Truncus arteriosus

INTRODUCTION — Truncus arteriosus (TA), also known as common arterial trunk, is a cyanotic congenital heart defect. In this condition, blood is pumped from the heart through a single truncal valve into a truncal artery, which collectively gives rise to the aorta and the pulmonary arteries (figure 1).

The anatomy, clinical manifestations, diagnosis, and management of TA will be reviewed here.

EPIDEMIOLOGY — The reported incidence of TA ranges from 6 to 10 per 100,000 live births [1,2]. Although only 0.7 percent of all congenital heart lesions are due to TA, it accounts for 4 percent of all critical congenital heart disease cases [1].

EMBRYOLOGY — During the early stages of a normally developing heart, the great arteries originate from a single truncal root. A wall forms within this root (truncoconal septum) that divides the root into a fully developed main pulmonary artery and ascending aorta by the end of the fifth week of gestation. Over the next two weeks of development, there is closure of the conal (infundibular) septum as the truncoconal septum fuses with the endocardial cushions and the interventricular septum, which separates the newly formed right and left ventricle.

Disturbances in the development of the truncoconal septum result in a range of conotruncal abnormalities including TA. The lack of wall development also impairs the creation of separate aortic and pulmonary valves, resulting in the single truncal valve associated with TA [3].

Neural crest cells and derangements in neural tube development have been associated with the development of TA and other conotruncal malformations [4,5]. (See 'Pathogenesis' below.)

ANATOMY — In patients with TA, there is a common arterial trunk that is positioned above the ventricular septum. This sole trunk provides blood for the entire systemic, pulmonary, and coronary artery circulation. In the repaired or unrepaired state, the truncal artery is generally larger in diameter than the normal aorta at a given age. Other associated findings are common and include truncal valve and aortic arch abnormalities.

●Truncal valve – In TA, there is a single semilunar valve. Valve anatomy is variable. In a review of 400 cases the relative frequency of different valve morphologies was as follows [6]:

•Trileaflet – 69 percent

•Quadricuspid – 22 percent

•Bicuspid – 9 percent

Leaflets are generally thickened and can be deficient in size or restricted in motion. These combinations can result in an incompetent valve with varying degrees of stenosis or regurgitation, although the latter is more frequently encountered.

●Aortic arch anomalies – In patients with TA, aortic arch anomalies are common and include the following, in order of frequency [7-11]:

•Right aortic arch – 21 to 36 percent

•Interrupted aortic arch – 11 to 19 percent

•Hypoplastic aortic arch (with or without coarctation of the aorta) – 3 percent

A patent ductus arteriosus (PDA) is especially important in patients with an interrupted or hypoplastic aortic arch as it provides blood flow to the descending aorta, thereby preventing severe life-threatening heart failure due to low cardiac output.

●Ventricular septal defect – In most patients, there is a malalignment large ventricular septal defect (VSD). This combination of a single overriding great artery, VSD, and frequent right-side aortic arch is similar to that seen in patients with tetralogy of Fallot and pulmonary atresia.

●Coronary artery anomalies – In patients with TA, the artery origins are often abnormal [12]. The coronary artery pattern is highly variable and there is no particular pattern associated with TA. These variations are important considerations for surgical repair.

●Conduction abnormalities – There may be associated variations in the conduction system, which also affects surgical repair. The location and structure of the sinus node and atrioventricular node are normal, but the atrioventricular bundle course may vary and is generally dependent on the location of the VSD [13].

●Other abnormalities – Other cardiac anomalies that have been observed include secundum atrial septal defect (9 to 20 percent), mild tricuspid stenosis (6 percent), aberrant subclavian arteries (4 to 10 percent), and a persistent superior vena cava draining into the coronary sinus (4 to 9 percent) [9,14]. A PDA is present in approximately half of the patients with TA.

