Double Outlet Right Ventricle Surgery

Double outlet right ventricle (DORV) refers to a heterogeneous series of associated cardiac anomalies that involve the right ventricular outflow tract in which both of the great arteries arise entirely or predominantly from the right ventricle. The anatomic dysmorphology of double outlet right ventricle can vary from that of tetralogy of Fallot (TOF) on one end of the spectrum to complete transposition of the great arteries (TGA) on the other end (see the image below).

In the United States, the incidence of double outlet right ventricle is an estimated 0.09 cases per 1000 live births. Double outlet right ventricle comprises about 1-1.5% of all congenital heart disease.[1]  No specific causal agent or predictive event has been identified.

The clinical presentation can vary from one of profound cyanosis to that of fulminant congestive heart failure. As a result, management and surgical repair of the defect are based on correcting the specific combination of anatomic defects with their radically different pathophysiologies.

Although hearts with atrioventricular discordance (ie, congenitally corrected TGA) or univentricular atrioventricular connections (ie, double inlet left ventricle) can be correctly grouped in this spectrum of anomalies, this article focuses on only those hearts with atrioventricular concordance and two functional ventricles.

History of the procedure

In 1793, Aberanthy described a heart with the origin of both great arteries from the right ventricle.[2, 3] The designation of “double outlet ventricle” was probably first reported by Braun et al in 1952.[4]  The first successful biventricular repair for this entity was reported by Sakakibara et al in 1967.[5]

The definition of a double outlet right ventricle (DORV) has been a point of controversy among professionals in the field of congenital heart surgery.[6] However, the Congenital Heart Surgery Nomenclature and Database Project defines double outlet right ventricle as a type of ventriculoarterial connection in which both great vessels arise either entirely or predominantly from the right ventricle.[7, 8]

In general, from a surgical perspective, defining the lesion as double outlet right ventricle is reasonable when more than 50% of both of the great arteries arise from the right ventricle. All of one vessel and most of the remaining vessel typically arise from the right ventricle. From the morphologic standpoint, some suggest that the absence of the fibrous continuity between the arterial and atrioventricular valves is a feature of double outlet right ventricle.

Before 1972, double outlet right ventricle (DORV) was defined as complete emergence of both great arteries from the right ventricle and no fibrous valvular continuity. The evaluation of this entity by Lev et al (1972) altered this classification; they proposed that aortomitral fibrous discontinuity was required.[9] In addition, Lev et al began to classify the group of anomalies in double outlet right ventricle by the ventriculoseptal defect (VSD) location (ie, the great vessel to which the VSD was anatomically adjacent).

Double outlet right ventricle is almost always associated with a VSD. Lev et al noted four possibilities of commitment of the double outlet right ventricle to the great arteries and termed them subaortic, subpulmonic, doubly committed, and noncommitted (or remote).[9] The location of the VSD has important implications on the physiologic manifestations of double outlet right ventricle and on surgical considerations.

The relative anatomic anomalies identified in the spectrum of double outlet right ventricle determine the clinical presentation and the surgical approach required for repair. Double outlet right ventricle can be described in terms of the relative position of the great arteries and the relative position of the VSD; the associated VSD is typically large and nonrestrictive.

Several associated cardiac anomalies are associated with double outlet right ventricle. Many of these affect the clinical presentation and the limits of the repair. Occurrence rates of associated cardiovascular anomalies are as follows[10] :

• Pulmonary stenosis: 21-47% (most commonly observed with subaortic type VSD)

• Atrial septal defect: 21-26%

• Patent ductus arteriosus: 16%

• Atrioventricular canal: 8%

• Subaortic stenosis: 3-30%

• Coarctation, hypoplastic arch, or interrupted aortic arch: 2-45%

• Mitral valve anomalies: 30%

Double outlet right ventricle (DORV) can be classified into four main categories on the basis of the location of the ventriculoseptal defect (VSD) in relation to great arteries:

• Double outlet right ventricle with subaortic VSD
• Double outlet right ventricle with subpulmonary VSD
• Double outlet right ventricle with doubly committed VSD
• Double outlet right ventricle with noncommitted VSD

Subaortic ventriculoseptal defect

Subaortic ventriculoseptal defect is the most common variant. The pathophysiology depends on the degree of pulmonary stenosis. With pulmonary stenosis, the pulmonary blood flow is decreased with variable degrees of cyanosis (Tetralogy of Fallot [TOF] type). In the absence of pulmonary stenosis, the pulmonary blood flow is increased, resulting in heart failure (VSD type).

