Congenitally corrected (L-looped) transposition of the great arteries (ccTGA): Management and outcome

INTRODUCTION — 

Congenitally corrected transposition of the great arteries (ccTGA; also called L-looped TGA [L-TGA], double discordance, or ventricular inversion) is a rare form of congenital heart disease (CHD) characterized by atrioventricular (AV) and ventriculoarterial discordance (figure 1).

ccTGA usually does not present with cyanosis unless there are other associated cardiac defects. In ccTGA, blood flows in the correct physiologic direction, resulting in normal oxygenation of the systemic venous return via the abnormally placed ventricles and great arteries. However, patients with ccTGA are at risk of developing heart failure in adulthood due to progressive decline in systemic right ventricular (RV) function.

The management and outcome of ccTGA will be presented here. The anatomy, pathophysiology, clinical features, and diagnosis of ccTGA are discussed separately. (See "Congenitally corrected (L-looped) transposition of the great arteries (ccTGA): Anatomy, clinical features, and diagnosis".)

D-looped TGA (D-TGA) is also discussed separately. (See "D-transposition of the great arteries (D-TGA): Anatomy, clinical features, and diagnosis" and "D-transposition of the great arteries (D-TGA): Management and outcome".)

SURGICAL MANAGEMENT

Overview — There has been a paradigm shift in the management of ccTGA (figure 1) from a "physiologic-based" management approach (wherein atrioventricular [AV] and ventriculoarterial discordance are maintained and surgical intervention is performed only to address associated cardiac defects) to an "anatomic" repair, which makes the morphologic left ventricle (LV) become the systemic ventricle and the morphologic right ventricle (RV) the pulmonary ventricle. Anatomic repair involves more complex surgical interventions and may require LV retraining. These two approaches (anatomic and physiologic-based), including their associated complications and outcomes, are discussed below. (See 'Anatomic repair' below and 'Physiologic-based approach' below.)

The optimal surgical approach for patients with ccTGA is uncertain as there are limited data to inform decision-making. The rationale for anatomic repair is based upon the theory that functional status in adulthood may be improved with this approach. As long-term data on outcomes after anatomic repair become available, there will be a better understanding of whether this approach does in fact improve long-term prognosis, particularly regarding quality of life, functional status, and other morbidities that can result from atrial and arterial switches (tachyarrhythmias, AV block, baffle obstructions, neo-aortic regurgitation, and LV dysfunction). (See 'After anatomic repair' below.)

Our approach — Decisions regarding the choice of surgical repair in patients with ccTGA are individualized based on the patient's age, anatomy, and degree of symptoms. Our general approach is as follows:

●Pediatric patients – The management approach in children depends upon whether the child has isolated ccTGA or if there are associated defects that impose additional demand on the systemic RV (eg, clinically significant ventricular septal defect [VSD], LV outflow tract [LVOT] obstruction, and/or Ebstein-like malformation of the tricuspid valve). Most patients with ccTGA have other associated defects, most commonly a VSD; isolated ccTGA is relatively uncommon (accounting for <10 percent of cases).

•Patients with associated defects – For pediatric patients with ccTGA associated with lesions that impose additional demand on the systemic RV (eg, clinically significant VSD, LVOT obstruction, and/or Ebstein-like malformation of the tricuspid valve), we suggest anatomic repair. These patients are at greatest risk for developing systemic heart failure with the physiologic approach (wherein AV and ventriculoarterial discordance are maintained and surgical intervention is performed only to address the associated cardiac defects).

If a patient requires LV retraining with pulmonary artery (PA) band placement, this should be performed early in childhood. (See 'Pulmonary artery banding' below.)

•Patients with isolated ccTGA – In pediatric patients with isolated ccTGA, the choice of anatomic repair versus observation is controversial. The surgical procedures are complex, require substantial time on cardiopulmonary bypass, and incur risk of perioperative morbidity and mortality, while their long-term outcome remains uncertain. However, there are also risks associated with foregoing surgical anatomic correction. Patients with isolated ccTGA who do not undergo anatomic repair are at risk for developing heart failure in adulthood, though the risk is lower in this population compared with patients who have additional associated lesions that impose additional demand on systemic RV [1,2].