CLASSIFICATION — Different forms of TA are classified based upon the pulmonary arterial architecture and the presence of aortic anomalies. The most commonly used classification schemas are the Collett and Edwards (CE) and Van Praagh (VP) (figure 1) [15-17]:

●Collet and Edwards classification – The CE classification, the first proposed and most simple system, consists of the following four classes based on pulmonary architecture (figure 1) [16]:

•In type I, a main pulmonary artery is present and arises from the left side of the truncal root.

•In type II, the right and left branch pulmonary arteries have two closely spaced but separate origins from the posterior aspect of the truncal root.

•In type III, the branch pulmonary artery origins are widely separated from the truncal root.

•In the original type IV, the pulmonary arteries originate from the descending aorta. Patients in this category, however, are now considered to have a different form of congenital heart disease called pulmonary atresia [18]. (See "Pulmonary atresia with intact ventricular septum (PA/IVS)".)

●Van Praagh classification – The VP classification is similar to the CE schema; however, it also includes aortic abnormalities and unilateral pulmonary atresia, which are particularly important for surgical repair (figure 1) [17].

•Type A1 is the same as CE type 1, in which a main pulmonary artery is present and arises from the left side of the truncal root.

•Type A2 includes both CE types II and III, as the two CE types do not differ embryologically and the surgical approach is the same. Type A2 consists of right and left branch pulmonary arteries with separate origins (regardless of the distance separating the two pulmonary arteries) from the truncal root.

•In type A3, there is unilateral pulmonary atresia with collateral supply to the affected lung.

•In type A4, the truncus is associated with an interrupted aortic arch.

●Society of Thoracic Surgeons modification – In 2000, the following modification of the VP schema into three categories was proposed by members of the Society of Thoracic Surgeons Congenital Heart Surgery Database committee and European Association for Cardiothoracic Surgery. This classification is primarily used by pediatric cardiovascular surgeons.

•TA with confluent or near confluent pulmonary arteries (large aorta type, VP types A1 and A2)

•TA with absence of one pulmonary artery (VP type A3)

•TA with interrupted aortic arch or coarctation (large pulmonary type, VP type A4)

PATHOGENESIS — Although the cause of TA is unknown, limited data suggest both environmental and genetic factors contribute to its pathogenesis as follows:

●In a case-control study from the Baltimore-Washington Infant Study, self-reported first trimester maternal cigarette consumption was associated with an increased risk of TA (odds ratio 1.9, 95% CI 1.04-3.45) [19].

●A study based on data from the Texas Birth Defects Registry (1999 to 2004) reported an association of nonsyndromic TA with advancing maternal age and maternal residence on the Texas-Mexico border [20].

●Conotruncal anomalies including TA are associated with 22q11.2 deletions [21-24]. Deletions in three genes in this locus (TBX1, CRKL, and ERK2) cause neural crest cell and anterior heart anomalies seen in patients with DiGeorge syndrome [21]. It appears that 22q11.2 deletions are associated with one of every four to five cases of TA [23,25]. (See "DiGeorge (22q11.2 deletion) syndrome: Clinical features and diagnosis", section on 'Cardiac anomalies' and "DiGeorge (22q11.2 deletion) syndrome: Epidemiology and pathogenesis", section on 'Chromosome 22q11.2'.)

PHYSIOLOGY — The normal transition at birth results in changes in pulmonary vascular resistance (PVR) and blood flow that affect TA pathophysiology and its clinical manifestations. In the newborn infant, PVR is initially high, with relatively little left-to-right shunting at birth. The amount of flow into the pulmonary arteries is relatively normal and is almost equal to the systemic cardiac output. Over the first several weeks of life, however, the PVR drops and left-to-right shunting increases to the point that heart failure occurs. While the shunt is similar to that of isolated ventricular septal defects (VSD), heart failure usually presents earlier in patients with TA. This is because diastolic pressures are higher in the great arteries than in the ventricles, which leads to a greater degree of shunting throughout the cardiac cycle with TA (whereas, with a VSD, shunting occurs predominantly during systole).

