Down syndrome and associated atrioventricular septal defects in a nationwide Norwegian cohort: Prevalence, time trends, and outcomes

INTRODUCTION

The prevalence of Down syndrome (DS) is approximately 1 per 1000 births and is influenced by increasing maternal age over the last few decades. DS is strongly associated with congenital heart defects (CHDs), especially atrioventricular septal defect (AVSD). Our objectives were to investigate the prevalence of live-born infants with DS having a severe CHD in the Norwegian population over the last 20 years and compare outcomes in infants with AVSD with and without DS.

MATERIAL AND METHODS

Information on all births from January 1, 2000 to December 31, 2019 was obtained from the Medical Birth Registry of Norway. We also obtained data on all infants with severe CHDs in Norway registered in Oslo University Hospital's Clinical Registry for Congenital Heart Defects during 2000-2019 and accessed individual-level patient data from the electronic hospital records of selected cases. Infants with AVSD and DS were compared to infants with AVSD without chromosomal defects. Crude and adjusted odds ratios (ORs) of infant mortality and need for surgery during the first year of life, with associated 95% confidence intervals (CIs), were estimated by logistic regression.

RESULTS

A total of 1 177 926 infants were live-born in Norway during the study period. Among these, 1456 (0.1%) had DS. The prevalence of infants with DS having a severe CHDs was relatively stable, with a mean of 17 cases per year. The most common CHD associated with DS was AVSD (44.4%). Infants with AVSD and DS were more likely to have cardiac intervention during their first year of life compared to infants with AVSD without chromosomal defects (adjusted OR [aOR]: 2.52; 95% CI 1.27, 4.98). However, we observed no difference in infant mortality during first year of life between the two groups (aOR: 1.08; 95% CI 0.43, 2.70).

CONCLUSIONS

The prevalence of live-born infants with severe CHDs and DS has been stable in Norway across 20 years. Infants with AVSD and DS did not have higher risk of mortality during their first year of life compared to infants with AVSD without chromosomal defects, despite a higher risk of operative intervention.

Development of pulmonary hypertension remains a major hurdle to corrective surgery in Down syndrome

Down syndrome is the most common chromosomal abnormality encountered in clinical practice with 50% of them having associated congenital heart disease (CHD). Shunt lesions account for around 75% of all CHDs in Down syndrome. Down syndrome patients, especially with large shunts are particularly predisposed to early development of severe pulmonary hypertension (PH) compared with shunt lesions in general population. This necessitates timely surgical correction which remains the only viable option to prevent long term morbidity and mortality. However, despite clear recommendations, there is wide gap between actual practice and fear of underlying PH which often leads to surgical refusals in Down syndrome even when the shunt is reversible. Another peculiarity is that Down syndrome patients can develop PH even after successful correction of shunt. It is not uncommon to come across Down syndrome patients with uncorrected shunts in adulthood with irreversible PH at which stage intracardiac repair is contraindicated and the only option available is a combined heart-lung transplant. However, despite the guidelines laid by authorities, the rates of cardiac transplant in adult Down syndrome remain dismal largely attributable to the high prevalence of intellectual disability in them. The index case presents a real-world scenario highlighting the impact of severe PH on treatment strategies and discrimination driven by the fear of worse outcomes in these patients.

Cardiovascular Complications of Down Syndrome: Scoping Review and Expert Consensus

Cardiovascular disease is a leading cause of morbidity and mortality in individuals with Down syndrome. Congenital heart disease is the most common cardiovascular condition in this group, present in up to 50% of people with Down syndrome and contributing to poor outcomes. Additional factors contributing to cardiovascular outcomes include pulmonary hypertension; coexistent pulmonary, endocrine, and metabolic diseases; and risk factors for atherosclerotic disease. Moreover, disparities in the cardiovascular care of people with Down syndrome compared with the general population, which vary across different geographies and health care systems, further contribute to cardiovascular mortality; this issue is often overlooked by the wider medical community. This review focuses on the diagnosis, prevalence, and management of cardiovascular disease encountered in people with Down syndrome and summarizes available evidence in 10 key areas relating to Down syndrome and cardiac disease, from prenatal diagnosis to disparities in care in areas of differing resource availability. All specialists and nonspecialist clinicians providing care for people with Down syndrome should be aware of best clinical practice in all aspects of care of this distinct population.

Predictors of major adverse events and complications after ventricular septal defects surgical closure in children less than 10 kg

Background

Ventricular septal defect (VSD) is the most common congenital cardiac defect for which outcomes are not uniform. There is a lack of consensus on the risk factors for the unfavorable outcomes following surgical VSD closure.

