L-transposition of the great arteries (L-TGA): Management and outcome

INTRODUCTION — Levo- or L-looped transposition of the great arteries (L-TGA) is a rare form of congenital heart disease characterized by atrioventricular (AV) and ventriculoarterial discordance (figure 1). It is also commonly referred to as congenitally corrected TGA, double discordance, or ventricular inversion.

L-TGA usually does not present with cyanosis unless there are associated cardiac defects. Isolated L-TGA is "physiologically corrected" because systemic deoxygenated venous blood returns to the pulmonary circulation and oxygenated pulmonary venous blood returns to the systemic circulation. Patients with L-TGA are at increased risk for heart failure as adults due to progressive decline in systemic right ventricular (RV) function.

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

Dextro-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 from "physiologic" repair of the associated cardiac lesions while maintaining the congenitally corrected atrioventricular (AV) and ventriculoarterial discordance to an "anatomic" repair, which makes the morphologic left ventricle (LV) become the systemic pump and the morphologic right ventricle (RV) the pulmonary ventricle. Anatomic repair involves more complex surgical interventions and may require LV retraining. These two approaches (physiologic and anatomic repair), including their associated complications and outcomes, are discussed below. (See 'Physiologic repair' below and 'Anatomic repair' below.)

The optimal surgical approach for patients with L-TGA 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 L-TGA 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 L-TGA is associated with lesions that predispose to systemic heart failure (eg, clinically significant ventricular septal defect [VSD], LV outflow tract [LVOT] obstruction, and/or Ebstein-like malformation of the tricuspid valve):

•Patients with lesions predisposing to systemic heart failure – For pediatric patients with L-TGA associated with lesions that predispose to systemic heart failure (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 physiologic repair.

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 without lesions predisposing to systemic heart failure – In pediatric patients without associated lesions that predispose to systemic heart failure, the choice of anatomic repair versus medical management 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. Adults with isolated L-TGA who have not undergone anatomic repair are at risk for systemic heart failure, though the risk is lower in this population compared with patients who have additional associated lesions that increase the work of the systemic RV. (See "L-transposition of the great arteries (L-TGA): Anatomy, clinical features, and diagnosis", section on 'Isolated L-transposition of the great arteries'.)

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 L-TGA in adulthood usually present with heart failure, systemic tricuspid valve regurgitation, or arrhythmias. Patients with systemic tricuspid regurgitation should be referred for systemic AV valve repair before they develop morphologic RV failure or progressive dysfunction (systemic RV ejection fraction less than 40 percent). PA banding has been found to improve systemic AV valve regurgitation in select patients. 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.

Surgical procedures

Anatomic repair — The presence of associated lesions remains the major determinant regarding surgical repair of L-TGA. The poor late outcome associated with conventional repair has led to an alternative approach of anatomic correction to make the morphologic LV the systemic pump 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:

●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.

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

•Senning-Rastelli (SR) 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 dextro-TGA (D-TGA). (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 L-TGA for either of the following purposes (the first is more common):

●LV "training" – In L-TGA 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") [1-3]. Altering the LV and RV pressure ratio may also reduce the RV sphericity and improve the geometry of the RV prior to anatomic correction [4]. Several case series have shown that PA banding stabilizes systemic AV valve regurgitation and improves systemic ventricular function [4-6]. Typically, PA banding appears to be more successful in younger patients, and the younger the patient, the shorter interval required for training [5,7]. Patients older than 16 years of age appear to be unlikely to achieve sufficient LV function to proceed to anatomic correction [1].

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 [8]. 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 [9]. 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 [1].

The reported median time from PA banding to the DS procedure ranges from 2 to 14.5 months [3,7,9-11]. One center reported LV training using a more stringent threshold of 90 percent systemic pressure for the LV and typically preparing the ventricle for 9 to 12 months. Of their 26 patients with L-TGA, 92 percent met this threshold of successful LV retraining. Of the 19 patients who underwent a DS procedure in this cohort, survival was 100 percent at a mean follow-up of five years.

