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Anomalies of Pulmonary Venous Connection and Cor Triatriatum

S. Adil Husain, John H. Calhoon
Anomalies of Pulmonary Venous Connection and Cor Triatriatum is a topic covered in the Adult and Pediatric Cardiac.

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Anomalies of Pulmonary Venous Connection

Nomenclature

As described in Chapter 2 of this Pediatric and Congenital Cardiac Section of this STS E-Book (Chapter 2: Nomenclature for Pediatric and Congenital Cardiac Care), both The International Paediatric and Congenital Cardiac Code (IPCCC) and the Eleventh Iteration of the International Classification of Diseases (ICD-11) provide the following hierarchy for congenital anomalies of pulmonary veins [1], [2], [3], [4], [5]:

Congenital anomaly of pulmonary vein

Anomalous pulmonary venous connection

Total anomalous pulmonary venous connection

Total anomalous pulmonary venous connection of the supracardiac type

Total anomalous pulmonary venous connection of the cardiac type

Total anomalous pulmonary venous connection of the infracardiac type

Total anomalous pulmonary venous connection of the mixed type

Partial anomalous pulmonary venous connection

Partial anomalous pulmonary venous connection of Scimitar type

Scimitar syndrome

Obstructed anomalous pulmonary venous pathway or connection

Congenital pulmonary venous stenosis or hypoplasia

Congenital atresia of pulmonary vein

As described in Chapter 2 of this Pediatric and Congenital Cardiac Section of this STS E-Book (Chapter 2: Nomenclature for Pediatric and Congenital Cardiac Care), both The International Paediatric and Congenital Cardiac Code (IPCCC) and the Eleventh Iteration of the International Classification of Diseases (ICD-11) provide the following definitions [1], [2], [3], [4], [5]:

ICD-11 Congenital Cardiac term

Definition

Synonyms

Abbreviations

Congenital anomaly of pulmonary vein

A congenital cardiovascular malformation in which there is an abnormality of the pulmonary veins.

Congenital malformation of pulmonary vein

Anomalous pulmonary venous connection

A congenital cardiovascular malformation in which one or more pulmonary vein(s) do(es) not connect normally to the morphologically left atrium.

APVC

Total anomalous pulmonary venous connection

A congenital cardiovascular malformation in which none of the pulmonary veins connect to the morphologically left atrium.

Totally anomalous pulmonary venous connection; Total anomalous pulmonary venous return

TAPVC, TAPVR, TAPVD

Total anomalous pulmonary venous connection of the supracardiac type

A congenital cardiovascular malformation with total anomalous pulmonary venous connection to the superior caval vein (superior vena cava) or one of its venous tributaries.

Total anomalous pulmonary venous connection Type 1

TAPVC Type I

Total anomalous pulmonary venous connection of the cardiac type

A congenital cardiovascular malformation with total anomalous pulmonary venous connection to the right atrium directly or to the coronary sinus or to both.

Total anomalous pulmonary venous connection Type 2; Total anomalous pulmonary venous connection, intracardiac

TAPVC Type 2

Total anomalous pulmonary venous connection of the infracardiac type

A congenital cardiovascular malformation with infradiaphragmatic total anomalous pulmonary venous connection.

Total anomalous pulmonary venous connection Type 3

TAPVC Type 3

Total anomalous pulmonary venous connection of the mixed type

A congenital cardiovascular malformation with total anomalous pulmonary venous connection at two or more levels (supracardiac, cardiac, or infracardiac).

Total anomalous pulmonary venous connection Type 4

TAPVC Type 4

Partial anomalous pulmonary venous connection

A congenital cardiovascular malformation in which one or more (but not all) of the pulmonary veins connect anomalously to the right atrium or to one or more of its venous tributaries and the remaining pulmonary veins connect to the left atrium.

Partially anomalous pulmonary venous connection; Partial anomalous pulmonary venous return

PAPVC. PAPVD, PAPVR

Partial anomalous pulmonary venous connection of Scimitar type

A congenital cardiovascular malformation with partial anomalous pulmonary venous connection in which some of the pulmonary veins (usually the right pulmonary veins) connect anomalously to the inferior caval vein (inferior vena cava) or to the right atrium at the insertion of the inferior vena cava.

Partial anomalous pulmonary venous return of Scimitar type

Scimitar syndrome

A congenital cardiopulmonary malformation with “partial anomalous pulmonary venous connection of Scimitar type” and one or more of the following: hypoplasia of the right lung with bronchial anomalies, dextrocardia, hypoplasia of the right pulmonary artery, lobar lung sequestration, and anomalous systemic arterial supply to the lower lobe of the right lung directly from the aorta or its main branches.

Pulmonary venolobar syndrome

Obstructed anomalous pulmonary venous pathway or connection

A congenital cardiovascular malformation in which the pathway of one or more anomalous pulmonary veins is blocked or impeded.

Obstructed anomalous pulmonary venous return

Congenital pulmonary venous stenosis or hypoplasia

A congenital cardiovascular malformation with a pathologic narrowing of one or more pulmonary veins including diffuse hypoplasia, long segment focal/tubular stenosis and/or discrete stenosis.