Regardless of age, there is mixing of the systemic and pulmonary venous blood flow at the intracardiac and arterial levels, resulting in mild or moderate cyanosis.

Pulmonary vascular obstructive disease may develop in surgically uncorrected patients with large pulmonary blood flow, with changes noted as early as six months of age. (See "Physiologic transition from intrauterine to extrauterine life", section on 'Transition at delivery' and "Heart failure in children: Etiology, clinical manifestations, and diagnosis", section on 'Volume overload with preserved ventricular contractility'.)

In patients with significant amounts of truncal valve regurgitation, there is an increased risk of coronary artery ischemia and ventricular dysfunction due to the combination of lower diastolic blood pressures and increased ventricular myocardial oxygen demands of the additional volume load. These factors increase the likelihood and severity of heart failure.

Neonates with interrupted aortic arch or critical coarctation are at risk for heart failure when the ductus arteriosus closes as the ventricular outflow obstruction leads to pressure overload. In these patients, patency of the ductus arteriosus is critical to decrease pressure overload and provide distal blood flow. (See "Heart failure in children: Etiology, clinical manifestations, and diagnosis", section on 'Pressure overload with preserved ventricular contractility' and "Clinical manifestations and diagnosis of coarctation of the aorta", section on 'Neonates'.)

NATURAL HISTORY — The outcome of TA without surgical repair is generally dismal, though there are occasional reports of survivors with unoperated TA. Case series of uncorrected patients have reported an average age of death of five weeks with only 15 percent surviving to the age one year [26]. Although long-term data on the natural history prior to surgical correction are sparse, it appears that all patients who survive beyond the first year of life subsequently develop severe pulmonary vascular obstructive disease (ie, Eisenmenger syndrome) with profound cyanosis and functional impairment [27,28]. (See "Pulmonary hypertension with congenital heart disease: Clinical manifestations and diagnosis".)

CLINICAL MANIFESTATIONS

Presentation — Most patients with TA present within the first weeks of life with cyanosis, respiratory distress due to pulmonary congestion and heart failure, and/or a heart murmur.

●Cyanosis – Over the first days of life, mild or moderate cyanosis can be present and may be the only initial sign of TA. In some cases, cyanosis may not be discernible by physical examination but desaturation may be detected by pulse oximetry screening during the birth hospitalization. (See "Newborn screening for critical congenital heart disease using pulse oximetry".)

●Pulmonary congestion and heart failure – During the next several days to weeks as pulmonary arterial resistance falls, the unrestricted and large amount of pulmonary blood flow produces symptoms of pulmonary congestion and heart failure. Clinical features include poor feeding, lethargy, signs of respiratory distress (tachypnea, costal-sternal retractions, grunting, and nasal flaring), tachycardia, hyperdynamic precordium, and hepatomegaly. (See "Heart failure in children: Etiology, clinical manifestations, and diagnosis", section on 'Clinical manifestations'.)

●Cardiovascular findings – In unrepaired TA patients, the second heart sound is loud and single, but this may be hard to appreciate in a tachycardiac neonate. A prominent ejection click is frequently heard at the apex or left sternal border. There is usually a systolic ejection murmur at the left sternal border. Peripheral pulses are accentuated and often bounding. The pulse pressure usually is increased because of runoff into the pulmonary vascular bed during diastole.

In patients with truncal valve regurgitation, a diastolic high-pitched murmur may be heard along the left sternal border.

Noncardiac findings — As noted above, a considerable number of patients with TA have 22q11.2 deletion syndrome [21-24]. These patients may present with clinical features of DiGeorge syndrome, including hypocalcemia due to parathyroid hypoplasia, hypoplastic thymus, and palatal abnormalities (eg, cleft palate). (See "DiGeorge (22q11.2 deletion) syndrome: Clinical features and diagnosis".)

