostaglandin I2 synthase (PTGIS) expression was significantly downregulated and cell proliferation and migration rates were significantly increased in cells transfected with the PTGIS p.E314X variant-encoding construct when compared with that in cells transfected with the wild-type PTGIS-encoding construct. p.E314X reduced the tube formation ability in human pulmonary artery endothelial cells and caspase 3/7 activity in both human pulmonary artery endothelial cells and human pulmonary artery smooth muscle cells. Compared with healthy controls, patients with PPS exhibited downregulated pulmonary artery endothelial prostaglandin I2 synthase levels and urinary prostaglandin I metabolite levels. We identified another PTGIS rare splice-site variant (c.1358+2T>C) in another pediatric patient with WS and severe PPS. CONCLUSIONS: In total, 2 rare nonsense/splice-site PTGIS variants were identified in 2 pediatric patients with WS and severe PPS. PTGIS variants may be involved in PPS pathogenesis, and PTGIS represents an effective therapeutic target.

The c.1617del variant of TMEM260 is identified as the most frequent single gene determinant for Japanese patients with a specific type of congenital heart disease.

Although the molecular mechanisms underlying congenital heart disease (CHD) remain poorly understood, recent advances in genetic analysis have facilitated the exploration of causative genes for CHD. We reported that the pathogenic variant c.1617del of TMEM260, which encodes a transmembrane protein, is highly associated with CHD, specifically persistent truncus arteriosus (PTA), the most severe cardiac outflow tract (OFT) defect. Using whole-exome sequencing, the c.1617del variant was identified in two siblings with PTA in a Japanese family and in three of the 26 DNAs obtained from Japanese individuals with PTA. The c.1617del of TMEM260 has been found only in East Asians, especially Japanese and Korean populations, and the frequency of this variant in PTA is estimated to be next to that of the 22q11.2 deletion, the most well-known genetic cause of PTA. Phenotype of patients with c.1617del appears to be predominantly in the heart, although TMEM260 is responsible for structural heart defects and renal anomalies syndrome (SHDRA). The mouse TMEM260 variant (p.W535Cfs*56), synonymous with the human variant (p.W539Cfs*9), exhibited truncation and downregulation by western blotting, and aggregation by immunocytochemistry. In situ hybridization demonstrated that Tmem260 is expressed ubiquitously during embryogenesis, including in the development of cardiac OFT implicated in PTA. This expression may be regulated by a ~ 0.8 kb genomic region in intron 3 of Tmem260 that includes multiple highly conserved binding sites for essential cardiac transcription factors, thus revealing that the c.1617del variant of TMEM260 is the major single-gene variant responsible for PTA in the Japanese population.

Corrigendum: Use of the index of pulmonary vascular disease for predicting longterm outcome of pulmonary arterial hypertension associated with congenital heart disease.

[This corrects the article DOI: 10.3389/fcvm.2023.1212882.].

Home-inhaled nitric oxide in a child with pulmonary arterial hypertension associated with post-operative pulmonary venous obstruction.

Home-inhaled nitric oxide therapy was effective and feasible in the patients with intractable pulmonary arterial hypertension. We present the case of a child with severe pulmonary arterial hypertension associated with post-operative pulmonary venous obstruction who was treated with home-inhaled nitric oxide therapy.

Use of the index of pulmonary vascular disease for predicting long-term outcome of pulmonary arterial hypertension associated with congenital heart disease.