Subpulmonary ventriculoseptal defect

In the subpulmonary ventriculoseptal defect variant of double outlet right ventricle, the pulmonary artery preferentially receives left ventricular (LV) oxygenated blood, and the desaturated blood from the right ventricle streams to the aorta (Transposition of the great arteries [TGA] type). The Taussig-Bing anomaly is a typical example of double outlet right ventricle with subpulmonary VSD. Aortic arch hypoplasia is a common association.

Doubly committed ventriculoseptal defect

The infundibular septum is absent in doubly committed ventriculoseptal defect, leaving both the aortic and pulmonary valves related to the VSD. Clinical features depend on the presence or absence of pulmonary stenosis.

Noncommitted ventriculoseptal defect

The noncommitted VSD is remote from the aortic and pulmonary valves. Most patients with noncommitted VSD undergo single ventricular palliative strategies.

The clinical presentation and management of double outlet right ventricle (DORV) is primarily dependent on its type (ie, ventricular septal defect [VSD], Fallot, transposition of great arteries [TGA], noncommitted [remote] VSD), as well as the presence of associated cardiac anomalies.[10]

Recognition and identification of clinically significant cardiac anomalies might first be based on a complete history of the patient's condition and its progression from parents. Elucidate feeding tolerance, weight gain, breathing problems, and a general failure to thrive.

Complete physical examination should include an evaluation of the cardiac valvular sounds, any murmurs and thrills, the point of maximal impact, and heaving of the chest wall. In addition, abnormal pulmonary signs (eg, rales, rhonchi, wheezing) and peripheral signs of cyanosis and capillary refill should be sought.

The severity or lack of pulmonary stenosis largely determines the spectrum of symptoms and the patient's age at the time of clinical presentation. In general, most patients present during the neonatal period. Patients with severe pulmonary stenosis have cyanosis, and those with uncontrolled pulmonary blood flow present with congestive heart failure.

Electrocardiographic findings are rarely diagnostic for double outlet right ventricle (DORV).

Common findings in a child with double outlet right ventricle include right ventricular hypertrophy, right axis deviation, and, occasionally, evidence of left ventricular hypertrophy.

Routine laboratory testing in patients with double outlet right ventricle includes the following:

• Complete blood cell (CBC) count
• Electrolyte levels
• Renal profile
• Hepatic function
• Coagulation profile
• Assessment of nutritional status, if indicated

​Echocardiography of the heart and great vessels

Echocardiography generally provides enough information for accurate and adequate diagnosis, and provides the needed information to plan the surgical approach in neonates and young infants.

Sanders et al reported that standard transthoracic echocardiography (TTE) was used to diagnose conotruncal malformation in 109 of 113 infants.[11] Of the 12 infants in whom double outlet right ventricle (DORV) was diagnosed and confirmed with angiography, 11 previously received a diagnosis based on subxiphoid two-dimensional echocardiography.

Echocardiography can be used to correctly identify the relative position of the great arteries, the degree of subsemilunar narrowing, the position of the ventricular septal defect (VSD), and the status of the mitral valve and left ventricle.

Cardiac angiography

Cardiac catheterization, once the criterion standard for confirming double outlet right ventricle, is now rarely required in the evaluation or preoperative planning of this cardiac disorder.

Angiography has several advantages, when indicated, such as the following:

• In the older child with long-standing disease, hemodynamic parameters can be directly measured.

• In the setting of possible aberrant coronary anatomy (3-5% of cases), the actual anatomic variation can be defined. This knowledge can affect surgical planning when Rastelli-type repair is contemplated.

• In the setting of pulmonary vascular anomalies, angiography can help in defining the main pulmonary branches, the pulmonary vascular tree, and the collateral vessels to the lungs.

Magnetic resonance imaging (MRI)

MRI has been used in the diagnosis of double outlet right ventricle, but it is not yet a routine or well-established diagnostic modality forthis condition. MRI is useful to obtain additional anatomic information, such as the relationship of both ventricles.

Chest radiography

Regardless of the end of the clinical spectrum (tetralogy of Fallot [TOF] or transposition of the great arteries [TGA]) at which double outlet right ventricle occurs, findings on anteroposterior and lateral chest radiography depend on the degree of pulmonary (or subpulmonary) stenosis.