Congenital pulmonary vein stenosis and/or hypoplasia

Congenital atresia of pulmonary vein

A congenital cardiovascular malformation with atresia of one or more pulmonary veins.

Congenital pulmonary vein atresia

Pathologic Anatomy

Pulmonary venous drainage and its successful connection to the left atrium is the product of an embryologic process which is completed within the first 30 to 48 days of gestation. Four fully formed pulmonary veins open into the posterior aspect of the left atrial cavity and this connection is also associated with a correct axial orientation of the interatrial septum. Any deviation from this morphologic connection gives rise to an anomalous pulmonary venous connection.[6] Such an anomalous connection usually brings drainage of the pulmonary veins to the systemic venous side of circulation, creating a physiologic left to right shunt. The anomaly is classified as “total” anomalous pulmonary venous connection when none of the pulmonary veins morphologically connect to the left atrium and “partial” when some are connected normally and some anomalously.

Partial Anomalous Pulmonary Venous Connection (PAPVC)

Partial anomalous pulmonary venous connection is often associated with a sinus venosus atrial septal defect and most commonly with anomalous drainage of a portion of the R sided pulmonary venous return. However, PAPVC can also occur without presence of any atrial level communication. Drainage of R inferior pulmonary vein into IVC is often referred to as “Scimitar Syndrome” and is often associated with hypoplasia of the right lung (Figure 1).

Figure 1
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Forms of Partial Anomalous Pulmonary Venous Return (PAPVC).
(A) Sinus Venosus PAPV with connection from R pulmonary veins to SVC.[7]
(B) Right Pulmonary Vein to IVC in Scimitar Syndrome.[8]

Total Anomalous Pulmonary Venous Connection (TAPVC)

Total anomalous pulmonary venous connection is classified based upon the anatomic route the pulmonary venous blood takes anomalously to the systemic venous circulation (Figure 2).

  • Supra-cardiac: via ascending vertical vein and into innominate vein
  • Cardiac: via pulmonary venous confluence connection into R atrium / coronary sinus
  • Infra-cardiac: via descending vertical vein and into portal venous system
  • Mixed: varying forms of anomalous drainage for each lung
Figure 2
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Variants of total anomalous pulmonary venous connection (TAPVC).[9]
(A) Supracardiac: both right (RPV) and left (LPV) pulmonary veins join a common pulmonary venous confluence behind the heart, which drains via a vertical vein to the undersurface of the left innominate vein, and thence to the right atrium.
(B) Cardiac: the pulmonary venous confluence connects to the coronary sinus (CS), and thence to the right atrium via the coronary sinus ostium.
(C) Infracardiac: the pulmonary venous confluence drains inferiorly via a vertical vein to the portal vein (PV) or hepatic veins (HV) and thence to the right atrium.
(D) Mixed connections: left pulmonary veins drain to the left innominate vein (LIV), and right pulmonary veins to the coronary sinus in this example. IVC, inferior vena cava; SMV, superior mesenteric vein; SV, splenic vein.

Natural History

The clinical presentation of PAPVC may present as would any atrial level communication with evidence of a right heart volume overload. If such a lesion is associated with significant physiologic left to right shunt or elevated Qp:Qs, symptoms of excessive pulmonary blood flow and congestive heart failure will be present. On the other hand, the clinical presentation of TAPVC depends upon degree of obstruction to pulmonary venous drainage as well as the degree of obstruction to the compensatory right to left shunt through the atrial septum. As such, it may mimic obstructed TAPVC. Unobstructed TAPVC may thus also present with clinical findings similar to any child with a large left to right shunt and resultant tachypnea, failure to thrive, right ventricular volume overload pulmonary edema and congestive heart failure. However, in cases of obstructed TAPVC, presentation is more commonly associated with pulmonary venous and arterial hypertension, severe hypoxia and compensatory arterial desaturation with overall circulatory collapse.

Diagnostic Considerations

In cases of PAPVC, general physical examination findings will consist of a loud and continuously split S2 in addition to a systolic ejection murmur best auscultated over the pulmonary valve. This finding is generally due to increased pulmonary blood flow. Finding associated with obstructed TAPVC are more likely to be of cyanosis due to severe hypoxia. In addition, due to poor left sided filling and an overall low cardiac output state, evidence of poor perfusion with associated end organ dysfunction may be present such as cool extremities, poor pulses and a narrowed pulse pressure. Laboratory findings may reveal a metabolic acidosis, elevated lactate levels as well as biochemical markers of renal and hepatic dysfunction.

Diagnostic Studies

Chest Radiography

Cases of PAPVC are due to R sided pulmonary veins draining into the systemic venous circulation. An example of this is when drainage is into the IVC and subsequently into the right atrium. This scenario has been described in CXR findings as “Scimitar Syndrome” (Figure 3).