●Reducing 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 DS operation consists of an atrial switch procedure that creates an intra-atrial baffle (Mustard or Senning procedure) and an arterial switch operation (ASO). The intra-atrial baffle diverts the deoxygenated systemic venous return into the subpulmonary ventricle and oxygenated pulmonary venous return to the subsystemic ventricle. The ASO involves transection of both great arteries and then translocation of the vessels to the opposite root, similar to the ASO procedure performed for D-TGA requiring coronary artery transfer.

After a DS 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 [3,7,10,12-16]. 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 [3,7,10,12-16].

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 L-TGA that have a VSD and LVOT obstruction, the SR procedure is typically used. In this intervention, the intra-atrial baffle (Senning tunnel) is created and the VSD is closed by a baffle so that the blood from the LV is directed 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. The intermediate-term results show improved survival of this group compared with the patients undergoing a DS operation [12]. 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'.)

Long-term conduits become stenotic because they do not grow as the child grows. As a result, patients who undergo an SR procedure require serial conduit replacements [17].

Physiologic repair — In physiologic repair (also referred to as "conventional repair"), the congenitally corrected AV and ventriculoarterial discordance are maintained (ie, the morphologic RV remains the systemic ventricle). Surgical interventions focus on repairing the associated lesions present with L-TGA. As examples, a patient with a VSD would undergo VSD closure and a patient with LVOT obstruction would undergo surgical placement of an LV-to-PA conduit. Some affected patients may not undergo any surgical procedure initially if there are no associated lesions that require intervention. 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 approach to repair is associated with increased risk of systemic ventricular (RV) failure and tricuspid valve (systemic AV valve) regurgitation in adulthood. Surgical tricuspid valve replacement may be required in patients who develop significant tricuspid regurgitation. In a case series of 44 adults with isolated L-TGA who were not operated on in childhood and who were followed for a mean 12 years, 68 percent required tricuspid valve replacement after developing moderate to severe tricuspid regurgitation and ventricular dysfunction [18]. Four patients required cardiac transplantation. Preoperative systemic ventricular dysfunction (ie, ejection fraction [EF] <40 percent) predicted poor outcome (death or cardiac transplantation) [19].

Based on these findings, patients with L-TGA who do not undergo anatomic correction should have close monitoring of systemic ventricular function (morphologic RV) and tricuspid valvar function. Surgical interventions in these patients may include:

●Early tricuspid valve replacement (ideally performed before systemic ventricular failure develops).

●PA banding, which is an option for adults with L-TGA 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.

OUTCOME

After anatomic repair

Mortality

●Perioperative mortality – In a meta-analysis of 21 observational studies including 895 patients with L-TGA who underwent anatomic repair, the pooled operative mortality rate was 8 percent [20]. Early mortality is higher for the double switch (DS) operation compared with the Senning-Rastelli (SR) procedure [12,21].

●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 physiologic repair [15,21-24]. 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 [11,12,16,21,22,24]. 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), and relative frequency of the two anatomic repair procedures (DS and SR).

It is unclear whether long-term survival differs among patients who undergo DS versus SR. In one case series of 113 patients undergoing anatomic repair with either DS (n = 68) or SR (n = 45), actuarial survival at 10 years was 84 percent in the DS group and 77 percent in the SR group [12]. Similar findings were noted in another case series of 90 patients who underwent anatomic repair (18 patients had DS, 72 patient had SR), with reported 20-year survival rates of 83 and 76 percent, respectively [21]. Rates of freedom from reoperation and arrhythmia were slightly more favorable in the DS group compared with the SR group (freedom from reoperation 94 versus 78 percent; freedom from arrhythmia 79 versus 57 percent).

Morbidity — The complications associated with anatomic correction in patients with L-TGA 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 dextro-TGA (D-TGA) who undergo arterial switch operation (ASO) repair may also occur in patients with L-TGA who undergo DS operation.