In the setting of severe stenosis, the pulmonary parenchyma is relatively oligemic, whereas in the setting of minimal pulmonary stenosis (especially with a Taussig-Bing heart), findings are likely to be consistent with congestive heart failure. Either way, the chest image shows cardiomegaly.

Computed tomography (CT) scanning

Preoperative CT scanning is potentially useful for identifying coronary artery anatomy in children with TOF or Fallot type of double outlet right ventricle.[12]  A study that assessed the incidence and diagnostic accuracy of preoperative cardiac CT scanning for identifying detailed coronary artery anatomy in 318 children with TOF or Fallot type of double outlet right ventricle found a 95% concordance between cardiac CT scanning and surgical findings, and a 96.9% diagnostic accuracy for cardiac CT scanning.[12]

As discussed earlier, double outlet right ventricle (DORV) comprises a heterogeneous series of associated cardiac anomalies that involve the RV outflow tract in which both of the great arteries arise entirely or predominantly from the RV. The anatomic dysmorphology is variable, and there may be associated cardiac anomalies.

2020 Updated recommendations on the management of adult congenital heart disease by the European Society of Cardiology (ESC) include, but are not limited to, those summarized below.[13, 14]

Atrial septal defect (ASD) (native and residual)

ASD closure is recommended regardless of symptoms in those with evidence of right ventricular (RV) volume overload without pulmonary arterial hypertension (PAH) (no noninvasive signs of pulmonary arterial pressure [PAP] elevation or invasive proof of pulmonary vascular resistance [PVR] < 3 Wood units [WU] in case of such signs) or left ventricular (LV) disease.

Device closure is recommended as the method of choice for secundum ASD closure when technically suitable. In seniors not candidates for device closure, carefully weigh the surgical risk against the potential benefit of ASD closure.

In patients with noninvasive signs of PAP elevation, invasive PVR measurement is required. In patients with LV disease, perform balloon testing, and carefully weigh the benefit of eliminating left-to-right (LR) shunt against the potential negative impact of ASD closure on outcome due to an increase in filling pressure (when considering closure, fenestrated closure, and no closure).

ASD closure is not recommended in those with Eisenmenger physiology, those with PAH and PVR ≥5 WU despite targeted PAH treatment, or exercise desaturation.

Ventricular septal defect (VSD) (native and residual)

VSD closure is recommended regardless of symptoms in patients with evidence of LV volume overload without PAH (no noninvasive signs of PAP elevation or invasive proof of PVR < 3 WU in case of such signs).

VSD closure is not recommended in those with Eisenmenger physiology and those with severe PAH (PVR ≥5 WU) who present with exercise desaturation.

Atrioventricular septal defect (AVSD)

Surgical repair is not recommended in those with Eisenmenger physiology and patients with PAH (PVR ≥5 WU) who present with exercise desaturation.

Surgical closure performed by a congenital cardiac surgeon is recommended in patients with significant RV volume overload. Valve surgery, preferably AV valve repair, performed by a congenital cardiac surgeon is recommended in symptomatic patients with moderate to severe AV valve regurgitation.

In asymptomatic patients with severe left-sided AV valve regurgitation, valve surgery is recommended when LV end systolic diameter (ESD) is ≥45 mm and/or LV ejection fraction (EF) is ≤60% after ruling out other causes of LV dysfunction.

Patent ductus arteriosus (PDA)

In patients with evidence of LV volume overload and no PAH (no noninvasive signs of PAP elevation or invasive confirmation of PVR < 3 WU in case of such signs), PDA closure is recommended regardless of symptoms.

Device closure is recommended as the method of choice when technically suitable.

PDA closure is not recommended in patients with Eisenmenger physiology and patients with lower limb desaturation on exercise.

Subaortic stenosis

Surgery is recommended in symptomatic patients (spontaneous or on exercise test) with a mean Doppler gradient ≥40 mmHg or severe aortic regurgitation (AR).

Coarctation and recoarctation of the aorta

Repair of coarctation or recoarctation (surgically or catheter based) is indicated in hypertensive patients with an increased noninvasive gradient between the upper and lower limbs confirmed with invasive measurement (peak-to-peak ≥20 mmHg); catheter treatment (stenting) preferred when technically feasible.

Right ventricular outflow tract obstruction (RVOTO)

In valvular pulmonary stenosis, balloon valvuloplasty is the intervention of choice, if anatomically suitable.

