Clinical differences between children and adults with idiopathic and heritable pulmonary arterial hypertension

BACKGROUND

Although previous studies have demonstrated that paediatric pulmonary arterial hypertension remains distinct from that in adults, there are limited studies evaluating a direct comparison between children and adults. The aim of this head-to-head comparison study was to compare the gender, haemodynamic parameters, and prognosis between paediatric and adult pulmonary arterial hypertension.

METHODS AND RESULTS

We retrospectively assessed the clinical differences in 40 childhood-onset (under 20 years old) patients and 40 adult-onset patients with idiopathic and heritable pulmonary arterial hypertension who were followed up at two centres. There was no female predominance among patients with childhood-onset pulmonary arterial hypertension (child female: 42.5%, adult female: 80%). The percent of New York Heart Association functional class IV in adult-onset pulmonary arterial hypertension tended to be higher than those in childhood-onset pulmonary arterial hypertension (22.5 and 10%, respectively), although children had worse haemodynamic parameters at diagnosis (mean pulmonary artery pressure (children versus adults); median 65 mmHg versus 49 mmHg, p < 0.001). There was no significant difference in the event-free survival rate between the two groups (95% vs. 85%) during the follow-up period (median, 96 months; range, 1-120 months).

CONCLUSIONS

Although paediatric pulmonary arterial hypertension patients had worse haemodynamic parameters at diagnosis than adults, children survived as long as adults with appropriate therapeutic strategies.

Advantage of POLARx over ARCTIC FRONT ADVANCE PRO during pulmonary vein isolation for paroxysmal atrial fibrillation

Introduction

The electrical pulmonary vein (PV) isolation has been established as a curative therapy for paroxysmal atrial fibrillation (AF). Arctic Front™cryoballoon has been used worldwide for AF cryoablation. Recently, a new cryoballoon, POLARxTM CRYOABLATION system have been introduced, of which material of the balloon is softer and the N2O gas flow rate is higher.

Purpose

The aim was to investigate the procedural parameter and efficacy of POLARx comparing with Arctic Front.

Methods

This retrospective single center study included 101 consecutive patients who underwent paroxysmal AF ablation using cryoballoon at Keio University hospital from April 2021 to March 2022. The procedural data including the cryoballoon temperature and the number and duration of cryoablation were compared between POLARx (POLARx group) and ARCTIC FRONT ADVANCE PRO (AFA group). After the cryoablation, we added the radiofrequency application in order to maximize the isolated area when the voltage was remained inside PV (Figure 1). The necessities of the additional radiofrequency applications were also compared.

Results

In the present study, 64 patients in AFA group and 37 patients in POLARx group were analyzed. POLARx group included younger population and less females (62.8±9.9 vs 67.5±9.4 year of age, P=0.02; 13.5 vs 32.8%, P=0.04). There was no significant difference in comorbidities and examination data such as left atrium diameter or brain natriuretic peptide level. The minimal cryoballoon temperatures reached in POLARx group were lower than AFA group (−59.3±6.2 vs −47.7±7.5°C, P&lt;0.01). No difference was found in the total number and duration of cryoablation and the time to isolate PV (6.1±2.1 vs 5.9±1.6, P=0.69; 790.2±256.1 vs 776.1±235.0 sec, P=0.69; 41.8±21.3 vs 47.1±29.6 sec, P=0.44, respectively). With regard to individual PVs, the total number and duration were tended to be larger at right superior PV in POLARx group (1.9±1.1 vs 1.4±0.7, P=0.01; 231.8±123.8 vs 193.2±83.0 sec, P=0.07), while there was no significant difference at the other PVs. The rate of successful PV isolation by a single cryo-application was not different between AFA and POLARx group (54.3 vs 61.4%, P=0.17). The additional radiofrequency applications were more frequent in AFA group (14.8 vs. 4.9%, P=0.003). There was a significant difference at right inferior PV (32.8 vs 8.1%, P=0.01), while not at left superior PV, left inferior PV and right superior PV (9.4 vs 2.9%, P=0.42; 9.4 vs 5.7%, P=0.71; 7.8 vs 2.7%, P=0.41). Phrenic nerve injury was occurred 1 case in both group and esophageal ulcer was occurred in 1 case in AFA group. No other complication including cardiac tamponade was occurred.

Conclusion

The total number and duration of cryoablation were not significantly different between AFA and POLARx group, except for right superior PV. There was an advantage in largely isolating right inferior PV in POLARx group comparing with AFA group.

Funding Acknowledgement

Type of funding sources: None.

Outcomes of idiopathic pulmonary arterial hypertension in Japanese children: a retrospective cohort study

Recently, targeted therapy has been developed for idiopathic pulmonary arterial hypertension (IPAH). Studies evaluating the prognosis of IPAH have been conducted in adults. However, there is no nationwide survey of pediatric patients with IPAH regarding the long-term prognosis in Japan. Therefore, we investigated the clinical outcomes of Japanese pediatric patients with IPAH and risk factors for a poor prognosis. This multi-center, retrospective cohort study included pediatric patients with IPAH under the age of 15 years, who were gleaned from the nationwide network of Japanese Society of Pediatric Cardiology and Cardiac Surgery (JSPCCS). The questionnaire was sent to members of JSPCCS in 2015. Patients who were diagnosed with IPAH from 1994 to 2014 were included. The primary endpoint was death or lung transplantation. Ninety-five patients were finally enrolled. Both the mean age at diagnosis and the mean follow-up duration were 7 years. Ninety-five percent of patients had received targeted therapy for IPAH during follow-up. The overall 1, 3, 5, and 10-year event free rate, estimated using Kaplan-Meier survival estimate, was 96, 91, 83, and 74%, respectively. The prognosis was significantly poorer in patients with increased right ventricular systolic pressure (RVp), mean pulmonary artery pressure (mPAP) (≥ 52 mmHg), cardiothoracic ratio (≥ 55%), and levels of B-type natriuretic peptide (BNP) during follow-up (≥ 300 pg/mL) than in those without these parameters. In conclusion, in Japanese children with IPAH, the event-free rate for death or lung transplantation was found to be good. Greater RVp, mPAP, BNP levels during follow-up, and cardiothoracic ratio may be predictive indicators for a poor prognosis.