Conduction abnormalities — Complete heart block and tachyarrhythmias occur in patients with L-TGA due to the abnormal configuration of conduction tissue. In addition, new-onset complete heart block and atrial arrhythmias are common complications postoperatively [10,12,13,15]. In the available case series, approximately 15 to 40 percent of patients required pacemaker implantation [12,15,16,25].

In a case series of 113 patients undergoing anatomic repair with either DS (n = 68) or SR (n = 45), 13 percent required preoperative permanent pacemaker implantation (all were in patients undergoing DS) and an additional 13 percent required postoperative pacemaker implantation (two-thirds were in patients undergoing DS and one-third in patients undergoing SR) [12]. In this cohort, tachyarrhythmias were noted preoperatively in four patients preoperatively and developed postoperatively in an additional four patients (three in the DS group and one in the SR 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 [5,8,12,15,26]. The underlying cause and risk factors for postoperative LV dysfunction remain uncertain.

In one case series, 16 of the 113 patients (14 percent) developed LV dysfunction postoperatively, all of whom were in the DS group [12]. Of these 16 patients, five were deemed high risk because they had heart failure prior to surgical intervention. Seven of the remaining 11 patients had pulmonary artery (PA) banding for LV training. There was no association between LV dysfunction and mild and moderate neo-aortic insufficiency, which was a common postoperative finding in patients who underwent DS operation. Another case series of 25 patients reported that PA banding before two years of age was associated with a lower risk of subsequent LV dysfunction [5].

In another case series 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 [26]. 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 [15,26].

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 ASO are at increased risk for neo-aortic regurgitation. In one series, 70 percent of patients after DS repair had at least mild aortic insufficiency at follow-up, including six patients with severe aortic insufficiency that required aortic valve replacement [12]. In a study that reported outcomes in 31 patients with L-TGA who underwent DS and 583 patients with D-TGA who underwent ASO, rates of aortic insufficiency and aortic valve replacement were higher in those with L-TGA compared with D-TGA [27].

PA banding is a risk factor for aortic root dilation and neo-aortic regurgitation in patients with D-TGA, and this has also been reported in patients undergoing LV training with PA banding in the L-TGA cohort [14,15,28].

Baffle-associated complications — There are limited reports of baffle-associated complications in patients with L-TGA undergoing anatomic repair; however, baffle-associated complications have been reported frequently in adult patients undergoing D-TGA surgical repair. It is reasonable to assume that similar complications may also occur in adult patients with L-TGA whose surgical repair includes creation of an intra-atrial baffle. These complications are described separately.

Reintervention — Surgical reintervention is common in patients who undergo either a DS operation or SR procedure [12,16,29]. 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 [12]. In the SR group (n = 45), 34 reinterventions were performed in 16 patients, including 14 right ventricle (RV)-PA conduit changes or ballooning; in the DS group (n = 68), 41 reinterventions were performed in 13 patients, including six aortic valve replacements, and surgical and catheter reinterventions of the Senning pathway 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) [29]. A revision of the Senning baffle was the most common indication for reoperation in this cohort (16 percent of reoperations).

After physiologic repair — The long-term outcome for individuals managed with physiologic repair is poor because of the progressive systemic RV dysfunction and heart failure.

In a case series from a single center of 123 patients with L-TGA who underwent conventional repair, survival at 5, 10, and 15 years was 75, 68, and 61 percent, respectively [30]. Risk factors associated with poor outcome included tricuspid valve replacement, preoperative RV dysfunction, complete heart block after surgery, subvalvular pulmonary stenosis, and Ebstein-like malformation of the tricuspid valve.

In another case series from a single center of 121 patients managed with physiologic repair (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 [31]. In multivariate analysis, complete AV canal defect and poor RV function were risk factors for mortality.