As long as no valve replacement is required, RVOTO intervention at any level is recommended regardless of symptoms when the stenosis is severe (Doppler peak gradient >64 mmHg).

If surgical valve replacement is the only option, it is indicated in (1) symptomatic patients with severe stenosis; or (2) asymptomatic patients with severe stenosis in the presence of one or more of the following:

• Objective decrease in exercise capacity
• Falling right ventricular function and/or progression of tricuspid regurgitation to at least moderate
• RV systolic pressure over 80 mmHg
• Right-to-left (RL) shunting via an ASD or VSD

After repair of tetralogy of Fallot

Pulmonary valve replacement (PVRep) is recommended in symptomatic patients with severe pulmonary regurgitation (PR) and/or at least moderate RVOTO.

In those without a native outflow tract, catheter intervention (transcatheter pulmonary valve implantation [TPVI]) is preferred if anatomically feasible.

Transposition of the great arteries (TGA)

In symptomatic TGA patients after atrial switch operation with:

• Pulmonary venous atrium obstruction, surgical repair is recommended (catheter intervention is rarely possible)
• Baffle stenosis not amenable to catheter intervention, surgical repair is recommended
• Baffle leaks not amenable to catheter-based closure, surgical repair is recommended
• Baffle stenosis, stenting is recommended when technically feasible
• Baffle leaks and cyanosis at rest or during exercise, or with strong suspicion of paradoxical emboli, stenting (covered) or device closure is recommended when technically feasible

Pulmonary artery banding, as LV training with subsequent arterial switch procedure, is not recommended in TGA adults after atrial switch operation.

In TGA patients after atrial switch operation who have baffle leaks and symptoms due to LR shunt, stenting (covered) or device closure is recommended when technically feasible.

After arterial switch operation, for TGA patients with ischemia due to coronary artery stenosis, stenting or surgery (depending on substrate) is recommended.

For symptomatic patients with congenitally corrected TGA who have severe TR and preserved or mildly impaired systemic RV systolic function (EF >40%), TV replacement is indicated.

Right ventricular to pulmonary artery conduits

Symptomatic patients with RV systolic pressure >60 mmHg (may be lower in case of reduced flow) and/or severe PR should undergo intervention, with catheter intervention (TPVI) preferred if anatomically feasible.

Univentricular heart (UVH)

Adults with unoperated or palliated UVHs should undergo careful evaluation in specialized centers, including multimodality imaging as well as invasive work-up, to determine whether surgical or interventional procedures may provide benefit.

After Fontan operation

Sustained atrial arrhythmia with rapid atrioventricular conduction is a medical emergency; treat promptly with electrical cardioversion.

Anticoagulation is indicated in the presence, or with a history, of atrial thrombus, atrial arrhythmias, or thromboembolic events.

Counsel women with a Fontan circulation and any complication against pregnancy.

Cardiac catheterization is recommended at a low threshold in cases of unexplained edema, exercise deterioration, new-onset arrhythmia, cyanosis, and hemoptysis.

Medical management in the treatment of double outlet right ventricle (DORV) is based on the combination of anatomic lesions and the underlying physiology. A spectrum of presentations is possible with double outlet right ventricle, ranging from inadequate pulmonary blood flow with associated cyanosis to excessive pulmonary blood flow with congestive heart failure. However, double outlet right ventricle is a disorder that cannot spontaneously resolve, and the diagnosis alone is a sufficient indication for surgery.

In the setting of inadequate blood pulmonary blood flow, preserving ductal (ie, patent ductus arteriosus) blood flow is vital. An infusion of prostaglandin E (ie, alprostadil) is the standard of care until repair can take place. When the contrary clinical picture of congestive heart failure is present, careful diuresis, digoxin use, inotropic support, and pulmonary blood flow control by means of intubation and manipulation of blood gases may be indicated.

When double outlet right ventricle repair (DORV) is planned, several anatomic and physiologic factors are reviewed. The location of the ventriculoseptal defect (VSD) and its size are critical to the repair.[15, 16, 17]

Indications

Double outlet right ventricle (DORV) is a disorder that cannot spontaneously resolve, therefore the diagnosis alone is a sufficient indication for surgery. In general, palliative operations are performed only in patients who require short-term treatment, whereas noncardiac disease is managed (eg, sepsis) when anatomic features do not allow for definitive correction.

