Pulmonary atresia with ventricular septal defect | |
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Other names | PA-VSDS (abbr.) [1] |
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Pulmonary atresia with ventricular septal defect | |
Specialty | Medical genetics |
Risk factors | Genetic and environmental factors usually come into place |
Diagnostic method | Radiological studies such as chest CT scans. |
Differential diagnosis | Pulmonary atresia |
Prognosis | poor without treatment |
Frequency | rare |
Deaths | untreated PAVSD patients more likely to suffer from a premature death |
Pulmonary atresia with ventricular septal defect is a rare birth defect characterized by pulmonary valve atresia occurring alongside a defect on the right ventricular outflow tract. [2] [3] [4] [5]
It is a type of congenital heart disease/defect, [6] and one of the two recognized subtypes of pulmonary atresia, the other being pulmonary atresia with intact ventricular septum. [7] [8]
The condition consists of atresia affecting the pulmonary valve and a hypoplastic right ventricular outflow tract. The ventricular septal defect doesn't impede the in and outflowing of blood in the ventricular septum, which helps it form during fetal life. [3] [5]
The spectrum of symptoms exhibited by children with this condition depends on the severity of the condition, while some barely show symptoms, others might develop complications such as congestive heart failure. [9] [10] [11]
In symptomatic children, symptoms become apparent soon after birth, these usually consist of the following: [3] [5] [10] [12] [13] [14] [15]
Other features can occur alongside this birth defect, including other congenital anomalies such as polydactyly, microcephaly, congenital hearing loss (sensorineural type), renal agenesis, dextrocardia, etc. [16] [17]
The condition has been called a severe form of Tetralogy of Fallot. [18] [19] [9] [20] [21] [12] [11]
If deformed blood vessels coming from the thoracic aorta appear alongside this condition, the phenotype is renamed to pulmonary atresia with ventricular septal defect and major aortopulmonary collaterals. [22]
Children with this condition are at a higher risk of developing the following complications: [11] [23]
Children whose PAVSD is caused by DiGeorge syndrome (also known as 22q11.2 deletion syndrome) are more likely to suffer from the post-surgical complications (especially respiratory ones) associated with surgeries that treat this defect. [24]
Women with PAVSD are at a slightly higher risk of being infertile and having miscarriages or children with a congenital heart defect. [25]
Airway hyperresponsiveness is a commonly seen co-morbidity among those afflicted with PAVSD. [26]
Pulmonary atresia in PAVSD takes place during the first 8 weeks of fetal life, when the pulmonary valve that is supposed to form, fails to form, this doesn't allow blood to flow through the pulmonary artery from the right ventricle. The ventricular septal defect associated with PAVSD lets the right ventricule form. [27] [28] [29] [30]
In some cases of PAVSD, major aortopulmonary collateral arteries develop; in a normal fetus, these arteries usually develop but then start deteriorating after pulmonary arteries grow, in fetuses with PAVSD, the pulmonary arteries don't develop, and this gives a chance to the major aortopulmonary collateral arteries to develop fully. [31]
The mildest variant of pulmonary atresia with ventricular septal defect involves pulmonary atresia with normally developed main pulmonary artery and branch pulmonary arteries, the blood that flows to the lungs from the right side of the heart goes to the left side of the heart through the ventricular septum which then flows through the patent ductus arteriosus. The most severe variant involves the presence of severely hypoplastic main pulmonary arteries and branch pulmonary arteries, alongside agenesis of the patent ductus arteriosus. Blood flow to the lungs comes from various dysplastic (malformed) blood vessels from the thoracic aorta called major aortapulmonary collateral arteries, these blood vessels narrow down as time goes on. [32] [33] [34]
Although this birth defect is congenital, the exact cause is unknown, and it may vary between children with the condition, the following factors have been known to influence the risk of a baby being born with the condition: [35] [36]
The molecular genetics of this condition isn't known in most people with PA(VSD), however, there have been candidate genes found to be possibly implicated in the pathogenesis of this condition: [37] [38]
There have also been copy number variants described in the medical literature as associated with PA(VSD): [39]
A 1998 study done in Britain revealed that children with a mother who had a congenital heart defect (including PAVSD) had a higher risk of being born with a congenital heart defect themselves than those whose father had a congenital heart defect. [40]
Some cases of PA(VSD) have been associated with genetic syndromes such as VACTERL association, Alagille syndrome, CHARGE syndrome, trisomy 13, 18, and 21. [32] [2] [41]
While congenital heart defects can't be acquired, they can also be caused by environmental factors the mother exposed herself to before and/or during pregnancy, these include: [42]