Pregnancy and Delivery in Patients With Repaired Congenital Heart Disease - A Retrospective Japanese Multicenter Study

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 of women with repaired CHD. Overall, 131 women with repaired CHD were enrolled and there were 269 gestations. All patients were classified as New York Heart Association (NYHA) Class I or II. The prevalence of cesarean sections was higher in patients with (CyCHD) than without (AcyCHD) a past history of cyanosis (51% vs. 19%, respectively; P<0.01). There were 228 offspring from 269 gestations and the most prevalent neonatal complication was premature birth (10%), which was more frequent in the CyCHD than AcyCHD group (15.7% vs. 5.6%, respectively; P<0.01). Five maternal cardiac complications during delivery were observed only in the CyCHD group (8%); these were classified as NYHA Class II and none was fatal.

CONCLUSIONS

Delivery was successful in most women with repaired CHD who were classified as NYHA Class I or II, although some with CyCHD and NYHA Class II required more attention. Cesarean sections were more common in the CyCHD than AcyCHD group, and CyCHD may be a potential risk for preterm deliveries.

Change of the pulmonary vein anatomy after cryoballoon ablation reflecting left atrial reverse remodeling

Background

Cryoballoon ablation (CBA) is a widely used procedure for atrial fibrillation (AF). However, the anatomical change of pulmonary veins (PVs) and the risk factors of PV stenosis is less clear. We aimed to decipher the prevalence and the predictive factors for PV stenosis after CBA.

Methods

We analyzed the data of 320 PVs from 80 patients who underwent CBA for AF (age: 62±10 years, 59 males, 75 paroxysmal AF). All patients underwent pre- and post-procedural cardiac computed tomography (mean 6.7±3.3 months after ablation). We defined the PV stenosis when the cross sectional area of PV was less than 50% compared with that of PV before the CBA.

Results

The average cross sectional PV area decreased significantly after CBA (pre- vs. post-CBA; 2.4±1.0cm2 vs. 2.3±1.1cm2, P&lt;0.001), whereas the volume of left atrium (LA) also decreased significantly (pre- vs. post-CBA; 75.0±23.2cm3 vs. 70.7±21.9cm3, P&lt;0.001). There was a weak but significant correlation between the reduction rate of PV area and that of LA volume (Pearson's correlation coefficient 0.411, p&lt;0.001). Only 6 PV stenosis were revealed, in which area reduction of more than 75% and 50–75% were observed in 2 PVs and 4 PVs, respectively. The incidence of PV stenosis was greater in female (male vs. female; 0.8% vs. 4.8%, P=0.043) and tend to be frequent in left PVs (left PVs vs. right PVs; 3.1% vs. 0.6%: P=0.107). Moreover, patients who developed PV stenosis tended to have lower weight and shorter height (PV stenosis group vs. non-PV stenosis group; 58.2±12.4kg vs. 67.7±13.0kg: P=0.078, 161.2±9.1cm vs. 167.2±8.8cm: P=0.094). There were no significant differences in the number of freezing, minimum temperature and total freezing time between PV stenosis group and non-PV stenosis group.

Conclusions

The ostial PV area decreased significantly but little after CBA, possibly due to LA reverse remodeling. The PV stenosis was more common in women and tend to be frequent in left PVs, lower weight, and shorter height patients, though severe stenosis after CBA was not observed in this study.

Funding Acknowledgement

Type of funding source: None

Lipidomics links oxidized phosphatidylcholines and coronary arteritis in Kawasaki disease

AIMS

Coronary arteritis is a life-threatening complication that may arise in the acute stage of Kawasaki disease (KD), the leading cause of systemic vasculitis in childhood. Various microorganisms and molecular pathogens have been reported to cause KD. However, little is known about the key molecules that contribute to the development of coronary arteritis in KD.

METHODS AND RESULTS

To identify causative molecules for coronary arteritis in KD, we prospectively recruited 105 patients with KD and 65 disease controls in four different parts of Japan from 2015 to 2018. During this period, we conducted lipidomics analyses of their sera using liquid chromatography-mass spectrometry (LC-MS). The comprehensive LC-MS system detected a total of 27 776 molecules harbouring the unique retention time and m/z values. In the first cohort of 57 KD patients, we found that a fraction of these molecules showed enrichment patterns that varied with the sampling region and season. Among them, 28 molecules were recurrently identified in KD patients but not in controls. The second and third cohorts of 48 more patients with KD revealed that these molecules were correlated with inflammatory markers (leucocyte counts and C-reactive proteins) in the acute stage. Notably, two of these molecules (m/z values: 822.55 and 834.59) were significantly associated with the development of coronary arteritis in the acute stage of KD. Their fragmentation patterns in the tandem MS/MS analysis were consistent with those of oxidized phosphatidylcholines (PCs). Further LC-MS/MS analysis supported the concept that reactive oxygen species caused the non-selective oxidization of PCs in KD patients. In addition, the concentrations of LOX-1 ligand containing apolipoprotein B in the plasma of KD patients were significantly higher than in controls.

CONCLUSION

These data suggest that inflammatory signals activated by oxidized phospholipids are involved in the pathogenesis of coronary arteritis in KD. Because the present study recruited only Japanese patients, further examinations are required to determine whether oxidized PCs might be useful biomarkers for the development of coronary arteritis in broad populations of KD.