Based on the available data, our approach is to discuss with the family the potential benefits and complications of the proposed surgical procedures and the areas of uncertainty. The final decision is individualized based on our overall assessment of the patient's potential for heart failure without anatomic correction versus the potential complications of the anatomic repair, as well as the preference of the family.

●Adult patients – Patients who are diagnosed with ccTGA in adulthood usually present with heart failure, systemic AV valve (morphologic tricuspid valve) regurgitation, or arrhythmias. Patients with systemic AV valve regurgitation should be referred for valve surgery before they develop progressive ventricular dysfunction (ie, systemic ventricle [morphologic RV] ejection fraction <40 percent) [3]. PA banding has been found to improve systemic AV valve regurgitation in select patients. (See 'Pulmonary artery banding' below.)

Cardiac transplantation or ventricular assist device placement should be considered in patients with persistent heart failure refractory to these surgical options and standard medical management.

Anatomic repair — Anatomic repair of ccTGA focuses on making the morphologic LV the systemic ventricle and the morphologic RV the pulmonary ventricle. This generally requires equally sized ventricles and a morphologic LV that is prepared (ie, sufficiently hypertrophied or "trained") to take over the workload of the systemic ventricle, thereby minimizing the likelihood of postoperative LV failure.

Choice of procedure — The general approach to surgical decision-making is as follows:

●Step 1: Determine need for PA banding – In patients in whom the LV is not initially ready to become the systemic ventricle, PA banding is used to "train" the LV. (See 'Pulmonary artery banding' below.)

PA banding is often not required in infants who have significant pulmonary stenosis, pulmonary hypertension, or an unrestrictive VSD. In these patients, the LV is already functioning at pressure levels consistent with what will be required as the systemic ventricle.

●Step 2: Select a definitive surgical intervention – The choice of definitive surgical intervention for anatomic correction of the ventricles is largely dependent on the presence of subpulmonary obstruction and the anatomy of the VSD:

•Double switch operation involves atrial and arterial switch components and is performed in patients without significant subpulmonary obstruction. (See 'Double switch operation' below.)

•Senning-Rastelli procedure is performed in patients with a large VSD and LVOT obstruction. It involves creating an intra-atrial baffle (Senning tunnel), closing the VSD with a baffle that directs blood flow from the LV into the aorta, and placing a conduit between the RV and PA (Rastelli procedure). (See 'Senning-Rastelli procedure' below.)

The individual components of these procedures have also been used for anatomic correction in patients with D-Looped TGA, as discussed separately. (See "D-transposition of the great arteries (D-TGA): Management and outcome", section on 'Mustard and Senning procedures' and "D-transposition of the great arteries (D-TGA): Management and outcome", section on 'Rastelli procedure'.)

Pulmonary artery banding — PA banding may be used in patients with ccTGA for either of the following purposes (the first is more common):

●To "train" the LV – In ccTGA patients with an LV that is not ready to function as the systemic ventricle, placement of a band on the PA is used to increase the afterload of the morphologic LV. This exposure to near-systemic pressure increases the LV posterior wall thickness (ie, LV "training") [4-6]. Altering the LV and RV pressure ratio may also reduce the RV sphericity and improve the geometry of the RV prior to anatomic correction [7]. Several case series have shown that PA banding stabilizes systemic AV valve regurgitation and improves systemic ventricular function [7-9]. Typically, PA banding appears to be more successful in younger patients, and the younger the patient, the shorter interval required for training [8,10]. Patients older than 16 years of age appear to be unlikely to achieve sufficient LV function to proceed to anatomic correction [4].

Although pediatric cardiac surgical centers use varying measurements to determine if a morphologic LV is adequately prepared for the systemic circulation, most published reports suggest that a morphologic LV pressure of 66 to 90 percent of systemic pressure is sufficient [11,12]. Serial echocardiograms and cardiac catheterizations are recommended to determine that sufficient LV pressure is obtained prior to surgical correction. In addition, others recommend that normal LV mass and thickness for systemic function using echocardiography and/or magnetic resonance imaging be required prior to anatomic correction [13]. Repeat banding is often required when the PA band has become too "loose" and the goals for LV pressure have not been met. Risk factors for failure of PA band retraining include mild LV dysfunction before banding, development of significant LV dilation and dysfunction, and postoperative development of tricuspid regurgitation [4,12].