Aim

The aim of this study was to determine the risk factors and the predictors of major adverse events (MAEs) and complications following surgical closure of VSD in children weighing less than 10 kg.

Methods

This retrospective cohort study included children less than 10 kg who underwent surgical closure of congenital VSD of any type with or without associated congenital heart diseases. Patients with associated major cardiac anomalies were excluded. Preoperative, operative and postoperative data were collected from medical records.

Results

This study included 127 patients 52.8% were males, the median age was 8.0 months (IQR = 6.0–11.0 months), and their median weight was 5.7 kg (IQR = 4.8–7.0). Mortality was in one patient (0.8%) Multivariable logistic regression analysis revealed that male sex group (observational data), previous pulmonary artery banding (PAB), and significant intraoperative residual VSD were significant risk factors for the development of MAEs (odds ratios were 3.398, 14.282, and 8.634, respectively). Trisomy 21 syndrome (odds ratio: 5.678) contributed significantly to prolonged ventilation. Pulmonary artery banding (odds ratio: 14.415), significant intraoperative (3 mm) residual VSD (odds ratio: 11.262), and long cross-clamp time (odds ratio: 1.064) were significant predictors of prolonged ICU stay, whereas prolonged hospital stay was observed significantly in male sex group (odds ratio: 12.8281), PAB (odds ratio: 2.669), and significant intraoperative (3 mm) residual VSD (odds ratio: 19.551).

Conclusions

Surgical VSD repair is considered a safe procedure with very low mortality. Trisomy 21 was a significant risk factor for prolonged ventilation. Further, PAB, significant intraoperative residual of 3 mm or more that required a second pulmonary bypass, and a greater cross-clamp time were significant predictors of MAE and associated complications with prolonged ICU and hospital stay.

The evolving treatment of congenital heart disease in patient with Down syndrome: Current state of knowledge

OBJECTIVES

Children with Down syndrome are usually seen as not worthy of high-risk cardiac surgery. Through this review, we try to show the results of curative and palliative surgery for functional single ventricle syndrome in patients with Down syndrome, as there is currently no standard protocol for the treatment of this category of patients.

METHODS

An exhaustive search of all related published medical literature included the following domains: Down syndrome and diagnosis, Down syndrome and taxonomy, Down syndrome, and natural history, Down syndrome and cardiovascular abnormalities, Down syndrome and pulmonary hypertension, Down syndrome and institutionalization, Down syndrome and surgical repair, Down syndrome, and single ventricle palliation, Down syndrome and Glenn, Down syndrome, and Fontan.

RESULTS

12 articles were included from 775 identified. Low-risk cardiac surgery procedure should be provided for Down syndrome with a balanced ventricular septal defect. There is no universal agreement about the surgical approach for Down syndrome with unbalanced ventricular septal defects, but it can be performed at relatively low risk.

CONCLUSIONS

TCPC in Down syndrome patients could be a relatively low-risk procedure if patients are prepared well and their pulmonary vascular resistance is low. Randomized prospective studies are required to show the long-term impact of TCPC palliation and develop a better understanding of standardized care of these patients.

Hemodynamic Characteristics After Fontan Procedure in Patients with Down's Syndrome

Patients with Down's syndrome (DS) are generally regarded as not being good candidates for the Fontan procedure. However, detailed hemodynamic changes over time are not fully clarified. A retrospective chart review of all patients with DS who underwent the Fontan procedure and 5 times that number of Fontan patients without DS performed in Fukuoka Children's Hospital and Kyushu University Hospital. Seven Fontan patients with DS were identified, and 35 Fontan patients without DS were recruited. During the mean observational periods of 14.7 years and 15.0 years (DS and non-DS, respectively) after the Fontan procedure, only one DS patient died. Central venous pressure (CVP) and transpulmonary pressure gradient significantly increased, and arterial oxygen saturation significantly decreased over time in DS patients after the Fontan procedure compared with those without DS. CVP in DS patients after the Fontan procedure increased over time compared with non-DS patients. Better management including the efficacy of Pulmonary arterial hypertension-specific therapy should be clarified in further studies.

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.

Long-Term Survival and Causes of Death in Children with Trisomy 21 After Congenital Heart Surgery

OBJECTIVE

To evaluate long-term transplant-free survival and causes of death in the trisomy 21 (T21) population after surgery for congenital heart disease (CHD) in comparison with patients who are euploidic.