Changes in cardiac function after renal transplantation in children: Significance of pre-transplantation left ventricular hypertrophy

LVH is a significant risk factor for the development of cardiovascular morbidity. However, few studies have evaluated the changes in cardiac function that occur in pediatric patients with ESRD undergoing RTx. Therefore, we assessed the changes in parameters associated with LVH in children within the first year after RTx. We retrospectively evaluated patients aged < 18 years who underwent initial RTx from April 2014 to December 2016. The patients were divided into 2 groups according to the presence of LVH before RTx. Clinical, biochemical, and echocardiographic parameters including the LVMI before and 1 year after RTx were evaluated in both groups. Twenty-six patients were included in this study. Seven of the 26 patients had LVH before RTx. Among the echocardiographic parameters, the LVMI was significantly improved 1 year after RTx in the initial LVH group (57.79 ± 11.86 vs 42.20 ± 6.03 g/cm^2.7 , P = .018), while no change was observed in the initial non-LVH group (32.66 ± 7.52 vs 35.17 ± 12.86 g/cm^2.7 , P = .376). Improvement of the ejection fraction was also observed only in the initial LVH group (66.5% ± 5.3% vs 72.2% ± 5.2%, P = .042). Children who had LVH before RTx showed significant improvements in the LVMI and ejection fraction even within 1 year after RTx. To minimize aggravation of cardiac function, early RTx should be considered for patients with LVH.

Efficacy of primary treatment with immunoglobulin plus ciclosporin for prevention of coronary artery abnormalities in patients with Kawasaki disease predicted to be at increased risk of non-response to intravenous immunoglobulin (KAICA): a randomised controlled, open-label, blinded-endpoints, phase 3 trial

BACKGROUND

Genetic studies have indicated possible involvement of the upregulated calcium-nuclear factor of activated T cells pathway in the pathogenesis of Kawasaki disease. We aimed to assess safety and efficacy of ciclosporin, an immunosuppressant targeting this pathway, for protection of patients with Kawasaki disease against coronary artery abnormalities.

METHODS

We did a randomised, open-label, blinded endpoints trial involving 22 hospitals in Japan between May 29, 2014, and Dec 27, 2016. Eligible patients predicted to be at higher risk for intravenous immunoglobulin (IVIG) resistance were randomly assigned to IVIG plus ciclosporin (5 mg/kg per day for 5 days; study treatment) or IVIG (conventional treatment) groups, stratified by risk score, age, and sex. The primary endpoint was incidence of coronary artery abnormalities using Japanese criteria during the 12-week trial, assessed in participants who received at least one dose of study drug and who visited the study institution at least once during treatment. This trial is registered to Center for Clinical Trials, Japan Medical Association, number JMA-IIA00174.

FINDINGS

We enrolled 175 participants. One patient withdrew consent after enrolment and was excluded and one patient (in the study treatment group) was excluded from analysis because of lost echocardiography data. Incidence of coronary artery abnormalities was lower in the study treatment group than in the conventional treatment group (12 [14%] of 86 patients vs 27 [31%] of 87 patients; risk ratio 0·46; 95% CI 0·25-0·86; p=0·010). No difference was found in the incidence of adverse events between the groups (9% vs 7%; p=0·78).

INTERPRETATION

Combined primary therapy with IVIG and ciclosporin was safe and effective for favourable coronary artery outcomes in Kawasaki disease patients who were predicted to be unresponsive to IVIG.

FUNDING

Japan Agency for Medical Research and Development (grant CCT-B-2503).

Association of Severity of Coronary Artery Aneurysms in Patients With Kawasaki Disease and Risk of Later Coronary Events

IMPORTANCE

Few studies with sufficient statistical power have shown the association of the z score of the coronary arterial internal diameter with coronary events (CE) in patients with Kawasaki disease (KD) with coronary artery aneurysms (CAA).

OBJECTIVE

To clarify the association of the z score with time-dependent CE occurrence in patients with KD with CAA.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter, collaborative retrospective cohort study of 44 participating institutions included 1006 patients with KD younger than 19 years who received a coronary angiography between 1992 and 2011.

MAIN OUTCOMES AND MEASURES

The time-dependent occurrence of CE, including thrombosis, stenosis, obstruction, acute ischemic events, and coronary interventions, was analyzed for small (z score, <5), medium (z score, ≥5 to <10; actual internal diameter, <8 mm), and large (z score, ≥10 or ≥8 mm) CAA by the Kaplan-Meier method. The Cox proportional hazard regression model was used to identify risk factors for CE after adjusting for age, sex, size, morphology, number of CAA, resistance to initial intravenous immunoglobulin (IVIG) therapy, and antithrombotic medications.

RESULTS

Of 1006 patients, 714 (71%) were male, 341 (34%) received a diagnosis before age 1 year, 501 (50%) received a diagnosis between age 1 and 5 years, and 157 (16%) received a diagnosis at age 5 years or older. The 10-year event-free survival rate for CE was 100%, 94%, and 52% in men (P < .001) and 100%, 100%, and 75% in women (P < .001) for small, medium, and large CAA, respectively. The CE-free rate was 100%, 96%, and 79% in patients who were not resistant to IVIG therapy (P < .001) and 100%, 96%, and 51% in patients who were resistant to IVIG therapy (P < .001), respectively. Cox regression analysis revealed that large CAA (hazard ratio, 8.9; 95% CI, 5.1-15.4), male sex (hazard ratio, 2.8; 95% CI, 1.7-4.8), and resistance to IVIG therapy (hazard ratio, 2.2; 95% CI, 1.4-3.6) were significantly associated with CE.

CONCLUSIONS AND RELEVANCE

Classification using the internal diameter z score is useful for assessing the severity of CAA in relation to the time-dependent occurrence of CE and associated factors in patients with KD. Careful management of CE is necessary for all patients with KD with CAA, especially men and IVIG-resistant patients with a large CAA.

Infliximab for the Treatment of Refractory Kawasaki Disease: A Nationwide Survey in Japan

OBJECTIVE

To assess the safety and efficacy of infliximab (IFX) for the treatment of patients with Kawasaki disease (KD).

STUDY DESIGN

This was a nationwide survey of 274 Japanese institutions exploring how IFX was used to treat patients with KD. The patients' sex, age, treatment course, pre- and post-IFX therapy blood test results, coronary artery lesions (CALs), and adverse events (AEs) were evaluated.