The reported median time from PA banding to the double switch procedure ranges from 2 to 29 months [6,10-15]. One center reported the results of LV training using a threshold of 90 percent systemic pressure for the LV with a median interval of 29 months before the double switch [12]. Of the 56 patients with ccTGA who completed training, 91 percent met this threshold of successful LV retraining. Of the 45 patients who underwent a double switch procedure in this cohort, survival was 98 percent at a median follow-up of 30 months; there was one death following transplantation.

●To reduce pulmonary blood flow in patients with large VSDs – In infants with a large unrestrictive VSD, an increase in pulmonary blood flow may result in heart failure in the first few weeks of life as the pulmonary vascular resistance falls. The placement of a PA band can be considered in patients who are refractory to medical management. Creating increased resistance to the pulmonary circuit will reduce pulmonary blood flow, improve the symptoms of heart failure, and promote weight gain. Promotion of growth is desired since anatomic surgical correction is easier to perform in a larger infant. (See "Isolated ventricular septal defects (VSDs) in infants and children: Anatomy, clinical features, and diagnosis", section on 'Size of defect'.)

Double switch operation — The double switch operation consists of an atrial switch procedure that creates an intra-atrial baffle (Mustard or Senning procedure) plus an arterial switch operation. The intra-atrial baffle diverts the deoxygenated systemic venous return into the subpulmonary ventricle and oxygenated pulmonary venous return to the subsystemic ventricle. The arterial switch involves transection of both great arteries and then translocating the vessels to the opposite root, similar to the procedure performed for D-TGA requiring coronary artery transfer. (See "D-transposition of the great arteries (D-TGA): Management and outcome", section on 'Arterial switch operation (ASO)'.)

After a double switch procedure, normal concordance is established with systemic deoxygenated blood baffled across the tricuspid valve into the morphologic RV and flow into the PA. In addition, the oxygenated pulmonary venous return is baffled from the left atrium across the mitral valve into the morphologic LV and then pumped across the neo-aorta to the systemic circulation.

This operation is a technically difficult and challenging procedure with a long cardiopulmonary bypass time. Therefore, identifying the ideal surgical timing is a complex issue. Various centers report a median age at the time of surgery that ranges from seven months to six years and a median weight of 9.6 to 19 kg [6,10,12,14,16-20]. Early hospital mortality is reported to range from 0 to 7.4 percent, and reported event-free survival rates are between 70 to 85 percent at 10 years [6,10,14,16-20].

In addition, coronary artery transfer is required. As a result, in patients undergoing this surgical intervention, delineating the coronary anatomy is mandatory.

Senning-Rastelli procedure — In patients with ccTGA who have a VSD and LVOT obstruction, the Senning-Rastelli procedure is typically used. This surgery creates an intra-atrial baffle (Senning tunnel); in addition, the VSD is closed using a baffle directing the blood from the LV into the aorta, and a conduit is placed between the RV and PA (Rastelli procedure). The Rastelli procedure requires a sizable and appropriately located VSD so that the baffle can be placed to redirect blood flow into the aorta. Studies reporting intermediate-term outcomes after Senning-Rastelli repair suggest that this approach is associated with better survival in this group of patients compared with the double switch operation [16]. (See 'Mortality' below.)

This procedure is the same used for patients with D-TGA, VSD, and LVOT obstruction. There are alternative surgeries used to address TGA with VSD and LVOT obstruction (eg, Nakaidoh procedure, Réparation à l'Etage ventriculaire procedure, Yasui procedure); these are beyond the scope of this topic review. (See "D-transposition of the great arteries (D-TGA): Management and outcome", section on 'Rastelli procedure'.)

Over time, the conduits used in a Senning-Rastelli repair become stenotic because they do not grow as the child grows. As a result, patients who undergo this procedure require serial conduit replacements [21]. (See 'Reintervention' below.)

Physiologic-based approach — The physiologic-based management approach (sometimes referred to as "conventional management" or "conventional repair"), maintains AV and ventriculoarterial discordance (ie, the morphologic RV remains the systemic ventricle). Surgical interventions focus on repairing the associated lesions, if present. Using this approach, children with isolated ccTGA do not undergo surgery initially since there are no associated lesions that require intervention. In patients with associated cardiac defects, the initial surgical intervention varies depending on the defect. As examples, a patient with an associated VSD would undergo VSD closure, and a patient with LVOT obstruction would undergo surgical placement of an LV-to-PA conduit. On the other end of the spectrum, patients with complex straddling of AV valves across the ventricular septum or ventricular hypoplasia might undergo single-ventricle palliation.