Electrocardiogram findings — The electrocardiogram (ECG) in patients with TA is nonspecific and may be normal, especially in the neonate. In some cases, there is evidence of left or right ventricular hypertrophy, or a combination of both. In patients with heart failure related to pulmonary overcirculation, QRS and P-wave voltages can be increased.

Chest radiography findings — In patients with TA, chest radiography typically shows cardiac enlargement and increased pulmonary vascular markings. Other findings include a right aortic arch in approximately one-third of patients and an absent thymus in patients with TA associated with DiGeorge syndrome. (See 'Anatomy' above.)

DIAGNOSIS — The diagnosis of TA is confirmed by echocardiography.

Prenatal diagnosis — Fetal echocardiography can diagnose TA by identifying the origin of the central main pulmonary artery or proximal pulmonary branch from the ascending truncal root. However, when these cannot be conclusively ascertained, it can be difficult to distinguish TA from other conotruncal cardiac lesions, such as tetralogy of Fallot with pulmonary atresia (TOF-PA) and aortic atresia [29,30].

In a single-center case series of 136 patients with TA, 43 patients (32 percent) were diagnosed prenatally [29]. In this cohort, five patients with TA were initially misdiagnosed with TOF-PA. In contrast, five patients initially diagnosed with TA were subsequently found to have either TOF-PA or double-outlet right ventricle. Of the 43 fetuses diagnosed prenatally, there were 24 live births, 17 elective terminations, and 2 lost to fetal demise. Of the live-born infants, four died in the newborn period without attempted surgical repair, including three with nonspecified extracardiac abnormalities, which were the primary cause of death.

In another series of 17 patients, valve abnormalities such as regurgitation helped distinguish TA from pulmonary atresia [31].

Despite the challenges, it remains desirable to make a prenatal diagnosis of TA so that the delivery of the affected fetus can be performed at an institution experienced in the care of neonates with critical congenital heart disease. All neonates with prenatally diagnosed congenital heart disease (including TA) should have the diagnosis confirmed with postnatal echocardiography.

Fetal echocardiography is discussed in greater detail separately. (See "Congenital heart disease: Prenatal screening, diagnosis, and management".)

Postnatal diagnosis — The diagnosis of TA is generally made by echocardiography and is ideally made soon after birth. Echocardiography is performed based on a strong clinical suspicion for congenital heart disease because of findings from a prenatal echocardiography and/or signs of underlying cardiac disease, including cyanosis (by inspection or by abnormal pulse oximetry screening), respiratory distress, or other physical findings suggestive of heart failure (eg, tachycardia and heart murmur). (See 'Presentation' above and "Identifying newborns with critical congenital heart disease".)

The echocardiographic diagnosis is made by identifying a single overriding great vessel arising from the heart, typically from a subcostal long-axis view. Subcostal imaging also provides information on the status of the atrial and ventricular septae, atrioventricular and truncal valves, and the truncal root and pulmonary artery branch anatomy. Doppler techniques such as color mapping can quantify the degree of truncal valve regurgitation and stenosis. In addition, echocardiography identifies the location and origin of coronary arteries and evaluates the anatomy of the ascending and descending aorta.

Due to the advances in echocardiography, cardiac catheterization is now used mainly for interventions and is no longer employed as a first-line modality to diagnose newborns with TA.

MANAGEMENT

Initial medical management — The initial management of TA is to stabilize cardiopulmonary function for the patient prior to surgery, particularly in those with heart failure. Patients with TA are at risk for severe heart failure and generally require care in the intensive care unit. Interventions include the following and are discussed in greater detail separately:

●Diuretic therapy provides relief of volume overload symptoms, including pulmonary congestion. In the neonate with heart failure, diuretic agents include loop (eg, furosemide) and thiazide diuretics. (See "Heart failure in children: Management", section on 'Diuretics'.)

●Inotropic agents (eg, dopamine and dobutamine) improve myocardial contractility. (See "Heart failure in children: Management", section on 'Inotropes'.)