RESULTS

We analyzed 434 patients with KD who received IFX between March 2005 and November 2014. The median age at onset was 33 months (range 1-138), and 66 patients (15.2%) were under 1 year old. In all cases, IFX was administered as additional treatment. The median days of illness at the initiation of IFX was 9 days. In 275 patients (63.4%), IFX was administered as third-line treatment, and in 106 patients (24.4%), IFX was administered as fourth-line treatment. Single dose IFX 5 mg/kg was administered to 412 patients (94.9%). After IFX, 363 patients (83.6%) became afebrile within 2 days, and the white blood cell count, percentage of neutrophils, and serum C-reactive protein levels significantly decreased (P < .001), although 119 patients (27.4%) received additional treatment. Before IFX, 132 patients (30.4%) had already developed CALs. In patients without CALs before IFX, 31 patients (10.3%) newly developed CAL after IFX, whereas 32 patients (24.2%) with CAL before IFX showed increased CAL severity. Eighty AEs were observed in 69 patients (15.9%); however, serious AEs were few and reversible.

CONCLUSIONS

IFX might be an effective and tolerable treatment for refractory KD.

Clinical Impact of Main Pulmonary Artery Dilatation on Outcome in Pediatric Idiopathic and Heritable Pulmonary Arterial Hypertension

BACKGROUND

Few studies have investigated the clinical impact of pulmonary artery (PA) dilatation on outcomes in pediatric pulmonary arterial hypertension (PAH).Methods and Results:This study investigated the clinical outcomes of idiopathic or heritable PAH in 66 children aged <18 years at diagnosis. Main PA/thorax (MPA/T) ratio was measured on chest radiography in PAH patients. Patients were divided into 2 groups based on MPA/T ratio, and compared with a control group of 166 age- and gender-matched healthy children. Group A had higher MPA/T ratio than normal, and group B had normal MPA/T ratio. Composite outcomes included cardiac death, lung transplantation, and hospitalization due to heart failure. Group A consisted of 27 patients and group B, 39 patients. At diagnosis, group A had significantly higher brain natriuretic peptide (BNP), cardiothoracic ratio, PA pressure, and pulmonary vascular resistance index compared with group B. The number of patients with New York Heart Association (NYHA) functional class III and IV was significantly higher in group A than in group B. Cumulative event-free survival rate was significantly lower in group A.

CONCLUSIONS

MPA dilatation correlated with BNP, NYHA functional class, and hemodynamics with regard to disease severity, and may be a potential prognostic factor in pediatric idiopathic and heritable PAH.

Low risk of treatment resistance in Down syndrome with Kawasaki disease

BACKGROUND

A Japanese nationwide survey has reported that Down syndrome (DS) is a less-frequently occurring comorbidity in Kawasaki disease (KD). Although altered immune responses are frequently observed in DS, no studies have focused on the treatment response and risk for coronary artery abnormalities (CAA) in DS patients with KD. The aim of this study was therefore to evaluate the clinical manifestations, treatment response and prevalence of CAA in DS with KD.

METHODS

We retrospectively reviewed the medical records of DS patients with KD from 2005 through 2012. The survey questionnaires were sent to facilities nationwide, and clinical data regarding KD in DS were collected. A control group consisted of non-DS patients with KD who were managed at Toho University.

RESULTS

Of the 94 233 children diagnosed with acute KD from 2005 to 2012, 16 children with acute KD also had DS (0.017%). The DS-KD patients were significantly older than the non-DS patients (median, 8 years vs 1 year, P < 0.05, respectively). Half of the DS patients had incomplete KD. Although 50% of the DS children were at high risk of immunoglobulin resistance, all children responded to initial treatment and none had CAA.

CONCLUSIONS

All DS-KD patients responded to initial i.v. immunoglobulin (IVIG) or aspirin despite having a high risk of IVIG resistance, and none of the DS patients had CAA. This suggests that the risk of treatment resistance and development of CAA may be not higher in DS patients with acute KD.

[Anti TNF-α (infliximab) treatment for intravenous immunoglobulin (IVIG) resistance patients with acute Kawasaki disease the effects of anticytokine therapy]

Among the patients with acute Kawasaki disease treated with intravenous immunoglobulin (IVIG), 10-20 % demonstrate resistance or incomplete effects. Cardiac complication such as the coronary arterial aneurysm is frequent in these patients. For patients with IVIG-resistance, we have surveyed the efficacy and safety of anti-cytokine therapy with use of infliximab (Remicade), chimera type anti TNF-α agent, for children. After May, 2005, Remicade has been used in >500 pediatric patients in whom IVIG and intravenous methylprednisolone pulse therapy did not show significant effects. The efficacy and safety of Remicade on patients with IVIG-resistant Kawasaki disease has been observed but 10~20 % of patients was Remicade-resistant. Re-treatment with IVIG or steroids was also effective. The efficacy of Remicade for reducing the fever duration, CRP, WBC counts was promising, but reduction of the incidence of coronary aneurysm was not confirmed. Randomized clinical trial will be needed.

Evaluation of circulating proteins and hemodynamics towards predicting mortality in children with pulmonary arterial hypertension

BACKGROUND

Although many predictors have been evaluated, a set of strong independent prognostic mortality indicators has not been established in children with pediatric pulmonary arterial hypertension (PAH). The aim of this study was to identify a combination of clinical and molecular predictors of survival in PAH.

METHODS

This single-center, retrospective cohort study was performed from children with PAH between 2001 and 2008 at Children's Hospital Colorado. Blood samples from 83 patients (median age of 8.3 years-old) were obtained. We retrospectively analyzed 46 variables, which included 27 circulating proteins, 7 demographic variables and 12 hemodynamic and echocardiographic variables for establishing the best predictors of mortality. A data mining approach was utilized to evaluate predictor variables and to uncover complex data structures while performing variable selection in high dimensional problems.

RESULTS

Thirteen children (16%) died during follow-up (median; 3.1 years) and survival rates from time of sample collection at 1 year, 3 years and 5 years were 95%, 85% and 79%, respectively. A subset of potentially informative predictors were identified, the top four are listed here in order of importance: Tissue inhibitors of metalloproteinases-1 (TIMP-1), apolipoprotein-AI, RV/LV diastolic dimension ratio and age at diagnosis. In univariate analysis, TIMP-1 and apolipoprotein-AI had significant association with survival time (hazard ratio [95% confidence interval]: 1.25 [1.03, 1.51] and 0.70 [0.54-0.90], respectively). Patients grouped by TIMP-1 and apolipoprotein-AI values had significantly different survival risks (p<0.01).

