Congenital Cardiac Anomalies
Overview
The two topics of focus for the 2017 annual review of CARIS was congenital cardiac anomalies, and also anomalies associated with maternal type 1 and type 2 diabetes.
The system most commonly affected by a congenital anomaly is the cardiac system. The British Heart Foundation(2013)[1] suggested that 1 in 180 babies was born in the UK with congenital heart disease, but that the rate has been decreasing over the last 30 years. They also reported a higher rate of CCA in children born of multiple births than in children born of single births.
The cumulative prevalence in Wales between 1998 and 2021 was 122.1 cases of any circulatory anomaly per 10,000 births. There are now about 90 cases of severe congenital cardiac anomaly reported in Wales each year, and antenatal detection of the conditions is increasing with advances in screening.
Across Europe, EUROCAT collates data from registers across Europe, and this has suggested that prevalence of any congenital heart defect was 65 per 10,000 births (2011 to 2015).
Many of the congenital cardiac anomalies in babies born alive in Wales require complex surgical intervention very soon after birth. More information about congenital cardiac conditions is available from :
The Children’s Heart Federation is a UK parent led charity providing support for families with congenital cardiac conditions and their details may be found here :
This review concentrates on six serious anomalies seen in Wales:
- Coarctation of the aort
- Transportation of the great arteries
- Fallot's tetralogy
- Hypoplastic left heart syndrome
- Double outlet right ventricle
- Truncus arteriosus
The most commonly occurring anomaly seen in Wales (but not discussed further here) is Ventricular Septal Defect (VSD) with 3,152 cases registered on CARIS to date. 50 cases per 10,000 births were detected between 1998 and 2016. VSD may also be present in some of the anomalies above. Other anomalies that are seen include aortic valve stenosis, patent ductus arteriosus (PDA) and Ebstein’s anomaly.
The human cardiovascular system develops very early during gestation. By about the 22nd day of pregnancy, the structure that will become the heart begins to pump blood, and the rest of the system develops and matures throughout the pregnancy, and shortly after birth with the closure of the ductus arteriosus. As knowledge of genetics increases, so too does knowledge about how the cardiovascular system develops, and the importance of genetics in the process.
Early detection of a congenital cardiac anomaly allows for a planned delivery and neonatal management in a specialist centre, aimed at producing better outcomes for the baby. All pregnant women in Wales are offered an ultrasound scan at 18 to 20 weeks gestation in order to detect fetal anomalies including cardiac anomalies. The potential for detection was previously low but advances in ultrasound over recent years have improved antenatal detection rates of many conditions, so that between 2014 and 2016 100% of cases of hypoplastic left heart syndrome and nearly ¾ of cases of Fallot’s tetralogy were detected at this scan.
Coarctation of the Aorta
What is it?
Coarctation involves a narrowing of the aorta, which is the main artery in the human body. The defect can occur anywhere along the aorta but is commonly situated just after the subclavian artery at the level of the ductus arteriosus. The head and arms have a normal blood supply but the blood supply to the lower half of the body will be compromised.
Presentation later in childhood or as an adult usually suggests a less severe anomaly. Common later findings include high blood pressure in the arm, a discrepancy between the pulse and blood pressure in the upper and lower limbs, shortness of breath, headache, muscle weakness or cramps and nosebleeds. The cause of coarctation is not understood. It occurs twice as often in males and is often associated with other heart defects including a bicuspid aortic valve, valve stenosis, septal defects and a patent ductus arteriosus. It is also associated with some chromosomal abnormalities, most commonly Turner’s syndrome in girls, and 22q11 deletion.
How is it detected?
It can be detected at the anomaly scan that pregnant women are offered at 18 to 20 weeks gestation, but is quite difficult to see at this stage of development. Antenatal ultrasound features include a smaller left ventricle compared with the right and a smaller aorta and aortic arch. However less than a fifth of known cases (17.8%) of this condition in Wales are detected at this scan, and most are detected through echocardiograms, scans or x-rays after the birth has happened when it becomes apparent that the baby has a cardiac condition.