STUDY DESIGN

This is a retrospective cohort study from the Pediatric Cardiac Care Consortium, enriched with prospectively collected data from the National Death Index and the Organ Procurement and Transplantation Network for patients with sufficient direct identifiers. Kaplan-Meier survival plots were generated and multivariable Cox proportional hazards models were used to examine risk factors for mortality between patients with T21 and 1:1 matched patients with comparable CHD who are euploidic.

RESULTS

A long-term survival analysis was completed for 3376 patients with T21 (75 155 person-years) who met inclusion criteria. The 30-year survival rate for patients with T21 ranged from 92.1% for ventricular septal defect to 65.3% for complex common atrioventricular canal. Of these, 2185 patients with T21 were successfully matched with a patient who was euploidic. After a median follow-up of 22.86 years (IQR, 19.45-27.14 years), 213 deaths occurred in the T21 group (9.7%) compared with 123 (5.6%) in the euploidic comparators. After adjustment for age, sex, era, CHD complexity, and initial palliation, the hazard ratio of CHD-related mortality was 1.34 times higher in patients with T21 (95% CI, 0.92-1.97; P = .127).

CONCLUSIONS

CHD-related mortality for patients with T21 after cardiac surgical intervention is comparable with euploidic comparators. Children with T21 require lifelong surveillance for co-occurring conditions associated with their chromosomal abnormality.

Mortality Among Children with Down syndrome in Hong Kong: A Population-Based Cohort Study from Birth

OBJECTIVES

To describe the mortality patterns, comorbidities, and attendance at accident and emergency departments among children with Down syndrome in Hong Kong.

STUDY DESIGN

This is a population-based, retrospective cohort study of live births of children with Down syndrome delivered between 1995 and 2014, as identified from territory-wide hospitalization data in Hong Kong. The Kaplan-Meier product limit method was adopted to estimate the survival probabilities of children with Down syndrome by selected demographic and clinical characteristics. Cox regression analyses were conducted to examine associations of comorbidities and accident and emergency department accident and emergency departments attendances with mortality patterns.

RESULTS

There were 1010 live births of children with Down syndrome in Hong Kong within the study period and the average rate of live births with Down syndrome was 8.0 per 10 000 live births (95% CI, 6.8-9.30). The rate of live births with Down syndrome over the past 2 decades decreased from 11.8 per 10 000 live births in 1995 to 3.4 per 10 000 in 2014. Eighty-three patients with Down syndrome died during this period. The overall 6-month and 1- and 5-year survival probabilities were 95.8%, 94.4%, and 92.6%, respectively. There was a significant decrease in mortality rates over the study period, particularly among those born between 2000-2004 and 2005-2009 compared with those born between 1995 and 1999 (P < .05). Patients with Down syndrome without congenital cardiovascular anomalies and without low birth weight had lower mortality rates than those with these diagnoses.

CONCLUSIONS

Over the past 2 decades, the early life mortality of children with Down syndrome in Hong Kong has improved significantly along with a reduction in Down syndrome live births.

Effect of Trisomy 21 on Postoperative Length of Stay and Non-cardiac Surgery After Complete Repair of Tetralogy of Fallot

Trisomy 21 (T21) is the most common chromosomal abnormality, and is frequently associated with congenital heart disease. Results of previous studies evaluating the effect of T21 on postoperative outcomes and complications following heart surgery have been mixed. Our goal was to determine if T21 is associated with higher frequency of adverse postoperative outcomes following repair of tetralogy of Fallot (TOF). A query of the Pediatric Health Information System was performed for patients who underwent complete repair of TOF from 2004 to 2015. Patients with a genetic syndrome other than T21 and tracheostomy and/or gastrostomy prior to heart surgery were excluded. Two groups were created on the basis of whether patients received a diagnostic code for T21. The adverse outcomes of interest were postoperative mortality, postoperative length of stay (LOS), postoperative gastrostomy, and postoperative tracheostomy. Univariate and Kaplan-Meier analysis were performed to evaluate outcomes. There were a total of 4790 patients; 430 (9%) patients had T21, and 4360 (91%) patients without a genetic diagnosis. There was no significant difference in mortality before discharge between those with and without T21 (2.3% vs 1.4%; p = 0.155). Patients with T21 had longer postoperative LOS (mean of 19.8 days vs 12.4 days; p < 0.001), and higher rates of postoperative gastrostomy (13.3% vs 5.3%; p < 0.02). There was no significant difference between groups for rates of postoperative tracheostomy (1.9% vs 1.2%; p = 0.276). Kaplan-Meier analysis confirmed that patients with T21 had longer postoperative LOS and greater incidence of gastrostomy.