CONCLUSION

Important predictors of mortality were identified from a large number of circulating proteins and clinical markers in this cohort. If confirmed in other populations, measurement of a subset of these predictors could aid in management of pediatric PAH by identifying patients at risk for death. These findings also further support a role for the clinical utility of measuring circulating proteins.

Current challenges in pediatric pulmonary hypertension

Pulmonary arterial hypertension (PAH) in the pediatric population is associated with a variety of underlying diseases and causes, significantly morbidity and mortality. In the majority of patients, PAH in children is idiopathic or associated with congenital heart disease (CHD), with pulmonary hypertension (PH) associated with connective tissue disease, a rare cause in children. Classification of pediatric PH has generally followed the WHO classification, but recognition of the importance of fetal origins of PH and developmental abnormalities have led to the formation of a new pediatric-specific classification. Incidence data from the Netherlands has revealed an annual incidence and point prevalence of 0.7 and 4.4 for idiopathic PAH and 2.2 and 15.6 for associated pulmonary arterial hypertension-CHD cases per million children. Although the treatment with new selective pulmonary vasodilators offers hemodynamic and functional improvement in pediatric populations, the treatments in children largely depend on results from evidence-based adult studies and experience of clinicians treating children. A recent randomized clinical trial of sildenafil and its long-term extension has led to disparate recommendations in the United States and Europe.

Clinical features of adult patients with Eisenmenger's syndrome in Japan and Korea

BACKGROUND

There are few articles on mortality and morbidity of adult patients with Eisenmenger's syndrome (ES) in the current era when disease targeting therapy (DTT) has been available.

METHODS AND RESULTS

198 patients (a median age 35 years, 64% female) with ES who visited the 16 participating institutes in Japan and Korea from 1998 to 2009 were enrolled. Clinical data during adulthood were collected from each institutional chart and analyzed centrally. During a median follow-up of 8 years, 30 patients died including 14 sudden deaths. 89 patients took oral medication of DTT and clinical improvement was observed in 54 of them. However, survival rate in patients taking DTT was not different from those without (87% vs 84%, p=0.55). When the clinical data in between first and last clinic visits were compared in 85 patients, the patients with NYHA >/=III increased from 24% to 48% (p<0.001), SpO2 decreased from 89% to 85% (p=0.008) and hematocrit increased from 51.4% to 52.9% (p=0.04). Non-survivors had poorer NYHA function class, lower body weight (BW), lower body mass index (BMI), and higher serum level of Cr at the first visits than survivors.

CONCLUSIONS

Long term survival and clinical status of adult patients with ES remains unsatisfactory even in the current era of DTT. Poor NYHA functional class, low BW, low BMI and high serum level of Cr were related to mortality. DTT therapy improved clinical status in many patients with Eisenmenger's syndrome, but no significant impact on survival could be shown.

Coronary artery outcomes among children with Kawasaki disease in the United States and Japan

OBJECTIVE

It has been claimed that the aneurysm rate for Kawasaki disease (KD) patients in Japan is lower than in the U.S. However it has been difficult to compare coronary artery (CA) outcomes between the two countries because of different definitions for CA abnormalities. Therefore, we compared CA internal diameters between Japanese and U.S. KD patients using standard definitions and methods.

STUDY DESIGN

We retrospectively reviewed CA outcomes in 1082 KD patients from 2 centers in the U.S. and 3 centers in Japan and compared Z-max scores (maximum internal diameter for the left anterior descending or right coronary artery expressed as standard deviation units from the mean (Z-score) normalized for body surface area) obtained within 12 weeks after onset and calculated using two different regression equations from Canada (Dallaire) and Japan (Fuse). We defined a Z-max of < 2.5 as normal and a Z-max of ≥ 10 as giant aneurysm.

RESULT

The median Z-max for the U.S. and Japanese subjects was 1.9 and 2.3 SD units, respectively (p < 0.001). There was no significant difference in rates of patients with Z-max ≥ 5.0 between the countries. In a multivariable model adjusting for age, sex, and treatment response, being Japanese was still associated with a higher Z-max score.

CONCLUSION

Previously reported differences in aneurysm rates between Japan and the U.S. likely resulted from use of different definitions and nomenclature. Adoption of Z-scores as a standard for reporting CA internal diameters will allow meaningful comparisons among different countries and will facilitate international, collaborative clinical trials.

Acute pulmonary vasodilator testing with inhaled treprostinil in children with pulmonary arterial hypertension

Acute pulmonary vasodilator testing (AVT) is essential to determining the initial therapy for children with pulmonary arterial hypertension (PAH). This study aimed to report the initial experience with inhaled treprostinil used for AVT in children with PAH and to evaluate the hemodynamic change after inhaled treprostinil compared with inhaled nitric oxide. This prospective cohort study was designed for 13 children who underwent AVT with inhaled treprostinil or oxygen plus inhaled nitric oxide (iNO) during catheterization. Inhaled treprostinil was delivered during cardiac catheterization by adapting the Optineb ultrasonic nebulizer via either a flow-inflating bag or the manual mode of the anesthesia system. The median age of the patients was 10 years (range 4-17 years). The etiologies of PAH included idiopathic PAH and associated PAH. All the patients tolerated inhaled treprostinil without marked clinical worsening and received six or nine breaths (36 or 54 μg) of treprostinil. The median of the total treprostinil doses was 1.53 μg/kg (range 0.71-2.89 μg/kg). Inhaled treprostinil was administrated via an endotracheal tube (n = 8), anesthesia mask (n = 3), or laryngeal mask airway (n = 2). Inhaled nitric oxide (iNO) and inhaled treprostinil significantly decreased the mean pulmonary artery pressure and the pulmonary vascular resistance index compared with baseline. Three adverse events were reported after inhaled treprostinil, including cough and mild to moderate hypotension with higher doses. All adverse events resolved without any intervention. This study report is the first to describe the use of inhaled treprostinil for AVT in children with PAH. In this small pediatric cohort, inhaled treprostinil was effectively delivered and well tolerated and may be useful for AVT.