Figure 3
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CXR findings of Scimitar Syndrome – Turkish Sword.[10]

Unobstructed TAPVC may reveal pulmonary vascular congestion and a large cardiac silhouette. The “snowman” finding on chest radiograph is secondary to mediastinal and cardiac enlargement associated with prominent pulmonary arterial vasculature as well as the potential for a prominent SVC which is often found in cases of supracardiac TAPVC (Figure 4).

Figure 4
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Snowman sign in Supracardiac TAPVC.[11]

Chest radiographs of patients with obstructed TAPVC will commonly reveal severe pulmonary edema in the presence of a normally sized and shaped cardiac silhouette (Figure 5).

Figure 5
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Obstructed TAPVC with associated pulmonary venous congestion.[11]

Echocardiography

Two dimensional and doppler echocardiography is the primary diagnostic tool for most patients with anomalous pulmonary venous connections. Findings are commonly a combination of a distended right ventricle, some form of pulmonary vascular confluence with abnormal or absent drainage to the left atrium on doppler interrogation. Often, there is concomitant presence of an accessory common vein or dilated coronary sinus. In addition, echocardiographic evaluation may reveal turbulent flow in the right atrium with right to left atrial level shunt. In supracardiac TAPVC, with a left sided vertical vein draining to the innominate vein, the course of the vertical vein relative to the left pulmonary artery (LPA) is highly important. If coursing anterior to the LPA, obstruction is rare. However, if posterior to the LPA, compression (and thus obstruction) of the vein between the LPA and bronchus is essentially uniform.

CT Angiography (CTA) / Magnetic Resonance Angiography (MRA)

In non-emergency cases of TAPVC and PAPVC, contrast enhanced CT may be helpful to provide a complete anatomic diagnosis (Figure 6 and Figure 7). These modalities detail accurately the pulmonary venous anatomy and specifics regarding drainage patterns. From a functional standpoint, MRA may allow for quantitative determination of the amount of anomalous drainage and a resultant calculated Qp:Qs which may be more helpful in cases of PAPVC regarding delineation of operative indications. Additionally, MRA may also reveal pulmonary arterial and venous size as well as information regarding ventricular size and function.

PAPVC is often associated with drainage of the right superior and or middle lobe pulmonary veins into the SVC. This is often best delineated via use of CT angiography as an adjunct to echocardiography. More specifically, it allows for surgical planning and pre-operative counseling as to technical considerations for repair.[10]

Figure 6
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CTA findings of PAPVR with right sided pulmonary venous drainage into the SVC.[10]
Figure 7
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CT Angiography findings in Total Anomalous Pulmonary Venous Connection.[11]
(a) Supracardiac with ascending vertical vein in to SVC.
(b) Infracardiac with descending vertical vein into portal system below diaphragm.
(c) Mixed picture with R and L pulmonary veins taking independent course for drainage into R atrium.[10]

Pathophysiology Resulting From Anatomic Defect

In cases of normal circulation, oxygen depleted systemic venous blood is collected into the right atrium and traverses into the right ventricle to be ejected into the pulmonary vasculature. Upon becoming oxygenated, the blood then returns to the left atrium via pulmonary veins and subsequently to the left ventricle to be ejected out the aorta and to the systemic circulation.

In cases of TAPVC, oxygen-rich blood returns from the lungs to the R atrium or to a vein flowing into the R atrium. In this fashion, an adequate amount of oxygenated blood never gets to the systemic circulation. For child with TAPVC to survive, an atrial septal communication must exist to allow oxygenated blood to flow into the L side of the heart and thus out to the systemic circulation. The severity of this condition thus depends upon the degree of obstruction in the pathway of pulmonary venous blood into R atrium and then via an atrial level communication into the L atrium

Natural History Without Treatment

Natural history and clinical findings or progression without treatment is entirely dependent upon the anatomic form of anomalous pulmonary venous return. In cases of PAPVC, a thorough assessment of the anatomic and physiologic findings, to potentially include estimating Qp:Qs, may better allow a clinician to understand the natural history of progression without treatment. More specifically, non-surgical management may be appropriate in cases with small shunts and a single smaller anomalous vein draining systemically.

In cases of TAPVC, the degree of obstruction to venous return is directly correlative to the presenting clinical findings and likely natural history without treatment. In cases of obstructive TAPVC, the neonate will be profoundly cyanotic and in respiratory distress within hours or even minutes following birth. Inappropriate end organ perfusion and a metabolic acidosis may quickly develop. This is considered a surgical emergency. Infra-cardiac TAPVC is defined by many as being by definition, obstructed TAPVC. Initial medical management options include intubation, positive pressure ventilation with 100% oxygen along with correction of metabolic acidosis. Such interventions may be helpful, but not adequately address this emergent anatomic issue. Due to concerns of circulatory collapse, a delay in treatment or management may be fatal.

Non-obstructive TAPVC may present with a patient who will develop progressive volume overload of the right heart over time and this phenomena may be exacerbated with a drop in pulmonary vascular resistance over the first few weeks of life. Although the child may be treated into infancy with standard pulmonary decongestive measures, a lack of surgical intervention will lead to progressive RV failure.