What are the effects on the fetus/baby?
Evidence of coarctation depends on the severity of narrowing. Severe coarctation of the aorta usually gives rise to clinical signs shortly after birth including pale skin, irritability, heavy sweating and difficulty breathing. At birth the closure of the ductus arteriosus results in abrupt obstruction to flow in the aorta and the baby can present with severe respiratory distress. However there is medication available which will ensure the ductus arteriosus remains open until surgery. If left untreated, severe coarctation may lead to heart failure and death.
How common is it in Wales?
360 cases of coarctation were recorded on the CARIS database between 1998 and 2016. This gives a rate in Wales of 5.7 per 10,000 births. Of these 93.1% were live-born, and 90% of babies survived to at least the age of one. EUROCAT which collates data from registers across Europe suggested that prevalence was 3.45 per 10,000 births (2011 to 2015). The Center for Disease Control and Prevention (CDC) in the USA estimates that about 4 per 10,000 babies are born in the USA with coarctation.
More information
http://www.nhsdirect.wales.nhs.uk/encyclopaedia/c/article/congenitalheartdisease/#1
https://www.cdc.gov/ncbddd/heartdefects/coarctationofaorta.html
Transposition of the Great Arteries
What is it?
Transposition of the great arteries is the most common cause of cyanotic heart disease in newborn infants and it is more common in males, with between 60% and 70% of cases occurring in males. The aorta and pulmonary arteries are ‘transposed’ with the aorta arising from the right ventricle and the pulmonary artery from the left ventricle, causing two separate circulations of blood. A connection between the two circulations is needed for oxygenated blood to reach the body tissues. This may occur through a ventricular septal defect (25% of cases) or continuation of the patent ductus arteriosus.
The cause of the condition is not known, and is probably multifactorial, but is thought to be more common in infants of diabetic mothers.
How is it detected?
It can be detected at the anomaly scan that pregnant women are offered at 18 to 20 weeks, and between 2014 and 2016, the detection rate was 53.1% in Wales.
What are the effects on the fetus/baby?
When the baby is born they usually present with cyanosis in the newborn period because of the lack of oxygenated blood circulating. Without surgery, over half of affected babies die before the age of two. With surgery, outlook has improved and, in the absence of other complications, survival is good, although lifelong follow up is required. A balloon septoplasty may be required shortly after birth to create an artificial septal defect until further surgery can be performed. Major correction of the defect involves an arterial switch operation in which the major arteries are reconnected to the correct ventricle.
How common is it in Wales?
There were 237 cases registered in Wales between 1998 and 2016, giving a rate of 3.7 cases per 10,000 births, nearly 79% of which were live born. EUROCAT which collates data from registers across Europe suggested that prevalence was 3.2 per 10,000 births (2011 to 2015).
CDC estimates that about 1 in every 3,300 babies (or 3 per 10,000) born in the USA are affected by this anomaly.
More information
http://www.nhsdirect.wales.nhs.uk/encyclopaedia/c/article/congenitalheartdisease/#transposition
https://www.cdc.gov/ncbddd/heartdefects/d-tga.html
Fallot's Tetralogy
What is it?
Fallot’s tetralogy is a form of cyanotic congenital heart disease which involves four significant heart defects:
- Anterior deviation (over-riding) of the aorta;
- Ventricular septal defect (VSD
- Pulmonary stenosis; and
- Right ventricular hypertrophy
Pulmonary stenosis limits blood flow to the lungs, causing a build-up of oxygen depleted blood on the right side of the heart. Right ventricular pressure rises to shunt the deoxygenated blood through the VSD and the over-riding aorta to the left side of the heart, without it passing through the lungs. Right ventricular hypertrophy develops as the right ventricle works to push an increased volume of blood through the stenotic pulmonary valve. The cause of the condition is unknown.
How is it detected?
