Ryo Inuzuka

Ryo Inuzuka
The University of Tokyo | Todai · Department of Pediatrics

Doctor of Philosophy

About

125
Publications
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Publications

Publications (125)
Article
Vascular clips are currently acknowledged as a safe and efficient tool for vessel ligation in every surgical field. Here, we describe a case of massive hemoptysis due to perforation of both the aorta and bronchus, caused by a titanium clip that was placed between them 3 years ago. The present case highlights the rare but life-threatening complicati...
Article
Background: Balloon atrial septostomy (BAS) is an essential catheterization procedure for congenital heart lesions. Recently, a balloon catheter for static BAS was approved for the first time in Japan as an alternative to the conventional pull-through BAS. Despite the expected increase in the use of static BAS, reports on its safety are scarce worl...
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Background The Japanese Network of Cardiovascular Departments for Adult Congenital Heart Disease (JNCVD-ACHD) was founded in 2011 for the lifelong care of adult patients with congenital heart disease (ACHD patients). This network maintains the first Japanese ACHD registry. Methods and results From 2011 to 2019, the JNCVD-ACHD registered 54 institu...
Article
We encountered a paediatric case of graft failure due to antibody-mediated rejection after heart transplantation in which ivabradine was effective. Inappropriate sinus tachycardia in denervated transplanted hearts is a good indication for ivabradine administration as beta-blockers have a limited efficacy. To our knowledge, this is the first report...
Article
Objective: Fontan-associated liver disease (FALD) is widely recognised as a common complication in patients long after the Fontan operation. However, data on the predictors of FALD that can guide its screening and management are lacking. The present study aimed to identify the predictors of liver cirrhosis (LC) and hepatocellular carcinoma (HCC) i...
Article
A baby with complete atrioventricular block was born with a birth weight of 1403 g. Isoproterenol was ineffective and emergency pacing was required. Since transcutaneous pacing was ineffective and transvenous pacing was untenable due to small body size, transesophageal pacing was performed for 3.5 hours until permanent pacemaker implantation. There...
Article
Objectives The present study developed a new risk model for congenital heart surgery in Japan and determined the relationship between hospital procedural volume and mortality using the developed model. Methods We analyzed 47164 operations performed between 2013 and 2018 registered in the Japan Cardiovascular Surgery Database-Congenital and created...
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Congenital contractural arachnodactyly (CCA) is caused by pathogenic FBN2 variants; however, the contributions of copy number variations (CNVs) to CCA are still unknown. Here, we report on a familial case of CCA, in which a novel multiexon deletion of exons 35–39 in FBN2 was identified after simple CNV prediction. Congenital contractural arachnodac...
Article
In Japan, there has yet to be a report of a leadless pacemaker (LPM) implant in a pediatric patient. We present a case of a pediatric patient who underwent LPM implantation for various reasons. A 12-year-old girl suffered rejection for heart transplantation that was performed for the treatment of dilated cardiomyopathy 2 years after the procedure....
Article
Background:There has been no nationwide survey on the prognosis of pediatric restrictive cardiomyopathy (RCM) in Japan; therefore, this retrospective multicentered study was designed to investigate the long-term survival rate of pediatric patients with RCM in Japan. Methods and Results:A multicentered, retrospective observational study was performe...
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Background Among the several musculoskeletal manifestations in patients with Marfan syndrome, spinal deformity causes pain and respiratory impairment and is a great hindrance to patients’ daily activities. The present study elucidates the genetic risk factors for the development of severe scoliosis in patients with Marfan syndrome. Methods We retr...
Article
Aims The criteria for ‘good’ Fontan haemodynamics have been poorly defined in relation to long-term outcomes. The aim of this study was to identify the risk factors for mortality among haemodynamic parameters obtained early after the Fontan operation. Methods and results Clinical data of all perioperative survivors of the Fontan operation performe...