The physiologic-based approach is associated with increased risk of systemic ventricular (morphologic RV) failure and systemic AV valve (morphologic tricuspid valve) regurgitation in adulthood. AV valve surgery may be required in patients who develop significant AV valve regurgitation [3]. In a case series of 44 adults with isolated ccTGA who were not operated on in childhood and who were followed for a mean 12 years, 68 percent required AV valve surgery after developing moderate to severe regurgitation and ventricular dysfunction [1]. Four patients required cardiac transplantation. Reported risk factors for poor outcome (death or transplantation) in patients with ccTGA undergoing AV valve surgery include preoperative systemic ventricular dysfunction (ie, ejection fraction [EF] <40 percent) and older age at operation [3,22].

Based on these findings, patients with ccTGA who do not undergo anatomic correction should have close monitoring of systemic ventricle (morphologic RV) and systemic AV valve (morphologic tricuspid valve) function. Surgical interventions in these patients may include:

●Early tricuspid valve surgery (ideally performed before systemic ventricular failure develops) [3].

●PA banding, which is an option for adults with ccTGA who have severe systemic tricuspid regurgitation. In this setting, PA banding may decrease regurgitation and serve as a bridge to transplantation or other surgical interventions. (See 'Pulmonary artery banding' above.)

OUTCOME

After anatomic repair

Mortality

●Perioperative mortality – In a meta-analysis of 21 observational studies including 895 patients with ccTGA who underwent anatomic repair, the pooled operative mortality rate was 8 percent [23]. Early mortality is higher for the double switch operation compared with the Senning-Rastelli procedure [16,24].

●Long-term survival – Based on the available case series, long-term survival following anatomic repair appears to be comparable with or perhaps superior to that of the physiologic-based approach [19,24-27]. As long-term follow-up data on these patients continue to accumulate, it may be possible to reach a firmer conclusion as to whether anatomic repair truly improves long-term survival.

In the available studies, reported 10-year survival after anatomic repair ranged from 69 to 95 percent [15,16,20,24,25,27,28]. The wide range likely reflects differences in the era in which the patients underwent repair (with better outcomes in the later era), median age at operation (with better outcomes in studies with younger patients), proportion of patients with associated complex cardiac defects, and relative frequency of the two anatomic repair procedures (double switch and Senning-Rastelli).

It is unclear whether long-term survival differs among patients who undergo double switch versus the Senning-Rastelli procedure; any observed differences may be due to patient factors that influence the choice of procedure more than the impact of the surgery itself. (See 'Choice of procedure' above.)

In two case series including a total of 203 patients who underwent anatomic repair with either double switch (n = 86) or Senning-Rastelli (n = 117), survival rates at 10 to 20 years were approximately 80 to 85 percent in the double switch group versus 75 to 80 percent in the Senning-Rastelli group [16,24]. Rates of freedom from reoperation and arrhythmia were slightly more favorable in the double switch group compared with the Senning-Rastelli group (freedom from reoperation 94 versus 78 percent; freedom from arrhythmia 79 versus 57 percent) [24].

Morbidity — The complications associated with anatomic correction in patients with ccTGA are primarily due to conduction abnormalities (ie, complete heart block and arrhythmias), left ventricle (LV) dysfunction, and neo-aortic regurgitation. In addition, some of the baffle-associated complications seen in patients with D-looped TGA who undergo arterial switch operation repair may also occur in patients with ccTGA who undergo double switch operation. (See "D-transposition of the great arteries (D-TGA): Management and outcome", section on 'Complications after ASO'.)

Conduction abnormalities — Complete heart block and tachyarrhythmias occur in patients with ccTGA due to the abnormal configuration of conduction tissue. In addition, new-onset complete heart block and atrial arrhythmias are common complications postoperatively [14,16,17,19]. In the available case series, approximately 15 to 40 percent of patients required pacemaker implantation [16,19,20,29].