History of Surgery for the Anatomic Lesion

Anatomic description and the evolution of surgical reparative techniques for anomalous pulmonary venous connections have evolved tremendously. The anatomic anomaly of TAPVC was first described by Wilson in 1798.[12] Reports of surgical repair and how they have developed over the past 6 decades provides a powerful example of the significant overall ability to treat complex congenital heart disease with successful interventions. In 1951, Muller described surgical palliation by anastomosing a common anomalous pulmonary venous “trunk” to the left atrial appendage.[13] Formal surgical correction for TAPVC was described by Lewis in 1956 using hypothermia and inflow occlusion.[14] The use of formal CPB in the correction of TAPVC was described by Burroughs and Kirkin in 1956.[15] The application of DHCA in the surgical correction of TAPVC was described by Barratt-Boyes in the early 1970s.[16] The “sutureless” technique for repair of pulmonary venous obstruction following repair of TAPVC was described by Lacour-Gayet in 1996 [17] and further described by Caldarone in 1998.[18]

Pre-Surgical Decision-Making

PAPVC

The timing of repair for PAPVC is a product of clinical and physiologic signs and symptoms. The presence of an atrial level communication, often times a sinus venosus atrial septal defect (ASD), may yield a more significant Qp:Qs and thus lead to an earlier approach at surgical repair. Adults who present with single vein PAPVC and no significant atrial level communication may not have concerning findings of right sided enlargement nor significant pulmonary over-circulation and thus may be followed without surgical intervention.

Non-Obstructed TAPVC

A focus on early primary surgical repair is universally supported, prior to cyanosis as well as right sided volume overload issues become more prominent. In a majority of cases, definitive repair is undertaken during the same hospitalization as time of diagnosis unless other significant comorbidities preclude such a strategy.

Obstructed TAPVC

Due to a lack of effective medical palliation, a neonate with obstructed TAPVC should be taken to the operating room immediately after confirmed echocardiographic diagnosis. As such, it is considered a surgical emergency. In extreme cases where such surgical support is not available, Extracorporeal Membrane Oxygenation (ECMO) may provide some form of clinical stability or end organ recovery prior to surgical intervention. If necessary, ECMO can also be employed as a posto-perative tool in the setting of low cardiac output syndrome to allow the left ventricle to become accustomed to being responsible for post reparative full cardiac output.

Surgical Management

PAPVC

Operative management and strategies employed for repair should be the product of a thorough pre and intra operative assessment of the anatomic variables associated with the partial anomalous pulmonary veins themselves, the entrance they have into the right atrium, atrial anatomy as well as the presence or absence of an atrial level communication.

Pulmonary Venous Anatomy: If the anomalous pulmonary veins from the right lung enter into the right atrium directly, or at the cavo-pulmonary junction, an intra cardiac baffling of the pulmonary venous blood through an atrial level communication may be feasible. If on the other hand, the entrance is into the SVC remote from the right atrium, two separate techniques may be considered.

The first approach is a “two patch technique” which preserves the SVC to R atrial connection (Figure 8). The initial atriotomy performed lateral and posterior to the SVC and R atrial junction provides exposure for an intra-cardiac patch to baffle pulmonary venous blood through an atrial level communication into the L atrium. Subsequently, a second patch is employed to augment the systemic venous channel from the SVC into the right atrium and is fashioned to avoid systemic venous obstruction secondary to the internal baffle. Attention is given to avoiding injury to the sino-atrial node.

Figure 8
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Two Patch Technique for PAPVC repair: First patch baffling anomalous pulmonary veins and closing the sinus venosus atrial septal defect. Inset: Second patch enlarging the SVC – R atrial junction.[19]

The second approach would require formal division of the SVC. This approach is often part of the Warden procedure which is described below (Figure 9). In addition, should the SVC require division, the atrial opening may be patch augmented to allow for a more unobstructed pathway for pulmonary venous blood flow into the atrium.

Atrial Anatomy: As mentioned previously, an atrial level communication may or may not be present in association with PAPVC. If not present, one must be surgically created to allow for a pathway to be constructed into the left atrium. In addition, in cases of a small atrial appendage, the Warden procedure may require patch augmentation to ensure the SVC to atrial appendage anastomosis is not the cause for future systemic venous obstruction.

The Warden Procedure has been described for repair of PAPVC involving the right upper and / or middle lobe pulmonary veins draining into the SVC with an associated sinus venosus ASD.[20] This procedure requires bicaval cannulation and complete cardiopulmonary bypass support. Caval snares may be placed and secured to completely exclude the heart.

Prior to arrest of the heart, the SVC may be divided carefully to ensure the transection is completed just proximal to the entry point of the anomalous pulmonary vein(s). The cardiac or distal side of the SVC may be over-sewn with a running Prolene suture. The aortic cross clamp is now placed and cardioplegia delivered. The right atrium is opened and the sinus venosus ASD identified. If an adequate atrial level communication is not present, one is created or enlarged. Patch material at the discretion of the surgeon is now employed to baffle the pulmonary venous blood across the ASD and towards the left atrium which in essence will concomitantly close the ASD. The proximal SVC is anastomosed to the right atrial appendage to allow for an adequate pathway for upper body systemic venous drainage. This suture line may be tied over a dilator to ensure there is no subsequent narrowing of this anastomosis. Such a narrowing resulting in SVC obstruction is cited as the most common long-term morbidity of this operative approach.