Maternal exposure to carbon monoxide from smoke (e.g. from cigarettes) has been known for having the ability of quickly crossing the placenta into the fetus, which then attaches itself to fetal haemoglobin, leaving a shortage of nutrients and oxygen as a result. A relation between these events and congenital heart disease (including PAVSD) has been showed in 3 recent meta-analyses. [42]
Paternal smoking (that is, smoking by the father) has also been shown to be a contributing factor to congenital heart disease; while light smoking slightly increased the risk of the man's offspring having a (congenital) conotruncal heart defect, heavy smoking of more than 14 cigarettes a day doubled the risk for said man to have a child with congenital heart disease. Higher amounts than this were linked to a higher risk of having children with septal defects and/or obstruction of the left ventricular outflow tract. [42]
Other risk factors include maternal obesity, diabetes, rubella, indomethacin tocolysis, phenylketonuria, or elderly age. [43] [9]
A link between certain genes and maternal smoking has been shown to increase the chance of having children with congenital heart disease (including PAVSD): mothers who have a CC genotype at position 677 of the MTHFR gene have an increased chance of having a CHD-ridden child. Other genes that increase the chance of a child with CHD in smoker mothers who carry genetic variations in them include ERCC1, ERCC5, PARP2, and OSGEP. [42]
There are various ways of diagnosing this congenital heart defect both prenatally and postnatally, these methods include: [44] [45]
When the disorder is detected (usually before or soon after birth), prostaglandin will be temporarily used as soon as possible to keep the ductus arteriosus open for as long as possible until surgery can be done, this is done so that blood can keep flowing to the lungs, since the bodies of babies with pulmonary atresia usually use the ductus arteriosus for lung blood flow pre-natally until birth, after which it closes. [46] [47] [48] [49] [32] [50] [51] [52]
Afterwards, this anomaly is usually managed with surgeries for improvement of blood flow and function of the heart, although what kind of treatment one gets depends on the structure of the cardiorespiratory system. [44] [53] [54] [55] [56]
The surgical methods that can be used to treat (for the long-term) this condition include: [44] [57]
Frequency estimates vary between populations, estimates range from 0.01% to 0.2% of live births with PAVSD. [58] [32] [37] It is believed to make up for 1-2% of cases of congenital heart defects worldwide. [59] [32] [60]
Of all patients with PAVSD, around 25–32% of them have a microdeletion of the 22q11.2 chromosome. [61]
Without treatment, it is a highly life-threatening condition, so prognosis is poor. [35] [34] If surgery isn't performed in severe cases, the child can (and will) die, since the phenotype of pulmonary atresia is not compatible with life due to the pulmonary valve atresia resulting in reduced blood oxygenation. [9] [62] [63]
Life expectancy for untreated children with PAVSD is 10 years. [10] Survival rates for untreated people with this defect have been reported to be 50% at the tenth decade and 10% at the twentieth decade, [56] and out of these untreated patients, those who do not have major aortopulmonary arteries have a higher chance of living to their 30s than those who do have them, as the latter have a 40% chance of surviving to the tenth decade and a 20% chance of doing so to the thirtieth decade. [64]
Prognosis after surgical intervention is generally good. [65]
This combination of birth defects was first described in 1980 by DiChiara et al., their patients were a father and his son from the United States both of which had pulmonary atresia and a ventricular septal defect. Up until that point, there had been no familial cases of PA with a VSD. A multifactorial etiology (that is, a cause involving genetics and the environment) was suspected in these patients and they were offered medical counseling for the condition. [66]
As of 2011, the oldest patient with untreated PAVSD was a 59-year-old woman from Japan. Her condition was discovered in childhood but she refused to get any surgery to treat it (including cardiac catheterization), she developed dyspnea during her teenage years. Radiological studies showed a ventricular septal defect alongside cardiac and arterial anomalies (heart silhouette enlargement, elevation of the cardiac apex, presence of a right aortic arch, enlargement affecting the main pulmonary arteries and their major branches, high pulmonary artery vascularity, and ventricular septal defect). [67]
Cardiology is the study of the heart. Cardiology is a branch of medicine that deals with disorders of the heart and the cardiovascular system. The field includes medical diagnosis and treatment of congenital heart defects, coronary artery disease, heart failure, valvular heart disease, and electrophysiology. Physicians who specialize in this field of medicine are called cardiologists, a sub-specialty of internal medicine. Pediatric cardiologists are pediatricians who specialize in cardiology. Physicians who specialize in cardiac surgery are called cardiothoracic surgeons or cardiac surgeons, a specialty of general surgery.