In a case series of 113 patients undergoing anatomic repair with either double switch (n = 68) or Senning-Rastelli (n = 45), 13 percent required preoperative permanent pacemaker implantation (all were in the double switch group) and an additional 13 percent required postoperative pacemaker implantation (two-thirds were in the double switch group and one-third were in the Senning-Rastelli group) [16]. In this cohort, tachyarrhythmias were noted preoperatively in four patients preoperatively and developed postoperatively in an additional four patients (three in the double switch group and one in the Senning-Rastelli group).

Left ventricular dysfunction — Because the central tenet of anatomic repair is based on the assumption that long-term outcome would be improved with reestablishment of atrioventricular (AV) and ventriculoarterial concordance compared with conventional repair, it is important to determine the long-term incidence and severity of morphologic LV function.

Morphologic LV dysfunction occurs in approximately 10 to 20 percent of patients after anatomic repair [8,11,16,19,30]. The underlying cause and risk factors for postoperative LV dysfunction remain uncertain.

In the available case series, approximately 10 to 15 percent of patients developed LV dysfunction postoperatively [8,12,16]. This most commonly occurred in patients who underwent double switch operation, particularly if they underwent pulmonary artery (PA) banding and/or had heart failure prior to surgical intervention [12,16]. One case series reported that performing PA banding before two years of age was associated with a lower risk of subsequent LV dysfunction [8].

In a report of 106 patients managed at the authors' institution with a mean follow-up of 5.2 years, LV function was normal in 70 percent, mildly depressed in 18 percent, and moderately or severely depressed in 12 percent [30]. Risk factors for LV dysfunction included older age at repair, neo-aortic regurgitation, and pacemaker dependence. All 12 patients with moderate to severe LV dysfunction were pacemaker dependent from high-grade or complete heart block. This experience has led the authors' group to place biventricular pacing systems (ie, cardiac resynchronization therapy) to reduce the short-term development of LV dysfunction [19,30].

Further data are necessary to ascertain the long-term LV function after anatomic correction. Determining and correcting the factors that predict poor LV function may improve long-term outcome. In addition, these data may be useful in guiding new surgical innovations for at-risk patients.

Neo-aortic regurgitation — Patients who have undergone an double switch operation are at increased risk for neo-aortic regurgitation [16,31]. In one series of 68 patients repaired with double switch operation who were followed for at least one year, 70 percent had at least mild aortic insufficiency, including six patients (9 percent) with severe aortic insufficiency requiring aortic valve replacement [16].

PA banding is a risk factor for aortic root dilation and neo-aortic regurgitation [18,19,32].

Baffle-associated complications — There are limited reports of baffle-associated complications in patients with ccTGA undergoing anatomic repair; however, baffle-associated complications have been reported frequently in adult patients with D-looped TGA who underwent repair involving an intra-atrial baffle (eg, Mustard or Senning procedure, which are no longer performed). It is reasonable to assume these complications may also occur in adult patients with ccTGA whose surgical repair includes creation of an intra-atrial baffle. These complications are described separately. (See "D-transposition of the great arteries (D-TGA): Management and outcome", section on 'Baffle-associated complications'.)

Reintervention — Patients who undergo surgical repair for ccTGA commonly require reintervention [16,20,33]. In one case series, of 113 patients who underwent anatomic repair at a single institution, 25 percent required reintervention during follow-up that ranged from 1 to 16 years [16]. In the Senning-Rastelli group (n = 45), 34 reinterventions were performed in 16 patients, including 14 conduit changes or ballooning; in the double switch group (n = 68), 41 reinterventions were performed in 13 patients, including six aortic valve replacements, and surgical and catheter reinterventions of the Senning baffle in 14 patients.

In another series of 32 patients who underwent anatomic repair, rates of reoperation at 1, 5, and 10 years were 8, 29, and 39 percent, respectively (excluding pacemaker revisions) [33]. A revision of the Senning baffle was the most common indication for reoperation in this cohort (16 percent of reoperations).

Functional status — Data regarding the long-term functional outcomes following anatomic repair are limited. In a case series of 48 patients who underwent anatomic repair, >90 percent of survivors had New York Heart Association functional class I (no limitation during ordinary activity) at a median follow-up of 59 months [26].