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

Several studies have shown that a substantial number of unoperated patients with L-TGA have compromised function and a reduction in quality of life. In a multicenter study of initially unoperated adult patients with L-TGA, only 60 percent of the patients with associated lesions and 70 percent of patients with isolated L-TGA classified themselves in Warnes-Somerville functional class I (defined as normal life, full-time work or school, can manage pregnancy) [32]. By the age of 45 years, two-thirds of patients with associated lesions and one-quarter of patients without additional cardiac defects had developed heart failure. (See "L-transposition of the great arteries (L-TGA): Anatomy, clinical features, and diagnosis", section on 'Natural history'.)

In a single-center study, the reported health status and quality of life were lower in adult patients with unoperated L-TGA compared with control patients with mild, hemodynamically insignificant defects [33]. Perceived health status declined with advancing age.

Adult patients with L-TGA have significantly reduced maximal oxygen uptake (30 to 50 percent) compared with healthy subjects [34]. These findings were a result of a combination of chronotropic incompetence as well as progressive systemic ventricular dysfunction.

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 [23].

In one study, self-reported quality-of-life and parent-reported quality-of-life scores were similar between 38 patients who underwent anatomic repair and 13 who were unoperated or treated with conventional repair [35]. However, the anatomic repair group self-reported a lower school function score compared with the conventional group. Lower quality-of-life scores after anatomic repair were associated with prolonged hospital stay and a need for a permanent pacemaker.

FOLLOW-UP CARE — Longitudinal follow-up care is required in all patients with L-TGA by a cardiologist with expertise in congenital heart disease. 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 [36]. 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 — Prophylactic antibiotics for endocarditis are recommended for patients who have surgical repairs that include the use of prosthetic material (eg, heart valve), patients who have had a prior episode of endocarditis, and patients with high-risk lesions for endocarditis (eg, unrepaired cyanotic heart disease or with a residual defect such as a patch margin ventricular septal defect [VSD]). (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 congenital heart disease, including L-TGA [37]. 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 L-TGA 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 L-TGA 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 women with L-TGA, but careful prepregnancy evaluation is required [38-40]. 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 [36]. In general, women with a systemic ventricular ejection fraction <40 percent and/or who have New York Heart Association functional class III or IV should be counseled against pregnancy since the added volume load of pregnancy is typically not well tolerated [36,38].

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

Pregnancy outcomes in women with L-TGA were described in two small series involving a total of 41 women and 105 pregnancies [39,41]. Approximately 75 percent of pregnancies resulted in live births. Complications included heart failure in four patients, cerebral vascular accident in one patient, and endocarditis in one patient. There were no pregnancy-related deaths.

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 – Levo- or left-transposition of the great arteries (L-TGA; also referred to as congenitally corrected TGA, double discordance, or ventricular inversion) is a rare and complex form of congenital heart disease characterized by atrioventricular (AV) and ventriculoarterial discordance (figure 1). (See "L-transposition of the great arteries (L-TGA): Anatomy, clinical features, and diagnosis".)

●Surgical management – Surgical management of L-TGA in children has shifted from "physiologic" repair (ie, repair of the associated lesions without addressing the AV and ventriculoarterial discordance) to "anatomic" repair, which makes the morphologic left ventricle (LV) the systemic pump and the morphologic right ventricle (RV) the pulmonary ventricle. Physiologic repair is associated with poor long-term outcome due to subsequent 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 L-TGA associated with lesions that predispose to systemic heart failure (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 L-TGA, anatomic repair is controversial and the choice of anatomic repair versus medical management 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 (DS) operation and the Senning-Rastelli (SR) procedure. The choice between the two is dependent on 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 L-TGA 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 DS operation. Surgical reintervention is common in patients who undergo either a DS operation or an SR procedure. (See 'Morbidity' above.)

●Follow-up care – Longitudinal follow-up care is required in all patients with L-TGA by a cardiologist with expertise in congenital heart disease. 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 women with L-TGA, but careful prepregnancy evaluation is required. In general, women with systemic ventricular ejection fraction <40 percent and/or New York Heart Association functional class III or IV should be counseled against pregnancy since the added volume load of pregnancy is typically not well tolerated. (See 'Pregnancy' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges David R Fulton, MD, who contributed to an earlier version of this topic review.