In the ideal case, repair of double outlet right ventricle is a corrective operation that leads to biventricular repair; thus, the left ventricle is connected to the aorta, and the right ventricle is connected to the main pulmonary artery. Palliative operations differ on the basis of the physiology of the subtype. In the case of excessive pulmonary blood flow, banding of the pulmonary artery can be used to palliate excessive pulmonary flow and protect the pulmonary vascular bed until definitive management can be undertaken. In the case of inadequate pulmonary blood flow, an aortopulmonary shunt, typically a Blalock-Taussig shunt, can be used to palliate inadequate pulmonary flow and promote growth for the pulmonary vascular bed and acceptable oxygenation until definitive management can be undertaken.

The staged, palliative bidirectional Glenn procedure has been used for patients with univentricular hearts or complex congenital heat disease, including double outlet right ventricle. In a retrospective (2015-2019) single-center experience of 115 patients who underwent this procedure, double outlet right ventricle was the anatomic diagnosis in 42.6% (49 patients) of patients.[18]  The investigators indicated that bidirectional Glenn procedure is effective at early and late stages in improving the efficacy of gas exchange and in reducing volume overload on the single ventricle. Postoperative morbidity and mortality risk was heightened by late age of presentation and poor preoperative nutrition.[18]

Contraindications

Absolute contraindications of double outlet right ventricle biventricular repair include significant left ventricular hypoplasia, and major overriding or straddling of atrioventricular valve. In those patients who are unsuitable for biventricular repair, single ventricle palliation would be indicated.

Use preoperative studies to accurately determine the surgically relevant features, including the following:

• Separation of the pulmonary valve from the tricuspid valve relative to the diameter of the aortic valve annulus

• Location of the ventriculoseptal defect (VSD), including the degree of involvement of the conal septum

• Chordal attachments to the conal septum, VSD ridge, and presence of straddling chordae

• Degree of subpulmonary stenosis and whether it is fixed or dynamic

• Degree of pulmonary valvar stenosis

• Coronary anatomy

• Relative size of the great vessels and their relationship

• The aortic arch and the presence of coarctation

Repair of double outlet right ventricle (DORV) with subaortic ventriculoseptal defect (VSD)

Repair of double outlet right ventricle with a subaortic VSD is accomplished by creating an intraventricular tunnel that channels left ventricular blood through the VSD to the aorta. This is facilitated by the use of a patch (eg, polytetrafluoroethylene [PTFE]) that corresponds to the circumference of the aorta.

After cardiopulmonary bypass with bicaval cannulation and cardioplegic arrest is established by routine means, the intracardiac anatomy is carefully inspected through a right atriotomy. The VSD is visualized through the tricuspid valve, and its relationship to the aorta is confirmed. If the VSD is suspected to be smaller than the aorta before or during surgery, the VSD is enlarged. The VSD is enlarged superiorly and anteriorly; thus, some of the infundibular septum is resected. The conduction tissue runs inferiorly and is avoided.

The patch is oriented along its longitudinal axis, corresponding to an imaginary line from the anterior-most portion of the aorta to the anterior-inferior limit of the VSD.

The VSD can be closed by using interrupted pledgetted sutures or a continuous-suture technique. If the intraventricular tunnel appears to be bulging into the right ventricular outflow tract (RVOT), the right ventriculotomy is closed with a patch (eg, autologous pericardium) to prevent RVOT obstruction (RVOTO).

In patients who have double outlet right ventricle with subaortic VSD and pulmonary stenosis, the general approach is similar to those with tetralogy of Fallot (TOF). Iti is important to identify the coronary arteries and mark the planned right ventriculotomy incision (if needed) before cardioplegic arrest is effected. The obstructive right ventricular muscle bundles are divided. The VSD is enlarged if restrictive.

Intraventricular tunnel repair of the VSD is similar to that used for patients who have double outlet right ventricle and subaortic VSD without pulmonary stenosis. The pulmonary valve, main pulmonary artery, and branch pulmonary artery are inspected and are patched as needed to eliminate obstruction. If an important coronary artery crosses the RVOT, a conduit may be added as an additional outflow path from the right ventricle. In patients with crossing coronary arteries, palliative surgery may result in two right ventricular outflow tracts: through the native pulmonary valve, and, if necessary, through the right ventricle to the pulmonary artery conduit.