Article
There has been no multicenter study on the prognosis of pediatric hypertrophic cardiomyopathy (HCM) in Japan. Therefore, we conducted a retrospective multicenter observational study on the long-term survival rate in patients diagnosed with HCM under the age of 18 between 1990 and 2014. Twenty institutions participated. A total of 180 patients were...
Article
Background:There has been no nationwide survey on the prognosis of pediatric dilated cardiomyopathy (DCM) in Japan. Therefore, we designed this retrospective multicenter study to investigate the long-term survival rate in pediatric patients with DCM in Japan. Methods and Results:In this multicenter retrospective observational study, data were revie...
Article
Background: Investigation into the detection rate (DR) of congenital heart diseases (CHDs) in fetuses is important for the assessment of fetal cardiac screening systems. Objectives: We highlight issues of fetal cardiac screening in Japan. Methods: We performed an initial national survey of fetal diagnosis of CHDs from the data of the national...
Article
Recessive mutations in the Myosin regulatory light chain 2 (MYL2) gene are the cause of an infantile-onset myopathy, associated with fatal myocardial disease of variable macromorphology. We here present the first Japanese family affected with recessive MYL2 myopathy. Affected siblings manifested typical features and the proband's autopsy findings w...
Article
Background:Stent implantation for vascular stenosis associated with congenital heart diseases is commonly performed as an off-label procedure in Japan because there is no officially approved stent for any congenital heart disease. Methods and Results:We analyzed data from the Japanese Society of Congenital Interventional Cardiology Registry collect...
Article
Background:In Japan, the choice of pediatric medical devices is limited because of 2 “device lag” problems: Japan lags behind the USA and Europe in device development, and development of pediatric devices lags behind that of adult devices. We aimed to identify the problems with and impediments to pediatric medical device development as recognized b...
Article
Study design: A retrospective study of the prospective cohort. Objective: To demonstrate the accurate distribution of the severity of scoliosis in patients with Marfan syndrome, and to identify the predictive physical features for progression of scoliosis in Marfan syndrome. Summary of background data: To date, no study has unveiled the risk f...
Article
Background Left ventricular noncompaction (LVNC) is a hereditary cardiomyopathy, associated with high morbidity and mortality, but the role of genetics in cases of fetal-onset has not been fully evaluated. The goal of this study was to identify the genetic background in LVNC fetal-onset patients using next-generation sequencing (NGS). Methods Thir...
Article
Background:Although advances in cardiac surgery have led to an increased number of survivors with congenital heart disease (CHD), epidemiological data regarding the pregnancies and deliveries of patients with repaired CHD are scarce. Methods and Results:In this study, we retrospectively reviewed the clinical outcomes of pregnancies and deliveries o...
Article
Background: Role of specialist of pediatric critical care is significant, especially for management of congenital heart diseases because most critical cardiac patients have been cared by pediatric cardiologists or cardiovascular surgeons in Japan. Objects: To clarify future issues in the field of critical care in pediatric cardiology by investigati...
Article
Pulmonary valve stenosis (PVS) accounts for approximately 10% of all congenital heart defects. Echocardiography and right heart catheterization are the gold standards for diagnosis of PVS and for assessing disease severity and responsiveness to treatment. Recently, cardiac magnetic resonance imaging (cMRI) has been established as an important tool...
Article
A 59-year-old man received a single-lung transplantation due to interstitial pneumonitis. Severe anastomotic pulmonary artery stenosis (PAS) resulting in hypoxia and respiratory symptoms was found in the immediate postoperative period. A scintigraphy showed severe hypoperfusion of the left transplanted lung with 7% of the total pulmonary blood flow...
Article
Introduction/objectivesThe dosing of intravenous immunoglobulin (IVIG) therapy for Kawasaki disease (KD) has been a matter of debate for decades, with recent studies implicating that larger doses lead to better outcomes. Despite this, few have investigated post-IVIG infusion immunoglobulin G (IgG) levels in relation to outcomes of KD such as respon...