Figure 9
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Warden Procedure for PAPVR.[6]

Video description of the Warden Technique has been described.[21] Minimally invasive approaches to repair of PAPVR via bilateral anterolateral mini-thoracotomies have also been described.[22]

Several management strategies have been proposed for Scimitar Syndrome. A method of correction was described by Zubiate where patch material was employed to baffle flow from the anomalous vein in the IVC through the right atrium and into the ASD to redirect this pulmonary venous flow into the left atrium. The major drawback to this technique was the length of the baffle and concerns for IVC systemic drainage obstruction.[23] In addition, baffle thickening and or scarring may ultimately lead to pulmonary venous obstruction.

Schumaker described excising the anomalous pulmonary vein with a cuff of IVC and re-implanting it on the atrium directly and then creating an intracardiac baffle to the left atrium via the ASD. The IVC is then patched to avoid narrowing or obstruction.[24]

Gudjonsson and Brown described a technique where the 5th intercostal space is entered via a lateral thoracotomy. The right lung if freed of adhesions and the anomalous vein is dissected out to its thoracic course for mobilization. With the right pulmonary artery encircled and the patient heparinized, the anomalous vein is excised from the IVC and implanted directly into the left atrium, which is approached via a window created in the pericardium posterior to the phrenic nerve. An end to side anastomosis is created between the anomalous vein and the left atrium directly with control of the heart with a curved vascular clamp.[7]

TAPVC

Infracardiac TAPVC

Infracardiac TAPVC is the most common form of obstructed TAPVC and in this clinical scenario considered a surgical emergency. Patients thus present in the immediate neonatal period and are relatively unstable as has been described due to metabolic acidosis, significant hypoxia and circulatory collapse. In cases where there is no sign of pulmonary venous obstruction, a more elective approach to repair during the same hospitalization may be considered.

Repair of all types of TAPVC requires use of continuous cardiopulmonary bypass (CPB) and moderate systemic hypothermia. This is especially true for intracardiac TAPVC where pulmonary venous return to the right atrium is via the coronary sinus. In other cases of TAPVC, surgical intervention often requires better visualization of the pulmonary venous confluence and all pulmonary veins and the need to create a more blood less environment. As such, many surgeons advocate use of more aggressive hypothermia and even deep hypothermic circulatory arrest for neonatal repair of TAPVC.

Other technical considerations to keep in mind include ligation of a patent ductus arteriosus prior to or immediately following initiation of CPB. During the cooling phase, the heart may be elevated and rotated towards the right pleural space to expose the anomalous descending vertical vein often best located along the leftward posterior pericardial space. A Prolene suture may be placed at the apex of the heart to aid in gentle retraction. The posterior pericardium is opened and a vertical incision is made into the anomalous descending vertical vein associated with the pulmonary venous confluence. The vein as it extends into the abdomen is ligated with a silk suture. The heart may now be replaced into the mediastinum until full cooling is achieved.

The aorta may now be cross clamped and cardioplegia delivered for arrest and myocardial protection. Caval snares are secured around the SVC and IVC. The heart is once again elevated. A 6-0 Prolene suture may be placed into the left atrial appendage tip to again allow for gentle retraction. The left atrial appendage and left atrium are now opened and an anastomosis may be constructed between the left atrium and its appendage to the previously opened pulmonary venous confluence / descending vertical vein using a running 7-0 Prolene suture (Figure 10). The ASD may be closed prior to this anastomosis via the left atrium or after the anastomosis by opening up the right atrium following repositioning of the heart into the mediastinum.

Figure 10
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Repair of Infracardiac TAPVC:
(A) Schematic illustration of defect.[19]
(B) Schematic illustration of the correction of the defect.[19]
(C) Operative technique for correction of the defect.[19]

Thoughtfully prepared videos have been constructed to depict the correction of infracardiac TAPVC.[25]

Supra-Cardiac TAPVC

After achieving adequate hypothermia and arrest of the heart, a transverse incision is started near the base of the right atrial appendage and posterior to the atrioventricular groove. The incision is extended toward the interatrial groove and into the left atrium across the interatrial septum and ASD. The posterior wall of the left atrium is now incised transversely but not reaching the left atrial appendage (Figure 11).

The common pulmonary vein or confluence is identified and the pericardium overlying it is incised. The common vein is formally opened along a line similar to the incision in the posterior left atrial wall. 7-0 Prolene suture is employed to create an anastomosis of this posterior atrial wall to the pulmonary venous confluence. The atrial septum and the right atrial wall are sutured together to approximate the posterior edge of the right atriotomy. Patch material is now employed to enlarge the atrial septum and ensure unobstructed pulmonary venous return to the left atrium. The right atriotomy is now closed.