Aims: Limited data exist on risk factors for the long-term outcome of pulmonary arterial hypertension (PAH) associated with congenital heart disease (CHD-PAH). We focused on the index of pulmonary vascular disease (IPVD), an assessment system for pulmonary artery pathology specimens. The IPVD classifies pulmonary vascular lesions into four categories based on severity: (1) no intimal thickening, (2) cellular thickening of the intima, (3) fibrous thickening of the intima, and (4) destruction of the tunica media, with the overall grade expressed as an additive mean of these scores. This study aimed to investigate the relationship between IPVD and the long-term outcome of CHD-PAH. Methods: This retrospective study examined lung pathology images of 764 patients with CHD-PAH aged <20 years whose lung specimens were submitted to the Japanese Research Institute of Pulmonary Vasculature for pulmonary pathological review between 2001 and 2020. Clinical information was collected retrospectively by each attending physician. The primary endpoint was cardiovascular death. Results: The 5-year, 10-year, 15-year, and 20-year cardiovascular death-free survival rates for all patients were 92.0%, 90.4%, 87.3%, and 86.1%, respectively. The group with an IPVD of ≥2.0 had significantly poorer survival than the group with an IPVD <2.0 (P = .037). The Cox proportional hazards model adjusted for the presence of congenital anomaly syndromes associated with pulmonary hypertension, and age at lung biopsy showed similar results (hazard ratio 4.46; 95% confidence interval: 1.45-13.73; P = .009). Conclusions: The IPVD scoring system is useful for predicting the long-term outcome of CHD-PAH. For patients with an IPVD of ≥2.0, treatment strategies, including choosing palliative procedures such as pulmonary artery banding to restrict pulmonary blood flow and postponement of intracardiac repair, should be more carefully considered.

Calmodulinopathy in Japanese Children　- Their Cardiac Phenotypes Are Severe and Show Early Onset in Fetal Life and Infancy.

BACKGROUND: Cardiac calmodulinopathy, characterized by a life-threatening arrhythmia and sudden death in the young, is extremely rare and caused by genes encoding calmodulin, namely calmodulin 1 (CALM1), CALM2, and CALM3.Methods and Results: We screened 195 symptomatic children (age 0-12 years) who were suspected of inherited arrhythmias for 48 candidate genes, using a next-generation sequencer. Ten probands were identified as carrying variants in any of CALM1-3 (5%; median age 5 years), who were initially diagnosed with long QT syndrome (LQTS; n=5), catecholaminergic polymorphic ventricular tachycardia (CPVT; n=3), and overlap syndrome (n=2). Two probands harbored a CALM1 variant and 8 probands harbored 6 CALM2 variants. There were 4 clinical phenotypes: (1) documented lethal arrhythmic events (LAEs): 4 carriers of N98S in CALM1 or CALM2; (2) suspected LAEs: CALM2 p.D96G and D132G carriers experienced syncope and transient cardiopulmonary arrest under emotional stimulation; (3) critical cardiac complication: CALM2 p.D96V and p.E141K carriers showed severe cardiac dysfunction with QTc prolongation; and (4) neurological and developmental disorders: 2 carriers of CALM2 p.E46K showed cardiac phenotypes of CPVT. Beta-blocker therapy was effective in all cases except cardiac dysfunction, especially in combination with flecainide (CPVT-like phenotype) and mexiletine (LQTS-like). CONCLUSIONS: Calmodulinopathy patients presented severe cardiac features, and their onset of LAEs was earlier in life, requiring diagnosis and treatment at the earliest age possible.

Transcatheter atrial septal defect closure late after completion of biventricular circulation in patients with pulmonary atresia intact ventricular septum or critical pulmonary stenosis.

OBJECTIVE: This study aimed to explore anatomical and hemodynamic features of atrial septal defect, which was treated by transcatheter device closure late after completion of biventricular circulation in patients with pulmonary atresia and intact ventricular septum (PAIVS) or critical pulmonary stenosis (CPS). METHODS: We studied echocardiographic and cardiac catheterization data, including defect size, retroaortic rim length, single or multiple defects, the presence of malalignment atrial septum, tricuspid and pulmonary valve diameters, and cardiac chamber sizes, in patients with PAIVS/CPS who underwent transcatheter closure of atrial septal defect (TCASD), and compared to control subjects. RESULTS: A total of 173 patients with atrial septal defect, including 8 patients with PAIVS/CPS, underwent TCASD. Age and weight at TCASD were 17.3 ± 18.3 years and 36.6 ± 13.9 kg, respectively. There was no significant difference in defect size (13.7 ± 4.0 vs. 15.6 ± 5.2 mm, p = 0.317) and the retro-aortic rim length (3.7 ± 4.3 vs. 3.6 ± 0.3.1 mm, p = 0.948) between the groups; however, multiple defects (50% vs. 5%, p < 0.001) and malalignment atrial septum (62% vs. 14%. p < 0.001) were significantly frequent in patients with PAIVS/CPS compared to control subjects. The ratio of pulmonary to systemic blood flow in patients with PAIVS/CPS was significantly lower than that in the control patients (1.2 ± 0.4 vs. 2.0 ± 0.7, p < 0.001); however, four out of eight patients with atrial septal defect associated with PAIVS/CPS had right-to-left shunt through a defect, who were evaluated by the balloon occlusion test before TCASD. The indexed right atrial and ventricular areas, the right ventricular systolic pressure, and mean pulmonary arterial pressure did not differ between the groups. After TCASD, the right ventricular end-diastolic area remained unchanged in patients with PAIVS/CPS, whereas it significantly decreased in control subjects. CONCLUSIONS: Atrial septal defect associated with PAIVS/CPS had more complex anatomy, which would be a risk for device closure. Hemodynamics should be individually evaluated to determine the indication for TCASD because PAIVS/CPS encompassed anatomical heterogeneity of the entire right heart.