Patients managed with a physiologic-based approach

Morbidity and mortality — The physiologic-based approach (wherein AV and ventriculoarterial discordance are maintained and surgical intervention is performed only to address associated cardiac defects) was previously the management strategy used at most centers (see 'Physiologic-based approach' above). The long-term outcome for individuals managed with this approach is generally less favorable due to progressive systemic ventricle (morphologic RV) dysfunction and heart failure [1,2,34-36].

In a case series from a single center of 121 patients managed with a physiologic-based approach (86 patients underwent surgical interventions for associated defects and the remaining 35 were managed medically), survival at 5, 10, and 20 years was 92, 91, and 75 percent, respectively [35]. Factors that were independently associated with risk of mortality included systemic (RV) ventricular dysfunction and complete AV canal defect.

The largest study reporting long-term outcomes for patients with ccTGA receiving physiologic-based management was a multicenter study of 558 patients with ccTGA who survived to adulthood and were cared for at one of 29 participating adult congenital heart disease (CHD) programs from 2002 through 2022 [36]. Approximately one-half of the patients in the study had isolated ccTGA and one-half had other associated cardiac defects (VSD in 41 percent; pulmonic stenosis in 26 percent); only 16 percent had undergone cardiac surgery in childhood (eg, for VSD closure and/or augmentation of pulmonary blood flow). At the time of the initial evaluation at the adult CHD center (at a median age of 33 years), 35 percent of patients had moderate to severe systemic (RV) ventricular dysfunction, 48 percent had moderate to severe systemic AV valve (tricuspid) regurgitation, and 29 percent had undergone pacemaker implantation. Over median follow-up of 9 years, there were 54 deaths (10 percent), mostly due to heart failure or sudden/arrhythmic death. In addition, 21 patients (4 percent) underwent heart transplantation and/or were placed on mechanical circulatory support. Factors that were independently associated with increased risk of death or cardiac transplantation included older age at initial visit, severe systemic (RV) ventricular dysfunction, and prior heart failure hospitalization.

In another study of 182 adult patients with ccTGA managed with a physiologic-based approach, heart failure was common both in patients with associated cardiac defects and in those with isolated ccTGA [2]. By the age of 45 years, two-thirds of patients with associated defects and one-quarter of patients with isolated ccTGA had developed symptomatic heart failure. The risk of systemic ventricular dysfunction, systemic AV valve (tricuspid) regurgitation, and arrhythmias increased with increasing age. Risk factors for heart failure included tricuspid regurgitation, tricuspid valve surgery, significant arrhythmia, prior cardiac surgery, and pacemaker therapy. In this cohort, most patients with associated cardiac defects (70 percent) had undergone surgical repair of the defect(s) in childhood.  

Functional status — It is difficult to evaluate the effect of the surgical approach on the overall functional status of this heterogeneous cohort of patients.

Several studies have shown that a substantial number of patients with uncorrected ccTGA have impaired exercise capacity and reduced quality of life [2,36-38]. In one study of 238 adult patients with ccTGA who underwent formal exercise testing at median age of 33 years, aerobic capacity was 65 to 75 percent of predicted [36].

In another single-center study, self-reported health status and quality of life were lower in adult patients with unoperated ccTGA compared with a reference group of patients with mild, hemodynamically insignificant cardiac defects [37]. Perceived health status declined with advancing age.

In a study of 127 patients with ccTGA managed with a physiologic-based approach who were followed into their 30s and 40s, 47 percent were asymptomatic, 31 percent reported mild symptoms that did not interfere with normal activities, 15 percent reported having symptoms that interfered with some activities, and 7 percent reported symptoms that interfered with most if not all activities [2].

FOLLOW-UP CARE — 

All patients with ccTGA should have longitudinal follow-up care with a cardiologist experienced in managing congenital heart disease (CHD). Clinicians need to know the potential complications following the various surgical repairs and in unoperated patients. Follow-up routine care includes focused history, physical examination, and detailed imaging study by echocardiography and/or magnetic resonance imaging.