Clinical safety, pharmacokinetics, and efficacy of ambrisentan therapy in children with pulmonary arterial hypertension

Recent trials in adult PAH revealed the efficacy of ambrisentan. However, in children with PAH, the clinical safety and pharmacokinetics of ambrisentan has not been well studied. Our aim was to investigate the clinical safety, pharmacokinetics, tolerability, and efficacy of endothelin receptor antagonist therapy with ambrisentan in children with pulmonary arterial hypertension (PAH). This retrospective cohort study provides clinical data from pediatric patients with PAH receiving ambrisentan as add-on therapy or transition from bosentan. Safety included evaluation of adverse events including aminotransferase abnormalities. The clinical impact was evaluated by improvement from baseline in clinical variables. A total of 38 pediatric patients with PAH received ambrisentan. Fifteen of 38 patients were switched from bosentan to ambrisentan. The remaining 23 children were treated with ambrisentan as an add-on therapy due to disease progression. In both transition and add-on cases, mean pulmonary artery pressure significantly improved (transition; 55 ± 18 vs. 45 ± 20 mmHg, n = 13, P = 0.04, add-on; 52 ± 17 vs. 45 ± 19 mmHg, n = 13, P = 0.03) during the follow-up. World Health Organization functional class improved in 31% of patients, but one patient required an atrial septostomy due to disease progression during the follow-up period (median, range; 20, 4-44 months). Five patients (13%) discontinued ambrisentan due to severe headache, lack of clinical efficacy, or near syncope. Ten patients (26%) had side effects associated with ambrisentan treatment, including nasal congestion, headache, and flushing. However, no patients had aminotransferase abnormalities and there were no deaths after initiation of ambrisentan during follow-up. Pharmacokinetics were evaluated in sixteen children treated with ambrisentan from 2.5 mg to 10.0 mg; the mean peak plasma concentration was 738 ± 452 ng/ml, mean time to peak plasma concentration was 3.2 ± 2.1 hours, and mean area under the curve plasma concentration was 6657 ± 4246 ng·hour/ml. In conclusion, initial experience with ambrisentan in children suggests that treatment is safe with similar pharmacokinetics to those in adults and may improve PAH in some children.

Tissue Doppler imaging predicts adverse outcome in children with idiopathic pulmonary arterial hypertension

OBJECTIVE

To evaluate the clinical utility of tissue Doppler imaging (TDI) in assessment of disease severity and prognostic value in children with idiopathic pulmonary arterial hypertension (PAH).

STUDY DESIGN

A prospective study was performed to evaluate TDI velocities (systolic myocardial velocity, early diastolic myocardial relaxation velocity [Em], late diastolic myocardial velocity associated with atrial contraction), brain natriuretic peptide, New York Heart Association (NYHA) functional class, and hemodynamics in 51 children (mean age; 11.6 years) with idiopathic PAH. Fifty-one healthy children with comparable demographics served as controls.

RESULTS

Em, Em/late diastolic myocardial velocity associated with atrial contraction ratio, and systolic myocardial velocity at mitral annulus, septum, and tricuspid annulus in PAH were significantly reduced compared with controls. Tricuspid Em had significant inverse correlations with plasma brain natriuretic peptide levels (r = -0.60, P < .001), right ventricular end-diastolic pressure (r = -0.79, P < .001), and mean pulmonary arterial pressure (r = -0.67, P < .001). Statistically significant differences were observed in tricuspid Em between NYHA functional class II vs combined III and IV (mean and SD; 11.9 ± 4.2 cm/s vs 8.2 ± 3.6 cm/s, respectively, P = .002). Cumulative event-free survival rate was significantly lower when tricuspid Em was ≤8 cm/s (log-rank test, P < .001)

CONCLUSIONS

Tricuspid Em velocity correlated with NYHA functional class as disease severity and may serve as a useful prognostic marker in children with idiopathic PAH. The present study is the initial report to evaluate TDI velocities against midterm outcome variables in a relatively large pediatric PAH population.

Effectiveness and safety of inhaled treprostinil for the treatment of pulmonary arterial hypertension in children

The introduction of prostanoid therapy has revolutionized the treatment of pulmonary arterial hypertension (PAH). However, continuous intravenous prostacyclin infusion poses significant risks and challenges, particularly in children. Inhaled treprostinil has been shown to be safe and efficacious in adults. This study describes the safety and efficacy of inhaled treprostinil in children with PAH. A retrospective analysis of 29 children treated with inhaled treprostinil for ≥6 weeks was performed. Effects of inhaled treprostinil on exercise capacity, functional class, and echocardiographic and hemodynamic data were evaluated. Adverse events were documented. Patients received 3 to 9 breaths (6 μg/breath) of inhaled treprostinil 4 times/day. All were receiving background PAH therapy; 12 had previously received parenteral prostanoid. Inhaled treprostinil was discontinued in 4 patients because of symptoms including cough and bronchospasm (n = 3) and progression of PAH (n = 1). Mild side effects including cough (n = 9) and sore throat (n = 6) did not require discontinuation of therapy. World Health Organization functional class improved in 19 and was unchanged in 10; exercise capacity significantly improved with the 6-minute walk distance, improving on follow-up from 455.7 ± 71.5 to 498 ± 70 m (p = 0.01) and peak oxygen consumption increasing from 25.5 ± 10.2 to 27.4 ± 10 (p = 0.04). In conclusion, inhaled treprostinil was associated with improvement in exercise capacity and World Health Organization functional class when added to background targeted PAH therapy in children and had an acceptable safety profile. Based on these early data, further study of inhaled treprostinil appears warranted in pediatric patients with PAH.