Article
Exercise intolerance is one of the major symptoms of chronic heart failure. Cardiopulmonary exercise testing (CPX) allows for the simultaneous study of responses to cardiovascular and ventilator systems to a known exercise stress through the measurement of gas exchange at the airway. During exercise, oxygen consumption and carbon dioxide production...
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Neonatal myocarditis is most often caused by enterovirus and has a high mortality of >50%. We report a case of neonatal enterovirus myocarditis. The patient was born at term with a birth weight of 2,637 g. He developed fever on perinatal day 2, and a gallop rhythm was detected by auscultation on day 7. Based on severe left ventricular dysfunction a...
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Background: Variants in the LZTR1 (leucine-zipper-like transcription regulator 1) gene (OMIM #600574) have been reported in recessive Noonan syndrome patients. In vivo evidence from animal models to support its causative role is lacking. Methods: By CRISPR-Cas9 genome editing, we generated lztr1-mutated zebrafish (Danio rerio). Analyses of histo...
Article
Background: Treatment of venous thromboembolism in children is based on data obtained in adults with little direct documentation of its efficacy and safety in children. The aim of our study was to compare the efficacy and safety of rivaroxaban versus standard anticoagulants in children with venous thromboembolism. Methods: In a multicentre, para...
Article
Neonatal myocarditis is most often caused by enterovirus and has a high mortality of >50%. We report a case of neonatal enterovirus myocarditis. The patient was born at term with a birth weight of 2,637 g. He developed fever on perinatal day 2, and a gallop rhythm was detected by auscultation on day 7. Based on severe left ventricular dysfunction a...
Article
Background: The precise mechanism of hyponatremia in Kawasaki disease (KD) remains elusive because assessment of volume status based on serial changes in body weight is lacking. Methods: Seventeen patients who were diagnosed with KD and hyponatremia (serum sodium levels < 135 mmol/L) were analyzed. Volume status was assessed based on serial chan...
Article
Introduction Liver fibrosis and cirrhosis are one of the critical complications in Fontan patients. However, there are no well-established non-invasive and quantitative techniques for evaluating liver abnormalities in Fontan patients. Intravoxel incoherent motion diffusion-weighted imaging with MRI is a non-invasive and quantitative method to evalu...
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Full-text available
The fibrogenic response in tissue-resident fibroblasts is determined by the balance between activation and repression signals from the tissue microenvironment. While the molecular pathways by which transforming growth factor-1 (TGF-β1) activates pro-fibrogenic mechanisms have been extensively studied and are recognized critical during fibrosis deve...
Article
Neonatal myocarditis has a high mortality of more than 50%. Enterovirus is the leading cause. We report a case of neonatal enterovirus myocarditis. The patient was born at term with a birth weight of 2637g. On day two of life, he developed fever, and on day 7 a gallop rhythm was auscultated. Based on severe left ventricular dysfunction and an eleva...
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Full-text available
Objective Heterotaxy syndrome is associated with complex cardiac malformations and cardiac conduction system abnormalities. Those with right atrial isomerism (RAI) have dual sinus nodes and dual atrioventricular nodes predisposing them to supraventricular tachycardia (SVT). Those with left atrial isomerism (LAI) lack a normal sinus node and are at...
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Reports indicate lower Down syndrome (DS) survival among females than among males in Australia, contrasting with female longevity in the general population. Using data on 1310 people with DS (626 females and 684 males) in Japan from five hospitals’ medical records and questionnaires completed by parents of people with DS, we investigated sex differ...
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Sepiapterin reductase deficiency (SRD), an extremely rare but treatable neurotransmitter disease, is an enzyme defect in the final step of tetrahydrobiopterin (BH 4 ) synthesis. ¹ Unlike other forms of BH 4 -deficient dopa-responsive dystonia, SRD uniquely does not manifest hyperphenylalaninemia and thus slips through detection by newborn screening...