Figure 11
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Repair of Supracardiac TAPVC:
(A) Schematic illustration of defect.[19]
(B) Schematic illustration of correction of defect.[19]
(C) Biatrial incision for total correction of the defect.[19]

Another technique for management of supracardiac TAPVC is referred to as the “superior” approach. After arrest and delivery of cardioplegia, the aorta is retracted leftward and the dome of the left atrium is exposed. A tie is placed on the left atrial appendage for traction. The posterior pericardium just superior to the dome of the left atrium is opened and the pulmonary venous confluence is identified and opened in a longitudinal fashion (Figure 12).

A 7-0 Prolene suture is employed to create an anastomosis between the confluence and a matching incision within the dome of left atrium. The ASD is closed via a right atriotomy. In either technique, the ascending vertical vein is encircled with a heavy silk suture during cooling and then ligated during rewarming. Care should always be taken to ligate the vein as far away as possible from the pulmonary venous confluence. In addition, caution should be exercised in ensuring avoidance of unintended injury to the phrenic nerve during dissection or ligation of the vertical vein.

Figure 12
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Superior approach to supracardiac TAPVC via anastomosis of the posterior aspect of the left atrium to the pulmonary venous confluence.[19]

Cardiac TAPVC

Following arrest of the heart and delivery of cardioplegia, a generous right atriotomy is made and the edges appropriately retracted for exposure. The patent foramen ovale or ASD is identified as well as the coronary sinus. In most cases, the pulmonary veins drain directly into the coronary sinus and thus its orifice is generally somewhat enlarged.

The pulmonary venous blood is routed into the left atrium by enlarging the ASD and using a pericardial patch to baffle the anomalous blood into the left atrium (Figure 13). The atrial level defect may need to be enlarged by extending its inferior margin toward the inferior vena cava or common pulmonary vein orifice. Any incision to enlarge the coronary sinus orifice must be well away from the anterior margin of the coronary sinus to prevent damage to the atrioventricular node and the conduction system. Care should also be taken to ensure that in enlarging the ASD, the posterior wall of the left atrium is not inadvertently opened.

Figure 13
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Repair of intracardiac TAPVC.[19]
(A) schematic illustration of defect.
(B) schematic illustration of correction of defect.
(C) operative view of the extension of the ASD to incorporate the coronary sinus.
(D) correction of the anomaly by roofing the septal defect and rerouting pulmonary venous drainage into the left atrium.

Surgical management of Mixed forms of TAPVC can be the most challenging and have been described in video formats.[26]

Postoperative Complications

Arrhythmias

The incidence of post-operative dysrhythmias may be underreported. In particular, upwards of 29% of patients may show chronotropic impairment on exercise testing indicating sinus node dysfunction. Atrioventricular conduction delays and block are rare.[27] Long term follow-up of patients undergoing TAPVC with Holter studies may be of benefit to uncover supraventricular dysrhythmias as well as ventricular ectopy.[28] There does not appear to be any correlation between anatomic subtype, operative approach nor adequacy of repair with the incidence of dysrhythmias.

Pulmonary Hypertension

Restrictive pulmonary hypertension is a common post-operative physiologic challenge in patients following repair of TAPVC. The use of inhaled nitric oxide following separation from CPB as well as Sildenafil through and following extubation are examples of pulmonary vasodilator therapies employed to address this issue. In addition, patients may commonly be discharged to home with oxygen supplementation for longer term pulmonary vasodilator therapy.

Pulmonary Venous Stenosis

The most common post-operative complication and etiology for re-intervention is pulmonary venous stenosis.[29] Stenosis can be secondary to technical factors, anatomic or extrinsic compression or endocardial sclerosis. Risk factors for pulmonary venous stenosis have been described in various studies to include obstruction at time of presentation, small pulmonary venous confluence at time of repair, diffuse pulmonary stenosis and hypoplasia as well as mixed forms of TAPVC.

The sutureless technique of employing a pericardial in situ anastomosis to the re opened pulmonary venous confluence has shown promising results in regards to the operative re-intervention rates for pulmonary venous stenosis (Figure 14). Programs are now employing a sutureless technique to primary repair of TAPVC with the hopes of avoiding any manipulation or injury to pulmonary venous tissue or endothelium.[29]

Figure 14
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Sutureless technique for repair of Infracardiac TAPVC:
(A) Venous confluence is retro-pericardial. Left atrial incision is extended into appendage.
(B) Posterior pericardium is opened and descending vertical vein ligated. Pulmonary confluence is opened and incisions are extended into each pulmonary vein.
(C) Atrial edge is sutured to pericardium and in a fashion avoid direct suturing of pulmonary veins.