●Angiotensin blockade reduces afterload, thereby improving cardiac function. In children, angiotensin-converting enzyme inhibitors are the preferred agents. (See "Heart failure in children: Management", section on 'ACE inhibitors'.)

●Noninvasive positive pressure ventilation is often used in patients with respiratory distress due to pulmonary congestion. In more severe cases, intubation and mechanical ventilation may be required because of impending respiratory failure. (See "Heart failure in children: Management", section on 'Noninvasive ventilation'.)

●Additional supportive care to correct metabolic acidosis, hypoglycemia, and anemia that may contribute to heart failure. (See "Heart failure in children: Management", section on 'General measures'.)

It is also imperative to identify patients with interrupted or critical coarctation of the aorta as these patients are at risk for developing acute severe heart failure and death when the ductus arterious closes. Such patients require prompt initiation of prostaglandin E1 (alprostadil) to keep the ductus arteriosus open. (See "Management of coarctation of the aorta", section on 'Neonates with critical coarctation'.)

Surgical repair — Primary surgical repair during the neonatal period has led to improved survival in patients with TA. In the modern era, one-year survival following surgical repair of TA is >80 percent, whereas the observed one-year survival in uncorrected TA is approximately 15 percent [32-34]. (See 'Natural history' above and 'Survival' below.)

Primary surgical repair is performed while patients are in deep hypothermia and placed on low-flow continuous cardiopulmonary bypass or intermittent periods of circulatory arrest.

The procedure encompasses the following steps (figure 2):

●The pulmonary arteries are mobilized from the truncus and, subsequently, typically reattached to a right ventricle to pulmonary artery conduit

●Opening and repair of the truncus with either a patch of pulmonary homograft material or pericardium

●Closure of the ventricular septal defect with a prosthetic patch

An alternate surgical option is initial palliative pulmonary arterial banding, which restricts pulmonary overcirculation, allowing the infant to grow larger. Complete repair is then deferred until late infancy. However, this procedure requires two operations and does not provide any benefit in regard to long-term mortality and morbidity [35]. As a result, given the incremental surgical morbidity of a two-stage process, we suggest primary repair as the preferred approach.

FOLLOW-UP CARE

Overview — After primary repair of TA, patients require long-term routine care that is individually planned through the primary caregiver in collaboration with a pediatric cardiologist. Clinicians need to know the potential complications following surgical repair.

Routine follow-up care includes the following:

●A focused history and physical examination should be performed at each visit. The interval history and examination focus on identifying any signs and symptoms of heart failure, conduit obstruction (eg, exercise intolerance, dyspnea, peripheral edema), and/or arrhythmias (eg, palpitations, syncope).

●Serial echocardiographic assessments and additional testing based on the clinical and echocardiographic findings. (See 'Follow-up testing' below.)

●Neurodevelopmental screening – Children with TA are at risk for developmental impairment and should undergo appropriate surveillance, screening, and/or referral [36]. (See "Developmental-behavioral surveillance and screening in primary care".)

●Endocarditis prophylaxis, if warranted. (See 'Endocarditis prophylaxis' below and "Prevention of endocarditis: Antibiotic prophylaxis and other measures".)

●Counseling regarding physical activity and sports participation. (See 'Activity' below.)

Follow-up testing — Routine testing can include:

●Echocardiography – Serial echocardiography is performed to evaluate the surgical connection between the right ventricle and pulmonary arteries, size and function of the right and left ventricles, and presence or absence of any residual ventricular or atrial level shunts. Truncal valve stenosis and/or regurgitation should also be assessed.

●Chest radiography – Chest radiography is not a routine part of longitudinal follow-up, but it may be performed if there is a particular concern (eg, acute pulmonary symptoms). In repaired TA, both the cardiac silhouette and the pulmonary vasculature are evaluated. Asymmetric distribution of blood to either lung can be detected by the relative degree of vascularity in the lungs. While nonspecific, cardiomegaly can also be a sign of hemodynamically important lesions such as residual defects, regurgitation, or ventricular dysfunction.