Article
Aim Liver fibrosis caused by congestive hepatopathy has emerged as an important complication after Fontan procedure. We evaluated the utility of the hepatic vein (HV) waveform using Doppler ultrasound for identification of liver fibrosis in Fontan patients. Methods We investigated the HV waveforms in 41 Fontan patients and assessed correlations wi...
Article
Because of the rare co-occurrence, it remains a question whether cardiomyopathy is a true association of neurofibromatosis type 1. A boy with café-au-lait spots manifested restrictive cardiomyopathy. Whole exome sequencing confirmed the genetic diagnosis of neurofibromatosis and further identified a novel titin (TTN) missense variant. The significa...
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Candida prosthetic endocarditis (CPE) is an uncommon and fatal complication in adults with congenital heart disease. The current guidelines for the management of fungal endocarditis recommend a combination of surgical and medical therapy. However, it still remains uncertain when surgical management in CPE patients should be performed. Therefore, th...
Article
Background: Marfan syndrome can cause life-threatening aortic complications. We investigated the relationship between FBN1 genotype and severe aortopathy (aortic root replacement, type A dissections, and related death). Methods: We evaluated 248 patients with pathogenic or likely pathogenic FBN1 variants. The variants were classified as haploins...
Data
Data S1. End‐systolic pressure volume relationship based on maximum myocardial stiffness. Data S2. Relationship between Ea′ and pulmonary impedance. Data S3. R code for our single‐beat method. Figure S1. Relationship between conventional and novel indices of right ventricular–pulmonary arterial coupling. Figure S2. Estimated and measured Ees....
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Background: An accurate assessment of intrinsic right ventricular (RV) contractility and its relation to pulmonary arterial load is essential for the management of pulmonary hypertension. The pressure-volume relationship with load manipulation is the gold standard assessment used for this purpose, but its clinical application has been hindered by...
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Variants in TGFBR1 have been reported to induce two completely distinct diseases, namely Loeys-Dietz syndrome (LDS) and multiple self-healing squamous epithelioma (MSSE). However, detailed mechanisms underlying this effect remain unknown. We report a Japanese familial case of LDS with a novel splice donor site variant in TGFBR1 gene (c.973 + 1 G >...
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FBN1 mutations causing severe and early-onset Marfan syndrome (MFS) cluster in exons 24–32. Here, we report the case of a male patient with early-onset MFS who was born with arachnodactyly, annuloaortic ectasia (AAE), and aortic regurgitation (AR). At 4 years of age, he presented with progressive AAE and severe AR and was referred to our hospital....
Article
Background: Although early treatment of Kawasaki disease (KD) with intravenous immunoglobulin (IVIG) is expected to prevent coronary artery abnormalities, the effectiveness of IVIG within day 4 of illness remains to be determined. Methods: This was a multi-institutional, retrospective cohort study. Patients diagnosed with KD within day 4 were di...
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Full-text available
Background: The efficacy, pharmacokinetics, safety, and tolerability of bosentan (Tracleer® 32 mg, new dispersible tablet for pediatric use) for pulmonary arterial hypertension (PAH) were investigated in Japanese children. Methods: This was an open-label, multi-center, phase III, single-arm trial. Patients aged <15 years with PAH were administered...
Article
Purpose: Congenital heart disease (CHD) is the most common birth anomaly in Japan, occurring in approximately 10.6 of every 1,000 live births. Advancements in medical and surgical care have increased births by women diagnosed with CHD. The study's purpose was to examine the perceptions of pregnancy and childbirth among adolescent girls with CHD....
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We report the successful minimally invasive placement of a pericardial implantable cardioverter-defibrillator (ICD) in a 16-kg child. A transvenous ICD dual coil was advanced through a small subxiphoid incision and screwed into the oblique sinus pericardium under fluoroscopic guidance. An additional sense-pace lead was sutured onto the right ventri...
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Malan syndrome has recently been characterized to present Sotos-like phenotypes, such as intellectual disability and macrocephaly, with mutations in the NFIX gene. Herein, we report a 38-year-old patient with a novel single adenine insertion mutation in exon 2 of the NFIX gene (c.290_291insA). He developed early-onset thoracic aortic aneurysm and d...