History — The history focuses on the cardiac status of the patient as follows:

●Episodes of syncope or palpitations that may suggest an underlying arrhythmia or complete heart block

●Increasing exercise intolerance suggestive of declining systemic ventricular function or increasing pulmonary artery (PA) obstruction

●Exertional chest pain may suggest coronary artery insufficiency

●Edema of the face and upper extremities suggests superior venal caval obstruction due to a baffle complication seen in the Senning procedure

●Dyspnea may suggest systemic atrioventricular (AV) valve regurgitation or systemic ventricular dysfunction in the adult patient that is unoperated

Physical examination — The physical examination includes:

●Vital signs, particularly the pulse, to determine any irregularity that suggests an underlying arrhythmia

●Cardiac auscultation to detect any murmur (eg, pulmonary stenosis, aortic or tricuspid insufficiency) or gallop (eg, failure)

●Examination for signs of cardiac failure including pulmonary congestion, peripheral edema, and hepatomegaly

Tests — Routine testing includes electrocardiography (ECG) and echocardiography.

ECG is performed yearly to detect and diagnose arrhythmias. ECG is essential to look for complete heart block since there is a 2 percent increased annual risk for the development of complete heart block [39]. Holter or event recorder monitoring may be useful in patients with a history suggestive of arrhythmia.

Routine echocardiography is used to assess ventricular function, detect PA stenosis, and evaluate competency of the neo-aortic valve. Evaluation of the systemic and pulmonary venous baffles can also be performed with echocardiography.

If there are historical features suggestive of ischemia or signs of unexplained depressed ventricular function on echocardiography, coronary artery insufficiency must be considered. Angiography remains the preferred modality to diagnose coronary artery occlusions in patients who undergo the arterial switch operation (ASO).

Cardiac magnetic resonance imaging is an excellent tool to quantify ventricular function. It should be used when evaluating adults who have not undergone repair and can be used to accurately assess left ventricular (LV) thickness and function in those patients who have undergone PA banding. This diagnostic modality is also helpful in identifying fibrosis and scar formation.

Endocarditis prophylaxis — To reduce the risk of endocarditis, patients with repaired ccTGA should maintain good oral hygiene and receive timely treatment of infections. Antibiotic prophylaxis may be required before certain dental, oral, or invasive airway procedures (eg, routine dental cleaning, tooth extraction, adenotonsillectomy) to reduce the risk of infective endocarditis. Prophylaxis is not necessary prior to gastrointestinal procedures (eg, endoscopy, colonoscopy) or genitourinary procedures (eg, cystoscopy, voiding cystourethrogram) unless the patient has an active infection.

Antibiotic prophylaxis prior to relevant procedures is recommended during the first six months after surgical repair. Prophylaxis is also recommended in patients who have prosthetic heart valves, in whom prosthetic material was used for cardiac valve surgery, or if there are residual defects at or adjacent to the site of a prosthetic device or material.

The approach to determining the need for prophylaxis is summarized in the figure (algorithm 1) and discussed in detail separately. (See "Prevention of endocarditis: Antibiotic prophylaxis and other measures".)

Activity — The 2015 scientific statement of the American Heart Association and American College of Cardiology provides competitive athletic participation guidelines for patients with CHD, including ccTGA [40]. We concur with these recommendations but stress that, as with any guidelines, recommendations need to be tailored to the individual patient and a comprehensive evaluation by an experienced clinician is required:

●Before participation in competitive sports, patients with ccTGA should undergo evaluation that includes clinical assessment, ECG, imaging assessment of ventricular function (typically with echocardiogram), and exercise testing.

●In patients with a history of clinically significant arrhythmias or severe ventricular dysfunction, sports participation may be considered on an individual basis based on clinical stability.

●Patients with ccTGA may participate in low- and moderate-intensity (class IA and IB) sports (figure 2) if they do not have clinically significant arrhythmias, ventricular dysfunction, exercise intolerance, or exercise-induced ischemia and may be considered for participation in high-intensity (classes II and IIIB or IIIC) sports (figure 2).

●Patients with severe systemic right ventricular (RV) dysfunction, severe RV outflow tract obstruction, severe AV valve regurgitation, or uncontrolled arrhythmias should be restricted from all competitive sports.