Anatomic repair of double outlet right ventricle with subpulmonary VSD

The preferred surgical repair of double outlet right ventricle with subpulmonary VSD (ie, the Taussig-Bing heart) is anatomic repair (ie, the arterial switch operation). Because coarctation of the aorta is commonly observed in this situation, patients may have undergone coarctation repair with a pulmonary artery band, although single-stage repair of the coarctation and double outlet right ventricle can be accomplished. Atrial septectomy is performed if the atrial septum is restrictive. The subsequent procedure is a single-stage complete repair with VSD enlargement if restrictive, repair of the VSD to direct the left ventricular blood to the pulmonary artery, followed by an arterial switch procedure. When an aortic arch obstruction is also associated, it is repaired at the same time under hypothermic circulatory arrest.

Repair of double outlet right ventricle with doubly committed VSD

Surgical correction of double outlet right ventricle with a doubly committed VSD (an uncommon variant of this disorder) is performed in a fashion similar to that described above for double outlet right ventricle with subaortic VSD. The VSD, which is typically large, usually does not create difficulty in channeling left ventricular blood to the aorta with an intraventricular tunnel. Concurrent pulmonary stenosis or obstruction of the RVOT due to the tunnel may necessitate the creation of a right ventricle outflow patch or even a right ventricle–to–pulmonary artery conduit.

Repair of double outlet right ventricle with noncommitted VSD

Of the types of double outlet right ventricle, the most difficult to correct is the defect that requires repair of the noncommitted VSD.[19] Its correction is a high-risk procedure that often involves univentricular repair. However, biventricular repair of double outlet right ventricle with noncommitted VSD, based on specific anatomic features, is a challenging but achievable outcome.

The major feature of this anomaly is a persistent subaortic conus and a double infundibulum. The subaortic conus is in excess to essentially normal right ventricular structures. Therefore, this variation of double outlet right ventricle represents malposition of the aorta, with a normally positioned pulmonary artery and with the great vessels usually side by side. The VSD, usually perimembranous, often has inlet and/or trabecular extension and can be restrictive. Crucial to biventricular repair is the distance between the tricuspid and mitral annuli, because the aortic tunnel is constructed in this area.

Variations without pulmonary stenosis first require palliation with pulmonary artery banding. Severe subaortic obstruction, restrictive VSD, or aortic arch obstruction requires palliation with pulmonary artery banding. Variations with stenosis may be physiologically palliated, or a systemic-to-pulmonary shunt (eg, modified Blalock-Taussig shunt) may be required.

Contraindications to performing a biventricular repair include significant left ventricular hypoplasia, major overriding, or straddling of the atrioventricular valve.

With the use of combined atrial and ventricular approaches, an intraventricular tunnel that connects the VSD to the aorta is the operation of choice. A right vertical infundibulotomy is performed through the subaortic infundibulum, and the abnormal subaortic band between the subaortic conus and conal septum is resected. The diameter of the VSD is measured through the tricuspid valve and compared with that of the aorta, and the distance between the tricuspid annulus and the ostium infundibulum is measured—This last measurement should allow for a patch or tunnel that is at least the diameter of the aorta. Tricuspid chordal attachments blocking the channel are detached and reimplanted on the patch, and the VSD is enlarged anteriorly by avoiding the conduction tissue.

Two groups of investigators reported a mortality rate of approximately 10% for double outlet right ventricle noncommitted VSD, but the incidence of late subaortic stenosis is reasonably high.[20, 21]

When the VSD is distant, tunnel repair is associated with clinically significant subaortic stenosis in the early postoperative phase due to geometric errors in the construction of the tunnel and in the late postoperative phase due to fibrous obstruction.

When the VSD is situated in the inlet septum, Lacour-Gayet advocated using a tunnel to connect the VSD to the ostium infundibuli, followed by an arterial switch procedure.[22] He noted that the perimembranous VSD is close and requires a smaller tunnel. Also, the creation of a tunnel to the pulmonary artery does not depend on the pulmonary-tricuspid distance and is usually not affected by the presence of conal tricuspid chordae located above the tunnel. The subaortic band is resected, an infundibulotomy is created on the subpulmonary infundibulum, and the VSD is expanded. Then, an arterial switch procedure is performed as described above.[22] Lacour-Gayet reported excellent early results, with resolution of patients' New York Heart Association (NYHA) status.