Article
Background: Resistance to intravenous immunoglobulin (IVIG) therapy is a risk factor for coronary lesions in patients with Kawasaki disease (KD). Risk-adjusted initial therapy may improve coronary outcome in KD, but identification of high risk patients remains a challenge. This study aimed to develop a new risk assessment tool for IVIG-resistance...
Article
Objective: To investigate pregnancy outcomes, especially the risk of pregnancy-related aortic dissection (AD), in patients with Marfan syndrome (MFS) after prophylactic aortic root replacement (ARR). Design: Retrospective case series study. Setting: Tertiary perinatal care centre at a university hospital. Population: Pregnant women fulfillin...
Chapter
With more patients with hypoplastic left heart syndrome (HLHS) palliated through surgical revision and surviving into adulthood, long-term performance of the right-sided structures in the systemic position has become a clinical concern. Aortopathy, progressive dilation of aortic root, is one of such problems. Aortopathy in patients with HLHS is bec...
Article
Aims: We studied how Doppler-derived hemodynamic parameters in children change as the relative prosthetic mitral valve (PMV) size decreases with somatic growth and evaluated the diagnostic utility of the parameters for detecting PMV obstruction in children. Methods and results: We reviewed 26 echocardiographic examination results of 15 mechanica...
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Objective The end-systolic pressure–dimension relationship (ESPDR) and the preload recruitable stroke work (PRSW) relationship are load-insensitive measures of contractility, but their clinical application has been limited by the need to record multiple beats over a wide volume range. In this study, we therefore sought to validate a new method to c...
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Full-text available
Marfan syndrome (MFS) is an autosomal dominant heritable disorder of connective tissue that affects the cardiovascular, skeletal, ocular, pulmonary, and nervous systems and is usually caused by mutations in the FBN1 gene, which encodes fibrillin-1. MFS is traditionally considered to result from the structural weakness of connective tissue. However,...
Article
Background: Current Japanese transfer practices for adult congenital heart disease (ACHD) patients in pediatric departments are elucidated in this study. The focus was on 149 facilities (from the Japanese Society of Pediatric Cardiology and Cardiac Surgery Subspecialty Board and the Japanese Association of Children's Hospitals and Related Institut...
Article
The aortic root dilation in Tetralogy of Fallot (TOF) is a long-term clinical problem, because a severely dilated aorta can lead to aortic regurgitation, dissection, or rupture, which could be fatal and necessitate surgical intervention. However, the details of the mechanism of aortic root dilation are unclear. We have shown that aortic stiffness i...
Article
Objective: We tested the hypotheses that volume overload and cyanosis observed in the pre-Fontan single ventricular circulation are associated with increased ventricular fibrogenesis, that the Fontan procedure helps to reduce fibrogenesis, and that persistently increased fibrogenesis in the Fontan ventricle is associated with ventricular diastolic...
Article
We aimed to elucidate the relationship between severity of secondary mitral regurgitation and mitral valve geometry in children with dilated cardiomyopathy. The medical records of 16 children with dilated cardiomyopathy (median age, 1.2 years; range, 0.4–12.3 years) were reviewed. Mitral valve geometry was evaluated by measuring coaptation depth us...
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Background: The myocardial performance index (MPI) has emerged as a Doppler-derived index for global ventricular function capable of estimating combined systolic and diastolic performance. While several studies have reported its load-dependency, responses of the MPI to various hemodynamic changes have not been fully characterized.Methods and Resul...
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The L1264P and R1275L heterozygous mutations of the myosin heavy chain 11 (MYH11) gene, which are on the same allele, have been reported to cause thoracic aortic aneurysms and/or dissections (TAAD) complicated with patent ductus arteriosus (PDA); however, their contributions to the pathogenesis of TAAD/PDA have not been elucidated. Here we report t...