Transcatheter retrieval of atrial septal defect and patent ductus arteriosus occluder: a guidance for device retrieval based on comprehensive bench tests.

OBJECTIVES: The aim of this study is to establish a guidance for device retrieval based on comprehensive bench tests. BACKGROUND: Device embolisation remains a major complication in transcatheter closure of atrial septal defect and patent ductus arteriosus. Although percutaneous retrieval is feasible in the majority of cases, surgical retrieval may be required in complicated circumstances. However, the methods of transcatheter device retrieval have not been completely established. METHODS: Bench tests of device retrieval were performed to verify the appropriate retrieval method according to device type/size. The devices used for testing were Amplatzer Septal Occluder (Abbott, Chicago, IL, United States of America), Figulla Flex II (Occlutech GmbH, Jena, Germany), Amplatzer Duct Occluder-I (Abbott), Amplatzer Duct Occluder-II (Abbott), and Amplatzer Vascular Plug-II (Abbott). The retrieval equipment constituted diagnostic catheters (multipurpose catheter and right Judkins catheter, 4-Fr or 5-Fr, Gadelius Medical, Tokyo, Japan), delivery sheath and cables for each device, Amplatz goose neck snares (Medtronic, Minneapolis, MN, United States of America), OSYPKA CATCHER (Osypka ag, Rheinfelden-Herten, Germany), and OSYPKA LASSOS (Osypka). We investigated the retrieval equipment and sheath sizes required for a successful retrieval procedure for variously sized devices. RESULTS: For patent ductus arteriosus devices, the type of snare and the snaring position are considered important. For atrial septal defect devices, simple snare capture or a double-snare technique with a sufficiently large sheath is effective. Special care should be taken when using the OSYPKA CATCHER for device retrieval. CONCLUSIONS: The results of this study may assist in the selection of both capture devices and a retrieval sheath or a catheter for complete retrieval.

Coronary anomalies associated with ventricular septal defect.

Coronary anomalies encompass different conditions in terms of anomalous origin, coursing, and branching, which are occasionally associated with congenital heart disease. This study aimed to explore coronary anomalies associated with ventricular septal defect that was a stereotypical congenital heart disease. We retrospectively reviewed angiographic findings in patients with ventricular septal defect who required corrective surgery, and identified coronary abnormalities, including anomalous origin, coursing, and branching of coronary arteries based on angiography. We studied the prevalence and types of coronary anomalies among them. A total of 998 patients with ventricular septal defect was studied. Age and weight were 2.0 (2.1-15.2) months and 5.7 (4.1-8.7) kg, respectively. There were 115 patients (12%) with syndrome or genetic disorder, and 34 patients (3%) with extracardiac major organ anomalies. The overall prevalence of coronary anomalies was 6.2%. All coronary anomalies were anomalous origin and coursing, among 3 patients accompanied anomalous intrinsic coronary anatomy. Originating within aortic root above the Valsalva sinus was the most common coronary anomaly. Coronary anomalies were independently correlated with bicuspid aortic valve (odds ratio [OR]: 8.02, 95% confidence interval [CI]: 2.34-23.4) and persistent left superior caval vein (OR: 5.02, 95% CI: 1.93-11.7). We showed the possibility that minor cardiac variants, such as bicuspid aortic valve and persistent left superior caval vein, contribute to higher prevalence of coronary anomalies in patients with ventricular septal defect.