Efficacy of immunoglobulin plus prednisolone for prevention of coronary artery abnormalities in severe Kawasaki disease (RAISE study): a randomised, open-label, blinded-endpoints trial

BACKGROUND

Evidence indicates that corticosteroid therapy might be beneficial for the primary treatment of severe Kawasaki disease. We assessed whether addition of prednisolone to intravenous immunoglobulin with aspirin would reduce the incidence of coronary artery abnormalities in patients with severe Kawasaki disease.

METHODS

We did a multicentre, prospective, randomised, open-label, blinded-endpoints trial at 74 hospitals in Japan between Sept 29, 2008, and Dec 2, 2010. Patients with severe Kawasaki disease were randomly assigned by a minimisation method to receive either intravenous immunoglobulin (2 g/kg for 24 h and aspirin 30 mg/kg per day) or intravenous immunoglobulin plus prednisolone (the same intravenous immunoglobulin regimen as the intravenous immunoglobulin group plus prednisolone 2 mg/kg per day given over 15 days after concentrations of C-reactive protein normalised). Patients and treating physicians were unmasked to group allocation. The primary endpoint was incidence of coronary artery abnormalities during the study period. Analysis was by intention to treat. This trial is registered with the University Hospital Medical Information Network clinical trials registry, number UMIN000000940.

FINDINGS

We randomly assigned 125 patients to the intravenous immunoglobulin plus prednisolone group and 123 to the intravenous immunoglobulin group. Incidence of coronary artery abnormalities was significantly lower in the intravenous immunoglobulin plus prednisolone group than in the intravenous immunoglobulin group during the study period (four patients [3%] vs 28 patients [23%]; risk difference 0·20, 95% CI 0·12-0·28, p<0·0001). Serious adverse events were similar between both groups: two patients had high total cholesterol and one neutropenia in the intravenous immunoglobulin plus prednisolone group, and one had high total cholesterol and another non-occlusive thrombus in the intravenous immunoglobulin group.

INTERPRETATION

Addition of prednisolone to the standard regimen of intravenous immunoglobulin improves coronary artery outcomes in patients with severe Kawasaki disease in Japan. Further study of intensified primary treatment for this disease in a mixed ethnic population is warranted.

FUNDING

Japanese Ministry of Health, Labour and Welfare.

B-type natriuretic peptide and amino-terminal pro-B-type natriuretic peptide in pediatric patients with pulmonary arterial hypertension

OBJECTIVES

B-type natriuretic peptide (BNP) and the amino-terminal fragment (NTproBNP) correlate with clinical variables, but have not been simultaneously studied in a large number of pediatric patients with pulmonary arterial hypertension (PAH). The purpose of our investigation was to compare BNP and NTproBNP with clinical indicators of disease in a pediatric PAH population for which biomarkers are much needed.

DESIGN

We retrospectively compared BNP and NTproBNP levels with exercise capacity, echocardiographic data, and hemodynamics in PAH patients under 21 years old. Two hundred sixty-three blood samples from 88 pediatric PAH patients were obtained, with BNP and NTproBNP drawn at the same time.

RESULTS

There was a correlation between BNP and NTproBNP with mean pulmonary arterial pressure/mean systemic arterial pressure ratio (r= 0.40, P < .01; r= 0.45, P < .01; respectively), mean right atrial pressure (r= 0.48, P < .01; r= 0.48, P < .01), and tricuspid regurgitant velocity (r= 0.36, P < .01; r= 0.41, P < .01). BNP and NTproBNP are associated with 6-minute walk distance, mean pulmonary arterial pressure, mean pulmonary arterial pressure/mean systemic arterial pressure ratio, mean right atrial pressure, pulmonary vascular resistance index, and tricuspid regurgitant velocity when investigated longitudinally. On the average, a 1-unit increase in log BNP or NTproBNP was associated with 4.5 units × m(2) or 3.4 units × m(2) increase in pulmonary vascular resistance index, respectively. There was a strong correlation between log BNP and log NTproBNP measurements (r= 0.87, P < .01).

CONCLUSION

In pediatric PAH, BNP and NTProBNP are strongly correlated and predict changes in clinical variables and hemodynamics. In a cross-sectional analysis, NTproBNP correlated with echocardiographic and exercise data better than BNP; NTproBNP showed less within patient variability over time; therefore, NTproBNP can add additional information toward predicting these clinical measurements.

Circulating myeloid-derived suppressor cells are increased and activated in pulmonary hypertension

BACKGROUND

Myeloid-derived suppressor cells (MDSCs) are increased in inflammatory and autoimmune disorders and orchestrate immune cell responses therein. Pulmonary hypertension (PH) is associated with inflammation, autoimmunity, and lung vascular remodeling. Immature myeloid cells are found in the lungs of humans and animals with PH, and we hypothesized that they would be increased in the blood of patients with PH compared with control subjects.

METHODS

Twenty-six children with PH and 10 undergoing cardiac catheterization for arrhythmia ablation were studied. Five milliliters of fresh blood were analyzed using flow cytometry. Results were confirmed using magnetic bead sorting and immunofluorescence, while quantitative polymerase chain reaction and intracellular urea concentration assays were used as measures of MDSC arginase-1 activation.

RESULTS

Flow cytometry demonstrated enrichment of circulating MDSCs among patients with PH (n = 26; mean, 0.271 × 10(6) cells/mL ± 0.17; 1.86% of CD45(+) population ± 1.51) compared with control subjects (n = 10; mean, 0.176 × 10(6) cells/mL ± 0.05; 0.57% of CD45(+) population ± 0.29; P < .05). Higher numbers of circulating MDSCs correlated to increasing mean pulmonary artery pressure (r = 0.510, P < .05). Among patients with PH, female patients had a twofold increase in MDSCs compared with male patients. Immunofluorescence analysis confirmed the results of flow cytometry. Quantitative reverse transcription polymerase chain reaction assay results for arginase-1 and measurement of intracellular urea concentration revealed increased activity of MDSCs from patients with PH compared with control subjects.

CONCLUSIONS

Circulating activated MDSCs are significantly increased in children with PH compared with control subjects. Further investigation of these cells is warranted, and we speculate that they might play significant immunomodulatory roles in the disease pathogenesis of PH.