Tetralogy of Fallot (TOF), formerly known as Steno-Fallot tetralogy, is a congenital heart defect characterized by four specific cardiac defects. Classically, the four defects are:
Patent ductus arteriosus (PDA) is a medical condition in which the ductus arteriosus fails to close after birth: this allows a portion of oxygenated blood from the left heart to flow back to the lungs through the aorta, which has a higher blood pressure, to the pulmonary artery, which has a lower blood pressure. Symptoms are uncommon at birth and shortly thereafter, but later in the first year of life there is often the onset of an increased work of breathing and failure to gain weight at a normal rate. With time, an uncorrected PDA usually leads to pulmonary hypertension followed by right-sided heart failure.
dextro-Transposition of the great arteries is a potentially life-threatening birth defect in the large arteries of the heart. The primary arteries are transposed.
A congenital heart defect (CHD), also known as a congenital heart anomaly, congenital cardiovascular malformation, and congenital heart disease, is a defect in the structure of the heart or great vessels that is present at birth. A congenital heart defect is classed as a cardiovascular disease. Signs and symptoms depend on the specific type of defect. Symptoms can vary from none to life-threatening. When present, symptoms are variable and may include rapid breathing, bluish skin (cyanosis), poor weight gain, and feeling tired. CHD does not cause chest pain. Most congenital heart defects are not associated with other diseases. A complication of CHD is heart failure.
A ventricular septal defect (VSD) is a defect in the ventricular septum, the wall dividing the left and right ventricles of the heart. The extent of the opening may vary from pin size to complete absence of the ventricular septum, creating one common ventricle. The ventricular septum consists of an inferior muscular and superior membranous portion and is extensively innervated with conducting cardiomyocytes.
Transposition of the great vessels (TGV) is a group of congenital heart defects involving an abnormal spatial arrangement of any of the great vessels: superior and/or inferior venae cavae, pulmonary artery, pulmonary veins, and aorta. Congenital heart diseases involving only the primary arteries belong to a sub-group called transposition of the great arteries (TGA), which is considered the most common congenital heart lesion that presents in neonates.
Pulmonary atresia is a congenital malformation of the pulmonary valve in which the valve orifice fails to develop. The valve is completely closed thereby obstructing the outflow of blood from the heart to the lungs. The pulmonary valve is located on the right side of the heart between the right ventricle and pulmonary artery. In a normal functioning heart, the opening to the pulmonary valve has three flaps that open and close.
Persistent truncus arteriosus (PTA), often referred to simply as truncus arteriosus, is a rare form of congenital heart disease that presents at birth. In this condition, the embryological structure known as the truncus arteriosus fails to properly divide into the pulmonary trunk and aorta. This results in one arterial trunk arising from the heart and providing mixed blood to the coronary arteries, pulmonary arteries, and systemic circulation. For the International Classification of Diseases (ICD-11), the International Paediatric and Congenital Cardiac Code (IPCCC) was developed to standardize the nomenclature of congenital heart disease. Under this system, English is now the official language, and persistent truncus arteriosus should properly be termed common arterial trunk.