●Cardiac magnetic resonance imaging or computed tomography scan quantifies ventricular sizes and function. Branch pulmonary arteries and conduit calibers can also be evaluated with these modalities, especially if they are poorly visualized by echocardiography.

●Cardiopulmonary exercise testing can be performed in patients to quantify the degree of exercise tolerance or if the health care provider is trying to determine whether or not signs and symptoms are cardiac related [37]. (See "Exercise capacity and VO2 in heart failure".)

Endocarditis prophylaxis — Prophylactic antibiotics for endocarditis are recommended in the following circumstances (see "Prevention of endocarditis: Antibiotic prophylaxis and other measures"):

●Patients who have undergone surgical TA repair with prosthetic material during the first six months after the procedure

●Patients who have undergone surgical TA repair and have residual defects at the site or adjacent to the site of the prosthetic material

●Patients with prior episodes of endocarditis

●Patients with cyanosis (ie, unrepaired TA)

Activity — There are few data to help guide decisions about physical activity and sports participation for children who have undergone primary repair of TA. Based on our clinical experience, we encourage aerobic exercise in asymptomatic patients with no residual obstruction, no right ventricular hypertension, or tachyarrhythmias. We instruct patients to self-limit exercise (ie, discontinue if they feel fatigued). Competitive sports activities with a high static (isometric) component (eg, rock climbing, power lifting) are discouraged.

Patients with a brief episode of supraventricular tachycardia or extrasystolic isolated beats do not require additional restrictions to physical activity.

For patients with additional cardiac lesions and those who have undergone cardiac intervention or surgical procedures in addition to TA repair, decisions are individualized.

A detailed discussion of physical activity and exercise in patients with congenital heart disease, including the use of cardiorespiratory assessments and the distinction between recreational versus competitive activities, is provided separately. (See "Physical activity and exercise in patients with congenital heart disease".)

OUTCOME

Survival — Primary surgical repair has improved the survival of patients with TA. Reported perioperative mortality rates range from 7 to 11 percent [38,39]. Long-term survival following primary repair has also improved [40-42]. In the available reports on long-term survival in patients who underwent TA in the 1980s to 2010s, 10-year survival ranged from 85 to 93 percent [40,41] and 30-year survival was 74 percent [41,42].

Reported risk factors for early mortality (ie, within 30 days of surgery) include [42,43]:

●Extracorporeal membrane oxygenation

●Coronary artery anomaly

●Prior surgical intervention

●Weight <2.5 kg

Reported risk factors for late mortality (ie, after 30 days of surgery) include [39]:

●DiGeorge syndrome

●Need for tracheostomy postoperatively

Cumulative evidence suggests that patients undergoing concomitant truncal valve surgery or repair of interrupted arch at the time of primary TA repair are likely not at increased risk of perioperative mortality; however, the available studies have reached different conclusions [33,38,42,44-46]. In a multicenter retrospective report of 572 patients who underwent primary repair between 2000 to 2009, mortality was greater in patients who required truncal valve surgery compared with those who did not (30 versus 10 percent) [38]. The highest mortality was in patients who underwent repair for both truncal valve and aortic arch interruption (60 percent). In contrast, case series from single centers have not shown an increased risk of mortality in patients requiring truncal valve replacement or repair of an interrupted arch at the time of primary repair [33,38,42,45,46].

Reintervention — After surgical repair, reintervention is common and includes:

●Replacement of right ventricle to pulmonary artery conduits placed in infancy as patients will "outgrow" their conduit, which remains fixed in size. Stenosis may also develop over time due to a combination of calcification and due to patient growth.

●Truncal valve repair or replacement due to worsening stenosis or regurgitation.