Outcomes and Complications

Early Outcomes

Early outcomes for repair of TAPVC in infancy, as reported prior to 1970, were associated with mortality rates of > 50%.[30] During the 1970s, with improvements in CPB techniques and myocardial protection, many centers reported mortality rates between 10-20%.[31] Larger single and multicenter series published in the early 2000s have reported three-year survival rates of 85% and an incidence of recurrent pulmonary venous stenosis in 15-20% of patients. Risk factors for death have been identified as obstruction at time of presentation, younger age at operation, associated cardiac lesions and post operative evidence of pulmonary venous stenosis.[32],[33] Patients with single ventricle disease and heterotaxy, who also have associated TAPVC, are also known to have worse outcomes.[34]

The largest single center series that looked at long term outcomes for surgical intervention for TAPVC had a study cohort of 377 patients and reported a 14-year survival of 65 +/- 6%. Significant (p< 0.01) risk factors for post repair death included cardiac connection type, earlier era of surgical intervention, younger age at repair, need for epinephrine post operatively and post operative pulmonary venous obstruction. In particular, cardiac connection type had a p value of 0.007 associated with mortality. In the study cohort, 9% of patients required re operation with mixed type of presentation being most common (p=0.04).[33]

The single center experience with perhaps the longest degree of follow up reported a study cohort of 214 patients with follow-up available for 96% of operative survivors at an average of 13 +/- 9 years (range 1 month – 42 years) after their operation. Survival at 10 and 20 years was 88% +/- 2.2%. Freedom from reoperation at 20 years was 86% +/- 3.2% and all survivors were asymptomatic at a mean of 13 +/9 years after the operation.[35]

Outcomes data harvested from larger multi institutional consortiums reveal in hospital mortality for patients undergoing surgical correction of TAPVC at 13%. This data is a product of 2,191 patients over a 25-year period of time within the Pediatric Cardiac Care Consortium (PCCC). Overall, 29% of patients within the study cohort presented with obstructed TAPVC and their operative mortality was 26%.[36]

Future Directions in Management

Although the typical management strategy for patients with TAPVC is surgical repair, primary trans-catheter palliation is being employed in certain circumstances. Stent placement into pulmonary venous anatomy at the site of obstruction has been described to preclude or delay surgery in cases of prematurity, low birth weight, multisystem organ dysfunction or multiple congenital anomalies. Stent placement is employed to relieve obstruction of pulmonary venous return, reduce pulmonary venous hypertension and allow for stabilization.[37] A majority of trans catheter approaches to the treatment of pulmonary venous disease has involved pulmonary venous obstruction following surgical repair of TAPVC. Results for such percutaneous interventions remain ill- defined and have not resulted in a paradigm shift in regards to standard of care surgical management strategies for TAPVC as have been outlined.

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Anomalies of Pulmonary Venous Connection

Nomenclature

As described in Chapter 2 of this Pediatric and Congenital Cardiac Section of this STS E-Book (Chapter 2: Nomenclature for Pediatric and Congenital Cardiac Care), both The International Paediatric and Congenital Cardiac Code (IPCCC) and the Eleventh Iteration of the International Classification of Diseases (ICD-11) provide the following hierarchy for congenital anomalies of pulmonary veins [1], [2], [3], [4], [5]:

Congenital anomaly of pulmonary vein

Anomalous pulmonary venous connection

Total anomalous pulmonary venous connection

Total anomalous pulmonary venous connection of the supracardiac type

Total anomalous pulmonary venous connection of the cardiac type

Total anomalous pulmonary venous connection of the infracardiac type

Total anomalous pulmonary venous connection of the mixed type

Partial anomalous pulmonary venous connection

Partial anomalous pulmonary venous connection of Scimitar type

Scimitar syndrome

Obstructed anomalous pulmonary venous pathway or connection

Congenital pulmonary venous stenosis or hypoplasia

Congenital atresia of pulmonary vein

As described in Chapter 2 of this Pediatric and Congenital Cardiac Section of this STS E-Book (Chapter 2: Nomenclature for Pediatric and Congenital Cardiac Care), both The International Paediatric and Congenital Cardiac Code (IPCCC) and the Eleventh Iteration of the International Classification of Diseases (ICD-11) provide the following definitions [1], [2], [3], [4], [5]:

ICD-11 Congenital Cardiac term

Definition

Synonyms

Abbreviations

Congenital anomaly of pulmonary vein

A congenital cardiovascular malformation in which there is an abnormality of the pulmonary veins.

Congenital malformation of pulmonary vein

Anomalous pulmonary venous connection

A congenital cardiovascular malformation in which one or more pulmonary vein(s) do(es) not connect normally to the morphologically left atrium.

APVC

Total anomalous pulmonary venous connection

A congenital cardiovascular malformation in which none of the pulmonary veins connect to the morphologically left atrium.

Totally anomalous pulmonary venous connection; Total anomalous pulmonary venous return

TAPVC, TAPVR, TAPVD

Total anomalous pulmonary venous connection of the supracardiac type

A congenital cardiovascular malformation with total anomalous pulmonary venous connection to the superior caval vein (superior vena cava) or one of its venous tributaries.

Total anomalous pulmonary venous connection Type 1

TAPVC Type I

Total anomalous pulmonary venous connection of the cardiac type

A congenital cardiovascular malformation with total anomalous pulmonary venous connection to the right atrium directly or to the coronary sinus or to both.