Feasibility and Safety of Sodium Glucose Cotransporter-2 Inhibitors in Adults with Heart Failure after the Fontan Procedure.

Sodium glucose cotransporter-2 (SGLT-2) inhibitors have been widespread in patients with heart failure; however, there is little information regarding its feasibility and safety among patients after the Fontan procedure. We presented five adults after the Fontan procedure who were treated with SGLT-2 inhibitors. All patients reduced oedema and/or pleural effusion despite other conjunct medications were ineffective. Although we did not measure the urine volume in all patients, all patients themselves reported an increase in urinary output after the administration of a SGLT-2 inhibitor. In addition, administration of a SGLT-2 inhibitor resulted in weight loss (4/5), an increase in systemic oxygen saturation (4/5), an increase in serum albumin level (4/5), an increase in estimated glomerular filtration ratio (4/5), and a decrease in plasma brain natriuretic peptide level (4/5). Our case series supported the feasibility and safety of SGLT-2 inhibitors in patients with Fontan circulatory failure, although the exact changes in urinary output were unknown in all patients. Further investigation will be required to explore a diuretic effect by SGLT-2 in patients after the Fontan procedure.

Surgical repair of the adult form of scimitar syndrome.

Scimitar syndrome has various clinical presentations and anatomic features, and some cases are diagnosed in adulthood. Reconstruction using autologous tissue to reroute the right pulmonary venous blood flow to the left atrium is ideal. However, if the scimitar vein drains to the caudal segment of the inferior vena cava, reconstruction using prosthetic material may be necessary due to the distance between the left atrium and the scimitar vein. We describe the case of a 16-year-old boy with scimitar syndrome. We anastomosed the scimitar vein to the right atrium using an artificial graft and created an atrial septal defect for rerouting the right pulmonary venous blood to the left atrium. It has been 9 years since this procedure, and the patient has not experienced graft stenosis or thromboembolic events.

Comprehensive assessments of pulmonary circulation in children with pulmonary hypertension associated with congenital heart disease.

Pulmonary hypertension associated with congenital heart disease (CHD-PH) encompasses different conditions confounded by the left-to-right shunt, left heart obstruction, ventricular dysfunction, hypoxia due to airway obstruction, dysplasia/hypoplasia of the pulmonary vasculature, pulmonary vascular obstructive disease, and genetic variations of vasoactive mediators. Pulmonary input impedance consists of the pulmonary vascular resistance (Rp) and capacitance (Cp). Rp is calculated as the transpulmonary pressure divided by the pulmonary cardiac output, whereas Cp is calculated as the pulmonary stroke volume divided by the pulmonary arterial pulse pressure. The plots of Rp and Cp demonstrate a unique hyperbolic relationship, namely, the resistor-capacitor coupling curve, which represents the pulmonary vascular condition. The product of Rp and Cp is the exponential pressure decay, which refers to the time constant. Alterations in Cp are more considerable in CHD patients at an early stage of developing pulmonary hypertension or with excessive pulmonary blood flow due to a left-to-right shunt. The importance of Cp has gained attention because recent reports have shown that low Cp potentially reflects poor prognosis in patients with CHD-PH and idiopathic pulmonary hypertension. It is also known that Cp levels decrease in specific populations, such as preterm infants and trisomy 21. Therefore, both Rp and Cp should be individually evaluated in the management of children with CHD-PH who have different disease conditions.

Being Overweight Is Related to Neoaortic Sinus Dilatation After Arterial Switch Operation.

BACKGROUND: Neoaortic sinus dilatation is a late comorbidity after an arterial switch operation in patients with dextro-transposition of the great arteries. We aim to explore whether neoaortic sinus dilatation is related to overweight or obesity, as these affect aortic remodeling in such patients. METHODS: We measured neoaortic diameters including those for the annulus, sinus, sinotubular junction, and ascending aorta by echocardiography and studied the relationship between these diameters and body mass index in patients aged 15 years and older after an arterial switch operation. RESULTS: A total of 45 patients were studied. Median (interquartile range) age, body mass index, and systolic blood pressure at echocardiography were 20 (17-28) years, 21.2 (18.4-24.2) kg/m2, and 120 (112-127) mm Hg, respectively. Echocardiogram revealed the following median values (interquartile ranges): neoaortic annulus diameter, 22.2 (19.8-23.8) mm; sinus diameter, 34.6 (31.8-39.8) mm; sinotubular junction diameter, 27.5 (22.4-30.0) mm; and ascending aortic diameter, 20.4 (19.4-22.7) mm. The neoaortic sinus diameter was significantly correlated with body mass index (r = 0.41, P = .004) and was significantly larger in patients with concomitant ventricular septal defect (P < .001) and those who were over-weight (body mass index ≥25 kg/m2; P = .006). CONCLUSION: Neoaortic sinus dilatation after an arterial switch operation is associated with being overweight during adolescence and young adulthood. It is important to prevent obesity in patients after an arterial switch operation and educate them on a healthy lifestyle.