PREGNANCY — 

Successful pregnancy can be achieved in patients with ccTGA, but careful prepregnancy evaluation is required [41-43]. The examination includes assessment of cardiac rhythm, ventricular function without the use of angiotensin-converting enzyme inhibitor or angiotensin receptor blocker therapy (which is contraindicated during pregnancy), atrioventricular (AV) valvular function, associated lesions, and detection of any postoperative complications [39]. Patients with an indication for corrective intervention (eg, AV valve surgery) should undergo intervention prior to pregnancy. In general, patients with a systemic ventricular ejection fraction <40 percent and/or who have New York Heart Association functional class III or IV should be counseled to defer or avoid pregnancy since the added volume load of pregnancy is typically not well tolerated [39,41].

If pregnancy is undertaken, the patient should be monitored by a multidisciplinary health care team that includes an obstetrician and a cardiologist with expertise in congenital heart disease (CHD). Delivery should occur in a center with a health care team experienced in caring for patients with CHD and high-risk pregnancies.

Pregnancy outcomes in women with ccTGA were described in several small case series and registry studies involving a total of 82 patients and 146 pregnancies [42,44,45]. Maternal complications included heart failure (16 percent), thromboembolic events (4 percent, including a stroke in one patient), pregnancy-induced hypertension (4 percent), postpartum hemorrhage (4 percent), endocarditis (2 percent), and arrythmia (2 percent). There were no pregnancy-related maternal deaths. Approximately 80 percent of pregnancies resulted in live births; miscarriage or fetal death occurred in 15 percent. Complications among live-born infants included preterm birth (12 percent), small size for gestational age (17 percent), and low Apgar score (7 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 – Congenitally corrected transposition of the great arteries (ccTGA; also called L-looped TGA) is a rare and complex form of congenital heart disease (CHD) characterized by atrioventricular (AV) and ventriculoarterial discordance (figure 1). (See "Congenitally corrected (L-looped) transposition of the great arteries (ccTGA): Anatomy, clinical features, and diagnosis".)

●Surgical management – Surgical management of ccTGA in children has shifted from "physiologic approach" (wherein AV and ventriculoarterial discordance are maintained and surgical intervention is performed only to address associated cardiac defects) to "anatomic" repair, which makes the morphologic left ventricle (LV) the systemic ventricle and the morphologic right ventricle (RV) the pulmonary ventricle. The physiologic-based approach is associated with poor long-term outcome due to progressive RV failure. The rational for anatomic repair is that long-term outcome may be improved by having the morphologic LV serve as the systemic ventricle. (See 'Surgical management' above.)

•For pediatric patients with ccTGA associated with lesions that impose additional demand on the systemic RV (eg, clinically significant ventricular septal defect [VSD], LV outflow tract [LVOT] obstruction, and/or Ebstein-like malformation of the tricuspid valve), we suggest anatomic repair (Grade 2C). (See 'Our approach' above and 'Anatomic repair' above.)

•In patients with isolated ccTGA, the optimal approach is uncertain, and the choice of anatomic repair versus observation is individualized based on a patient-specific assessment of potential risks and benefits as well as the preference of the family. (See 'Our approach' above.)

•The two procedures for anatomic repair are the double switch operation and the Senning-Rastelli procedure. The choice between the two depends upon the presence of a large VSD and subpulmonary obstruction. (See 'Choice of procedure' above and 'Double switch operation' above and 'Senning-Rastelli procedure' above.)

●Surgical morbidity – Complications associated with anatomic correction in patients with ccTGA are primarily due to conduction abnormalities (ie, complete heart block and arrhythmias), LV dysfunction, and neo-aortic regurgitation. In addition, baffle-associated complications may also occur in patients who undergo a double switch operation. Patients who undergo surgical repair for ccTGA commonly require reintervention. (See 'Morbidity' above.)

●Follow-up care – All patients with ccTGA should have longitudinal follow-up care with a cardiologist experienced in managing CHD. Follow-up care includes a focused history and physical examination to detect signs and symptoms suggestive of systemic ventricular dysfunction and/or heart block as well as annual routine testing, including electrocardiography (ECG) and imaging by echocardiography. (See 'Follow-up care' above.)

●Pregnancy – Successful pregnancy can be achieved in patients with ccTGA, but careful prepregnancy evaluation is required. Patients with an indication for corrective intervention (eg, AV valve surgery) should undergo intervention prior to pregnancy. In general, patients with reduced ejection fraction and/or New York Heart Association functional class III or IV should be counseled to defer or avoid pregnancy since the added volume load of pregnancy is typically not well tolerated. (See 'Pregnancy' above.)