A study by Li et al found an estimated overall 5-year survival rate of 87.1% following biventricular repair of double outlet right ventricle with noncommitted VSD.[23] The study included 75 patients (mean age 2.2 years) with the condition, with five types of biventricular repair performed. Surgery involved rerouting the VSD to either the aorta (40 patients) or the pulmonary artery (35 patients), with tunnel obstructions occurring in 10 patients who underwent the VSD-to-aorta procedure, versus none of the other patients, during the mean 4.1-year follow-up. The investigators also found that patients who underwent a concomitant tricuspid procedure had a significantly reduced likelihood of intracardiac obstruction, with no tricuspid regurgitation or stenosis developing.[23]

In 2021, Lu et al introduced a new, more simplified, and potentially more safe technique for biventricular repair of double outlet right ventricle with noncommitted VSD that involves the use of a 16- or 19-mm intraventricular polytetrafluoroethylene conduit to connect the VSD to the aorta in 31 patients older than 2 years (range: 2-23 y; median: 5.4 y).[6, 19, 24]  Median follow-up was 93 months (range: 8-14 months), during which no reoperations were necessary, one patient had significant left ventricular OTO; one patient died during hospitalization and a second died at 8 months postoperatively (6.5% overall mortality).[24]

An editorial comment by Jaggers and Stone about this study indicated a few potential advantages of this new technique, as follows[19] :

• "It avoids significant manipulation of the tricuspid valve" (eg, less distortion of the tricuspid subvalvular apparatus).
• "It results in a shorter distance of prosthetic, nonmuscular, akinetic pathway from the VSD to the aorta."
• "[It] avoids the necessary translocation of the coronary arteries, which are often abnormal. It also avoids the LeCompte maneuver, which can be tricky in patients with more side-by-side great vessels."

A limitation of this study is the older age of the patient cohort (typical age: < 1 y).[19] Lacour-Gayet raised two other, main study limitations[6] :

• "[T]he risk of impairing the tricuspid valve when suturing the proximal end of the conduit around the VSD in close contact with the conal papillary muscle"
• "[T]he risk of late left ventricular outflow tract obstruction with conduits sized 16 mm, which will likely require reoperation in adulthood" (The smallest acceptable size to avoid late subaortic obstruction is likely to be a 19-mm conduit.)

In a large series analyzing outcomes in patients with double outlet right ventricle (DORV) from 1980 to 2000, Brown et al reported a 56% 15-year overall survival (including the patients who underwent no surgical intervention).[25] The 15-year survival after repair for noncomplex double outlet right ventricle was 95%; it was 89% for Taussig-Bing anomaly.

In a study that sought to determine the risk factors of mortality and reoperation in 433 patients with double outlet right ventricle undergoing biventricular repair, according to anatomic characteristics and initial surgical strategy, three types of repair were performed: intraventricular baffle repair, intraventricular baffle repair with right ventricular outflow tract reconstruction, and intraventricular baffle repair with arterial switch operation.[26] The investigators found that initial surgical strategy did not influence the late outcomes, but patients with double outlet right ventricle with noncommitted ventricular septal defect (VSD) were at higher risk for reoperation and mortality.[26]

In another study that looked at data between 1993 and 2011 at two centers, 36 consecutive patients presenting with double outlet right ventricle or noncommitted VSD and two adequately sized ventricles underwent surgical repair.[27]  Of 24 patients who underwent anatomic repair via intraventricular baffle construction (median age: 10.5 months), the 10-year actuarial survival rate was 74.7 ± 5% and freedom from reoperation was 58 ± 5%. The remaining 12 patients underwent univentricular repair (group II), with a 10-year actuarial survival rate of 71 ± 7% and a 70 ± 7% rate of freedom from reoperation.[27]

Small left-sided structure, including left ventricle and mitral valve, structural abnormality of the mitral valve, and aortic arch obstruction, has been identified as a risk factor for death after repair.

Three-dimensional printed heart models are potentially useful in congenital heart surgery, In particular for demonstrating the association between intraventricular communications and great vessels, and in simulation for creating intracardiac pathways.[28]

Consensus surgical therapeutic strategies are available for noncomplex tetralogy-type double outlet right ventricle (DORV) and Taussig-Bing anomaly. Controversy remains as to whether or not the indication of biventricular repair should be extended to borderline anatomic subgroups, such as small left-sided structures (including mitral valve and left ventricle) or nonsubaortic ventricular septal defect (VSD). The subgroups of patients with these risk factors have suboptimal early and long-term outcomes. Furthermore, significant improvement of survival and quality of life in single-ventricle palliation and subsequent Fontan completion makes this issue debatable.