Tricuspid atresia is a form of congenital heart disease whereby there is a complete absence of the tricuspid valve. Therefore, there is an absence of right atrioventricular connection. This leads to a hypoplastic (undersized) or absent right ventricle. This defect is contracted during prenatal development, when the heart does not finish developing. It causes the systemic circulation to be filled with relatively deoxygenated blood. The causes of tricuspid atresia are unknown.
A right-to-left shunt is a cardiac shunt which allows blood to flow from the right heart to the left heart. This terminology is used both for the abnormal state in humans and for normal physiological shunts in reptiles.
Interrupted aortic arch is a very rare heart defect in which the aorta is not completely developed. There is a gap between the ascending and descending thoracic aorta. In a sense it is the complete form of a coarctation of the aorta. Almost all patients also have other cardiac anomalies, including a ventricular septal defect (VSD), aorto-pulmonary window, and truncus arteriosus. There are three types of interrupted aortic arch, with type B being the most common. Interrupted aortic arch is often associated with DiGeorge syndrome.
Aortopulmonary window (APW) is a faulty connection between the aorta and the main pulmonary artery that results in a significant left-to-right shunt. The aortopulmonary window is the rarest of septal defects, accounting for 0.15-0.6% of all congenital heart malformations. An aortopulmonary window can develop alone or in up to 50% of cases alongside other cardiac defects such as interrupted aortic arch, coarctation of the aorta, transposition of great vessels, and tetralogy of Fallot.
Aortopulmonary septal defect is a rare congenital heart disorder accounting for only 0.1-0.3% of congenital heart defects worldwide. It is characterized by a communication between the aortic and pulmonary arteries, with preservation of two normal semilunar valves. It is the result of an incomplete separation of the aorticopulmonary trunk that normally occurs in early fetal development with formation of the spiral septum. Aortopulmonary septal defects occur in isolation in about half of cases, the remainder are associated with more complex heart abnormalities.
Anomalous pulmonary venous connection is a congenital defect of the pulmonary veins.
Hypoplastic right heart syndrome or HRHS is a congenital heart defect in which the structures on the right side of the heart, particularly the right ventricle, are underdeveloped. This defect causes inadequate blood flow to the lungs, and thus a cyanotic infant.
Major aortopulmonary collateral arteries are arteries that develop to supply blood to the lungs when native pulmonary circulation is underdeveloped. Instead of coming from the pulmonary trunk, supply develops from the aorta and other systemic arteries.
Absent pulmonary valve syndrome(APVS) is a congenital heart defect that occurs when the flaps of the pulmonary valve do not develop or are severely underdeveloped (hypoplasia) resulting in aneurysms (dilation) of the pulmonary arteries and softening of the trachea and bronchi (tracheobronchomalacia). Usually, APVS occurs together with other congenital heart defects, most commonly ventricular septal defect and right ventricular outflow tract obstruction. It is sometimes considered a variant of Tetralogy of Fallot. The first case of absent pulmonary valve syndrome was reported Crampton in 1830.
The Yasui procedure is a pediatric heart operation used to bypass the left ventricular outflow tract (LVOT) that combines the aortic repair of the Norwood procedure and a shunt similar to that used in the Rastelli procedure in a single operation. It is used to repair defects that result in the physiology of hypoplastic left heart syndrome even though both ventricles are functioning normally. These defects are common in DiGeorge syndrome and include interrupted aortic arch and LVOT obstruction (IAA/LVOTO); aortic atresia-severe stenosis with ventricular septal defect (AA/VSD); and aortic atresia with interrupted aortic arch and aortopulmonary window. This procedure allows the surgeon to keep the left ventricle connected to the systemic circulation while using the pulmonary valve as its outflow valve, by connecting them through the ventricular septal defect. The Yasui procedure includes a modified Damus–Kaye–Stansel procedure to connect the aortic and pulmonary roots, allowing the coronary arteries to remain perfused. It was first described in 1987.
Life expectancy when untreated < 10 years