Connective tissue disease presenting with signs and symptoms of pulmonary hypertension in children

Our case series describes three children who were initially diagnosed as having severe pulmonary arterial hypertension (PAH) and subsequently found to be positive for specific autoantibodies suggestive of an underlying autoimmune process. The signs and symptoms of PAH are subtle and may be part of the initial presentation of childhood connective tissue disease (CTD). Evaluation for connective tissue disease in the newly diagnosed pulmonary hypertension (PH) patient is important because early diagnosis of PH as well as CTD is crucial in the successful management of these complex patients. Ongoing monitoring for CTD in patients with severe PAH is warranted.

Circulating fibrocytes are increased in children and young adults with pulmonary hypertension

Chronic inflammation is an important component of the fibroproliferative changes that characterise pulmonary hypertensive vasculopathy. Fibrocytes contribute to tissue remodelling in settings of chronic inflammation, including animal models of pulmonary hypertension (PH). We sought to determine whether circulating fibrocytes were increased in children and young adults with PH. 26 individuals with PH and 10 with normal cardiac anatomy were studied. Fresh blood was analysed by flow cytometry for fibrocytes expressing CD45 and procollagen. Fibrocyte numbers were correlated to clinical and haemodynamic parameters, and circulating CC chemokine ligand (CCL)2 and CXC chemokine ligand (CXCL)12 levels. We found an enrichment of circulating fibrocytes among those with PH. No differences in fibrocytes were observed among those with idiopathic versus secondary PH. Higher fibrocytes correlated to increasing mean pulmonary artery pressure and age, but not to length or type of treatment. Immunofluorescence analysis confirmed flow sorting specificity. Differences in plasma levels of CCL2 or CXCL12, which could mobilise fibrocytes from the bone marrow, were not found. We conclude that circulating fibrocytes are significantly increased in individuals with PH compared with controls. We speculate that these cells might play important roles in vascular remodelling in children and young adults with pulmonary hypertension.

Common variants in CASP3 confer susceptibility to Kawasaki disease

Kawasaki disease (KD; OMIM 611775) is an acute vasculitis syndrome which predominantly affects small- and medium-sized arteries of infants and children. Epidemiological data suggest that host genetics underlie the disease pathogenesis. Here we report that multiple variants in the caspase-3 gene (CASP3) that are in linkage disequilibrium confer susceptibility to KD in both Japanese and US subjects of European ancestry. We found that a G to A substitution of one commonly associated SNP located in the 5' untranslated region of CASP3 (rs72689236; P = 4.2 x 10(-8) in the Japanese and P = 3.7 x 10(-3) in the European Americans) abolished binding of nuclear factor of activated T cells to the DNA sequence surrounding the SNP. Our findings suggest that altered CASP3 expression in immune effecter cells influences susceptibility to KD.

Autoimmune thyroid disease in children and adolescents with idiopathic pulmonary arterial hypertension

BACKGROUND

Previous studies have reported a high prevalence of autoimmune thyroid disease (AITD) in adult patients with pulmonary arterial hypertension (PAH). The aim of this retrospective study was to determine the prevalence of AITD in children and adolescents with idiopathic PAH (IPAH).

METHODS AND RESULTS

The study group included 16 patients who had been diagnosed as having idiopathic PAH when they were younger than 15 years old; all were younger than 20 years of age. Thyroid function and antithyroid antibody levels were examined regularly at 6-12-month intervals and when there were clinical signs of thyroid dysfunction. In total, 7 patients (44%) had AITD; 2 patients developed Graves' disease, 2 developed silent thyroiditis, and 3 had antithyroid antibodies with euthyroidism. The duration after PAH onset and the prostacyclin (PGI(2)) treatment period were significantly longer in patients with AITD (7.6+/-2.1 and 7.4+/-2.3 years, respectively) than in patients without AITD (5.0+/-1.1 and 4.8+/-1.2 years, respectively; P<0.01 and P<0.05).

CONCLUSIONS

The prevalence of AITD is high in children and adolescents with IPAH, so evaluation of thyroid function is important to prevent deterioration of right heart failure.

Abnormal Tissue Doppler Images are Associated With Elevated Plasma Brain Natriuretic Peptide and Increased Oxidative Stress in Acute Kawasaki Disease

BACKGROUND

The aims of this study were to evaluate myocardial mechanics using pulsed tissue Doppler imaging (TDI), and to determine the relationship between abnormal myocardial performance and plasma brain natriuretic peptide (BNP) levels and oxidative stress in acute Kawasaki disease (KD).

METHODS AND RESULTS

Consecutive TDI parameters, including peak systolic velocity (Sw) and early (Ew) and late diastolic excursion of the mitral annuli were obtained in 42 patients with KD (mean age: 2.4+/-0.4 years) in weeks 1, 2, and 3, and during convalescence. Plasma BNP level and urinary 8-isoprostane were also examined during the acute phase. These data were then compared with TDI profiles from 62 healthy children, plasma BNP levels in 38 controls with other febrile illnesses, and urinary 8-isoprostane levels in 13 healthy children. Ew in week 1 was significantly lower than in controls, subsequently normalizing in the convalescent stage. Plasma BNP level in acute KD patients was significantly higher (65+/-9 pg/ml) than in controls (13+/-2 pg/ml). Urinary 8-isoprostane level in acute KD patients was significantly higher as compared with control (596 +/-37 vs 379+/-26 pg/ml Cr, p<0.05). There was a significant negative correlation between week 1 Sw and plasma BNP level (r=-0.55, p=0.0001). Change in Sw velocity in the BNP >/=51 group was significantly greater than in the BNP <51 group. There was a significant negative correlation between week 1 Sw and urinary 8-isoprostane level (r=-0.48, p=0.001).

CONCLUSIONS

Latent abnormal tissue Doppler profiles, possibly reflecting long-axis systolic and diastolic dysfunction have been noted in KD patients. Abnormal myocardial mechanics may contribute to the increased plasma BNP level and enhanced oxidative stress may contribute to cardiac dysfunction in KD.