It can be detected at the anomaly scan that pregnant women are offered at 18 to 20 weeks, and between 2014 and 2016, 27 out of 37 cases in Wales were detected (73%) at this scan. Once suspected, a confirmed diagnosis can be made through echocardiography and other scans. Cardiac catheterisation may also be required to study the pulmonary blood flow following delivery.
What are the effects on the fetus/baby?
At birth, cyanosis is rare as babies usually have a patent ductus arteriosus that improves pulmonary blood flow. As the ductus closes, cyanosis and a loud harsh murmur develop. Once diagnosed, initial management focuses on maintaining adequate blood oxygenation. Surgical correction is usually undertaken at about six months of age although earlier intervention may be required if oxygen levels are low. Survival rates for children with Fallot’s tetralogy have improved dramatically in recent decades. Babies with the condition are at a higher risk of developing endocarditis.
Fallot’s tetralogy may also be associated with other anomalies including omphalocoele, diaphragmatic hernia and chromosomal defects. There is a high incidence of chromosomal disorders in children with Fallot’s tetralogy, such as Down syndrome and DiGeorge syndrome (a condition that causes heart defects, low calcium levels and immune deficiency).
Picture credit: OpenStax, Anatomy & Physiology. OpenStax CNX. 30 Jul 2014 http://cnx.org/contents/14fb4ad7-39a1-4eee-ab6e-3ef2482e3e22@6.27.
How common is it in Wales?
232 cases were recorded on the CARIS database between 1998 to 2016, giving a rate of 3.6 per 10,000 births, of which 94% were live-born. EUROCAT which collates data from registers across Europe suggested that prevalence was 2.8 per 10,000 births (2011 to 2015). CDC suggests that 1 in every 2,518 (3.9 per 10,000) babies born in the USA are born with this condition.
More information
http://www.nhsdirect.wales.nhs.uk/encyclopaedia/c/article/congenitalheartdisease/#Tetra
Hypoplastic Left heart (HLH)
What is it?
Hypoplastic left heart syndrome is a congenital anomaly that affects blood flow through the heart, as the left side of the heart fails to develop during gestation. The condition affects the left ventricles, mitral valves, aortic valve and the aorta, all of which fail to develop as they should. They may not be fully formed or may be very small. Some babies with the condition also have an atrial septal defect present. There are two openings between the left and right side of the heart in a developing fetus – the ductus arteriosus and the foramen ovale. These usually remain open until a few days after birth, and continue to allow oxygenated blood to circulate as the system bypasses the left side of the heart which is underdeveloped.
How is it detected?
It can be detected at the anomaly scan that pregnant women are offered at 18 to 20 weeks, and between 2014 and 2016, 18 out of 18 cases were detected (100%). If it is not detected during the pregnancy then it can be diagnosed through the use of echocardiography and scans once the baby has been born.
What are the effects on the fetus/baby?
If not detected antenatally, the anomaly may not become apparent during the first few days of life, as oxygenated blood continues to circulate because the ductus arteriosus and foramen ovale remain open. However the condition very quickly becomes obvious once these two structures close and oxygenated blood can no longer circulate fully. Babies can become very breathless, and develop cyanosis (have a blue tinge to their skin) because of poor oxygen saturation. Their pulse becomes rapid and a heart murmur may be obvious to any clinician listening to the baby’s heart. If left untreated, they will fail to thrive. The surgery that is performed is to restore heart function is not a ‘cure’. They will need several operations done in stages to support the heart function and will need to be followed up medically throughout their lives.
How common is it in Wales?
There were 195 cases registered in Wales between 1998 and 2016, giving a rate of 3.1 cases per 10,000 births, of which 45% were live-born. EUROCAT which collates data from registers across Europe suggested that prevalence was 2.4 per 10,000 births (2011 to 2015). In the USA, CDC estimates that about 1 in every 4,344 babies born is born with HLHS (or 2.3 per 10,000 births).
More information
https://www.nhsdirect.wales.nhs.uk/encyclopaedia/c/article/congenitalheartdisease/#Ventricle
https://www.cdc.gov/ncbddd/heartdefects/hlhs.html
Double Outlet Right Ventricle (DORV)
What is it?