Fetal cardiac capillary hemangioma resulting in tachyarrhythmia.

We present the case of a fetus with cardiac capillary hemangioma in the right atrial cavity. The tumor showed dramatic growth between the 28th and 32nd week of gestation and resulted in tachyarrhythmia. The patient was born at the 33 weeks of gestation weighing 2430 g via urgent cesarean section because the rapidly growing cardiac tumor caused incessant tachyarrhythmia, pericardial effusion, and fetal circulatory incompetence. Coronary angiography revealed that the right coronary artery drained into the tumor. Due to hemodynamic deterioration, the patient underwent subtotal resection of the tumor on the 2nd day after birth. Histopathological examination revealed an undifferentiated capillary hemangioma. The patient was discharged at the age of 86 days, as the tachyarrhythmia and hemodynamic incompetence had subsided; however, bradycardia and intermittent atrioventricular conduction disturbance gradually developed. Capillary hemangioma, a rare primary cardiac space-occupying tumor in children, can invade the conduction system.

Overgrowth of the Amygdala in Children with Single Ventricle Congenital Heart Disease.

Aim: Early life stress is associated with overgrowth of the amygdala, which plays a key role in the processing and memory of emotional responses. Herein, we aimed to explore the amygdala volume in children with single-ventricle congenital heart disease who experience repeated admissions during the neonatal period and infancy. Methods: We compared the amygdala volume measured using brain magnetic resonance imaging (MRI) between 40 patients after completion of the Fontan procedure and 40 age- and sex-matched control subjects Results: Age at the MRI study were 9.2 (8.5-11.1) and 10.2 (9.2-10.3) years in the Fontan and control groups, respectively. The maximum amygdala volume in the Fontan group was significantly larger than in the control group (1232 [983-1392] mm3/m2 vs. 980 [728-1166] mm3/m2, P < 0.001). The amygdala volume did not correlate to cardiac index (r = 0.260) and central venous pressure (r = -0.107) in the Fontan group. Conclusions: Children with single-ventricle congenital heart disease exhibited amygdala overgrowth.

The possible association between epidemics of hand-foot-and-mouth disease and responsiveness to immunoglobulin therapy in Kawasaki disease.

Background: Enterovirus causing hand-foot-mouth disease (HFMD) has been reported to be associated with the development of Kawasaki disease (KD), whereas the involvement of enterovirus in the clinical course of KD is uncertain. The aim of this study is to investigate the association between the clinical course of KD and HFMD epidemics. Methods: This study included 108 patients who developed KD during HFMD epidemic seasons (July and August) from 2010 to 2014 and who were initially treated with high-dose intravenous immunoglobulin (IVIG). A mean of ≥5.0 HFMD patients reported weekly from each sentinel medical facility was considered to represent a large HFMD epidemic. We compared the clinical characteristics of KD patients in summers of years with and without large HFMD epidemics. Results: Large HFMD epidemics occurred in 2011 and 2013. The number of KD patients in summer was the highest in 2011. The proportion of patients with resistance to the IVIG therapy in summers of years with the large epidemics (14%) was significantly lower than that in summers of other years (31%, P = 0.030), whereas the proportion of patients with coronary artery abnormalities did not differ to a statistically significant extent. The development of KD during large HFMD epidemics was significantly associated with a lower risk of resistance to the IVIG therapy (incidence rate ratio 0.92, P = 0.049). Conclusion: Patients developing KD during large HFMD epidemic may have good responsiveness to IVIG. It is important to identify microbes from KD patients to predict responsiveness to IVIG therapy.