In a single-center report of 171 children who underwent operative repair between 1979 and 2014, nearly all surviving patients eventually required reoperation [42]. At 10 years, only 23 percent of patients had not undergone reoperation, and by 20 years only 3 percent had not undergone reoperation. In another multicenter study of 216 patients followed postoperatively for approximately three years, approximately one-half required reintervention (median time to reintervention was 23 months) [39]. Truncal valve dysfunction (moderate degree of regurgitation or worse) prior to TA repair was associated with a higher likelihood of valve reintervention [44,47].

Functional status and quality of life — In long-term follow-up studies of survivors who underwent TA repair in infancy, nearly all had no or only mild limitation in physical activity (ie, New York Heart Association functional class I or II) [42,48].

Data are limited regarding the quality of life of patients who underwent surgical correction of TA. In a small cross-sectional study of 25 patients, results from questionnaires showed both physical health status and health-related quality of life were diminished compared with the general population [49]. Of note, in this cohort the prevalence of 22q11.2 deletions was 32 percent.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Congenital heart disease in infants and children".)

SUMMARY AND RECOMMENDATIONS

●Anatomy – Truncus arteriosus (TA; also known as common arterial trunk) is a cyanotic congenital heart defect in which all blood from the heart is pumped through a single truncal valve into a truncal artery. The ascending truncal artery then gives rise to the aorta and the pulmonary arteries in various configurations (figure 1). TA accounts for a small percentage of all congenital heart disease (CHD). (See 'Anatomy' above and 'Epidemiology' above.)

●Other findings and association with DiGeorge syndrome – Other associated findings are common and include (see 'Anatomy' above):

•Truncal valve abnormalities

•Aortic arch anomalies

•Ventricular septal defects

Approximately 20 to 25 percent of patients with TA have 22q11.2 deletions and may present with other clinical features of DiGeorge syndrome (eg, hypocalcemia, hypoplastic thymus, cleft palate). (See "DiGeorge (22q11.2 deletion) syndrome: Clinical features and diagnosis".)

●Classification – There are several classification schemas used to describe the various forms of TA based on the differences in pulmonary architecture and presence of aortic anomalies (figure 1). (See 'Classification' above.)

●Physiology – The pathophysiology of TA and its clinical manifestations are dependent on the volume of pulmonary blood flow determined by the pulmonary vascular resistance, the degree of truncal valve insufficiency (regurgitation), and whether there are significant aortic anomalies. (See 'Physiology' above.)

●Presentation – Most patients with TA present within the first weeks after birth with cyanosis, respiratory distress due to pulmonary congestion and heart failure, and/or a heart murmur. (See 'Presentation' above.)

●ECG and radiographic findings – Typical nonspecific findings on ECG and chest radiography include cardiac enlargement and increased pulmonary vascular markings. Other chest radiographic findings may include a right aortic arch in one-third of patients or an absent thymus (associated with DiGeorge syndrome).

●Diagnosis – TA is diagnosed by echocardiography by identifying a single overriding great vessel arising from the heart. The diagnosis can be made antenatally; however, it can be difficult to distinguish TA from other conotruncal cardiac lesions.

●Management – The management of TA includes the following:

•Initial medical management – Initial medical management is directed at stabilizing the infant and preparing the patient for surgical repair. Patients with heart failure may require diuretic therapy, inotropic support, angiotensin blockade, and/or positive pressure ventilation. Such patients are best cared for in the intensive care unit setting. In addition, patients with critical coarctation or interrupted aorta require prompt initiation of prostaglandin E1 (alprostadil) to maintain patency of the ductus arteriosus.

•Surgical correction – Surgical repair is performed in the neonatal period. We suggest primary surgical repair in early infancy, rather than initial palliative pulmonary arterial banding followed by complete repair later in life (Grade 2C). (See 'Surgical repair' above.)

●Outcome – Survival has improved considerably for patients with TA managed in the modern surgical era. Perioperative mortality is approximately 10 percent. However, most patients require reintervention. (See 'Outcome' above.)

●Follow-up care – Patients who have undergone TA repair require longitudinal follow-up care by a cardiologist with expertise in CHD. (See 'Follow-up care' above.)