Double outlet right ventricle is a congenital anomaly in which the pulmonary artery and aorta are both connected to the right ventricle, instead of the aorta being connected to the left ventricle of the heart. A ventricular septal defect is also always present, and there may be other cardiac anomalies present too, including transposition of the great arteries; pulmonary valve stenosis; Fallot’s tetralogy; coarctation of the aorta; and mitral valve problems. The anomaly may vary in type and severity and because of the overlap with a range of other cardiac conditions, DORV is not always well documented. There is no identifiable genetic cause.
How is it detected?
It can be detected at the anomaly scan that pregnant women are offered at 18 to 20 weeks, and between 2014 and 2016, the detection rate was 61.5%. If it is not detected during the antenatal period, a diagnosis can be made soon after birth using chest x-rays and echocardiogram.
What are the effects on the fetus/baby?
As well as the frequent association with other cardiac anomalies, there are a number of different presentations of DORV so the condition of the baby varies according to the type of DORV present and the accompanying conditions. Babies with DORV will develop symptoms that may include failure to thrive, sweating, breathlessness, cyanosis or blueness of the skin and swelling of the legs and abdomen. The baby will need surgery but again this will depend on the type and severity of DORV and the other conditions present.
How common is it in Wales?
134 cases were registered in Wales between 1998 and 2016, giving a rate of 2.1 per 10,000 births, of which 77% were live-born. EUROCAT which collates data from registers across Europe suggested that prevalence was 1.3 per 10,000 births (2011 to 2015).
More information
https://www.orpha.net/data/patho/Pro/en/DoubleOutletRightVentricle-FRenPro3450.pdf
Truncus Arteriosus
What is it?
Instead of separate pulmonary arteries and aorta, in this anomaly a single large arterial trunk arises from the two heart ventricles. The anomaly is often associated with a large ventricular septal defect which allows oxygenated and deoxygenated blood to mix in what is effectively a single ventricle. As a result, the flow of blood to the lungs is increased, causing pulmonary congestion and potentially life threatening pulmonary hypertension. A number of types of the defect have been identified, depending on the anatomy of the trunk. Truncus arteriosus is linked with various other anomalies including chromosomal defects, DiGeorge syndrome, renal agenesis and pulmonary hypoplasia.
How is it detected?
It can be detected at the anomaly scan that pregnant women are offered at 18 to 20 weeks, and between 2012 and 2016 the detection rate was 44.4%. Antenatal ultrasound detection has previously been difficult as the four chamber view of the heart may be normal. However detection has improved in recent years with advances in antenatal ultrasound imaging of the outflow tracts. If it is not detected antenatally but diagnosed in the neonatal period, then diagnosis is made using an echocardiogram and other scans.
What are the effects on the fetus?
Postnatally, symptoms usually appear within the first few days of life, with breathlessness and signs of heart failure. Complete surgical repair is needed to close the septal defect and to separate the pulmonary arteries from the arterial trunk. This usually provides good results although further surgery may be required as the child grows. Heart failure and pulmonary hypertension are recognised complications. If untreated, death usually occurs during infancy.
How common is it in Wales?
66 cases were recorded on the CARIS database between 1998 and 2016, giving a rate of 1 per 10,000 births. 64% were born alive. This is the least common of the cardiac conditions discussed here. CDC estimates that there is less than one case per 10,000 live births in the USA, and EUROCAT which collates data from registers across Europe suggested that prevalence was 0.51 per 10,000 births (2011 to 2015).
More information
http://www.nhsdirect.wales.nhs.uk/encyclopaedia/c/article/congenitalheartdisease/#Truncus
https://www.cdc.gov/ncbddd/heartdefects/truncusarteriosus.html
[1]Townsend N, Bhatnagar P, Wickramasinghe K, Williams J, Vujcich D, Rayner M (2013). Children and young people statistics 2013. British Heart Foundation: London.