Ten-year trend in prevalence and outcome of Down syndrome with congenital heart disease in a middle-income country

Limited data are available on the survival of patients with Down syndrome and congenital heart disease (CHD) from middle-income countries. This retrospective cohort study was performed to determine the trends in the prevalence and survival of such patients born from January 2006 to December 2015 in Malaysia. Among 754 patients with Down syndrome, 414 (55%) had CHD, and no significant trend was observed during the 10 years. Of these 414 patients, 30% had lesions that closed spontaneously, 35% underwent surgery/intervention, 9% died before surgery/intervention, and 10% were treated with comfort care. The overall mortality rate was 23%, the median age at death was 7.6 months, and no significant changes occurred over time. The early and late post-surgery/intervention mortality rates were 0.7% and 9.0%, respectively. Most deaths were of non-cardiac causes. The overall 1-, 5-, and 10-year survival rates were 85.5%, 74.6%, and 72.9%, respectively. Patients with severe lesions, persistent pulmonary hypertension of the newborn, atrioventricular septal defect, and pulmonary hypertension had low survival at 1 year of age.Conclusion: The prevalence of CHD in patients with Down syndrome is similar between Malaysia and high-income countries. The lower survival rate is attributed to limited expertise and resources which limit timely surgery. What is Known: • The survival of patients with Down syndrome with congenital heart disease (CHD) has improved in high-income countries. However, little is known about the survival of patients with Down syndrome with CHD from middle-income countries. • In the Caucasian population, atrioventricular septal defect is the most common type of CHD associated with Down syndrome. What is New: • In middle-income countries, the prevalence of CHD is the same as in high-income countries, but with a lower survival rate. • In the Asian population, ventricular septal defect is the most common type of CHD in patients with Down syndrome.

Relationship Between Pulmonary Arterial Resistance and Compliance in Patients with Down Syndrome

This study aimed to clarify the characteristics of pulmonary arterial resistance (Rp)-compliance (Cp) coupling in individuals with Down syndrome (DS), who have increased risks of pulmonary arterial hypertension (PAH). We performed cardiac catheterization before and after corrective surgery in 85 DS infants and 85 controls with congenital heart disease and PAH. We retrospectively collected hemodynamic data and compared Rp and Cp between the groups. Age at surgery was 3.5 (2.6-4.6) months. The first and second catheterizations were performed 1 month before and after corrective surgery in both groups. Preoperative Cp in DS patients was significantly lower than that in controls [2.27 (1.62-3.0) vs. 2.50 (1.86-3.31) mL/mmHg/m², p = 0.039], although there was no significant difference in mean pulmonary arterial pressure and Rp between the groups. Analysis of covariance revealed that the slopes of the preoperative regression lines for the logarithmic transformations of Rp and Cp were identical in DS patients and controls (p = 0.299). However, the postoperative regression line was shifted downward in DS patients after corrective surgery. Postoperative home oxygen therapy (HOT) was performed in 39 patients (36 DS patients) and multivariate logistic regression analysis revealed that postoperative HOT was significantly related to low preoperative Cp (p = 0.039) and DS (p = 0.0001). Individuals with DS have the unique pulmonary vasculature characterized with low Cp that is related to postoperative HOT.

Cardiovascular disease in Down syndrome

PURPOSE OF REVIEW

In the last 40 years, with a better understanding of cardiac defects, and with the improved results of cardiac surgery, the life expectancy of persons with Down syndrome has significantly increased. This review article reports on advances in knowledge of cardiac defects and cardiovascular system of persons with trisomy 21.

RECENT FINDINGS

New insights into the genetics of this syndrome have improved our understanding of the pathogenetic mechanisms of cardiac defects. Recent changes in neonatal prevalence of Down syndrome suggest a growing number of children with cardiac malformations, in particular with simple types of defects. Ethnic and sex differences of the prevalence of specific types of congenital heart disease (CHD) have also been underlined. A recent study confirmed that subclinical morphologic anomalies are present in children with trisomy 21, also in the absence of cardiac defects, representing an internal stigma of Down syndrome. The results of cardiac surgery are significantly improved in terms of immediate and long-term outcomes, but specific treatments are indicated in relation to pulmonary hypertension. Particular aspects of the cardiovascular system have been described, clarifying a reduced sympathetic response to stress but also a 'protection' from atherosclerosis and arterial hypertension in these patients.

SUMMARY

Continuing dedication to clinical and basic research studies is essential to further improve survival and the quality of life from childhood to adulthood of patients with trisomy 21.