Total anomalous pulmonary venous connection Type 2; Total anomalous pulmonary venous connection, intracardiac

TAPVC Type 2

Total anomalous pulmonary venous connection of the infracardiac type

A congenital cardiovascular malformation with infradiaphragmatic total anomalous pulmonary venous connection.

Total anomalous pulmonary venous connection Type 3

TAPVC Type 3

Total anomalous pulmonary venous connection of the mixed type

A congenital cardiovascular malformation with total anomalous pulmonary venous connection at two or more levels (supracardiac, cardiac, or infracardiac).

Total anomalous pulmonary venous connection Type 4

TAPVC Type 4

Partial anomalous pulmonary venous connection

A congenital cardiovascular malformation in which one or more (but not all) of the pulmonary veins connect anomalously to the right atrium or to one or more of its venous tributaries and the remaining pulmonary veins connect to the left atrium.

Partially anomalous pulmonary venous connection; Partial anomalous pulmonary venous return

PAPVC. PAPVD, PAPVR

Partial anomalous pulmonary venous connection of Scimitar type

A congenital cardiovascular malformation with partial anomalous pulmonary venous connection in which some of the pulmonary veins (usually the right pulmonary veins) connect anomalously to the inferior caval vein (inferior vena cava) or to the right atrium at the insertion of the inferior vena cava.

Partial anomalous pulmonary venous return of Scimitar type

Scimitar syndrome

A congenital cardiopulmonary malformation with “partial anomalous pulmonary venous connection of Scimitar type” and one or more of the following: hypoplasia of the right lung with bronchial anomalies, dextrocardia, hypoplasia of the right pulmonary artery, lobar lung sequestration, and anomalous systemic arterial supply to the lower lobe of the right lung directly from the aorta or its main branches.

Pulmonary venolobar syndrome

Obstructed anomalous pulmonary venous pathway or connection

A congenital cardiovascular malformation in which the pathway of one or more anomalous pulmonary veins is blocked or impeded.

Obstructed anomalous pulmonary venous return

Congenital pulmonary venous stenosis or hypoplasia

A congenital cardiovascular malformation with a pathologic narrowing of one or more pulmonary veins including diffuse hypoplasia, long segment focal/tubular stenosis and/or discrete stenosis.

Congenital pulmonary vein stenosis and/or hypoplasia

Congenital atresia of pulmonary vein

A congenital cardiovascular malformation with atresia of one or more pulmonary veins.

Congenital pulmonary vein atresia

Pathologic Anatomy

Pulmonary venous drainage and its successful connection to the left atrium is the product of an embryologic process which is completed within the first 30 to 48 days of gestation. Four fully formed pulmonary veins open into the posterior aspect of the left atrial cavity and this connection is also associated with a correct axial orientation of the interatrial septum. Any deviation from this morphologic connection gives rise to an anomalous pulmonary venous connection.[6] Such an anomalous connection usually brings drainage of the pulmonary veins to the systemic venous side of circulation, creating a physiologic left to right shunt. The anomaly is classified as “total” anomalous pulmonary venous connection when none of the pulmonary veins morphologically connect to the left atrium and “partial” when some are connected normally and some anomalously.

Partial Anomalous Pulmonary Venous Connection (PAPVC)

Partial anomalous pulmonary venous connection is often associated with a sinus venosus atrial septal defect and most commonly with anomalous drainage of a portion of the R sided pulmonary venous return. However, PAPVC can also occur without presence of any atrial level communication. Drainage of R inferior pulmonary vein into IVC is often referred to as “Scimitar Syndrome” and is often associated with hypoplasia of the right lung (Figure 1).

Figure 1
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Forms of Partial Anomalous Pulmonary Venous Return (PAPVC).
(A) Sinus Venosus PAPV with connection from R pulmonary veins to SVC.[7]
(B) Right Pulmonary Vein to IVC in Scimitar Syndrome.[8]

Total Anomalous Pulmonary Venous Connection (TAPVC)

Total anomalous pulmonary venous connection is classified based upon the anatomic route the pulmonary venous blood takes anomalously to the systemic venous circulation (Figure 2).

  • Supra-cardiac: via ascending vertical vein and into innominate vein
  • Cardiac: via pulmonary venous confluence connection into R atrium / coronary sinus
  • Infra-cardiac: via descending vertical vein and into portal venous system
  • Mixed: varying forms of anomalous drainage for each lung
Figure 2
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Variants of total anomalous pulmonary venous connection (TAPVC).[9]
(A) Supracardiac: both right (RPV) and left (LPV) pulmonary veins join a common pulmonary venous confluence behind the heart, which drains via a vertical vein to the undersurface of the left innominate vein, and thence to the right atrium.
(B) Cardiac: the pulmonary venous confluence connects to the coronary sinus (CS), and thence to the right atrium via the coronary sinus ostium.
(C) Infracardiac: the pulmonary venous confluence drains inferiorly via a vertical vein to the portal vein (PV) or hepatic veins (HV) and thence to the right atrium.
(D) Mixed connections: left pulmonary veins drain to the left innominate vein (LIV), and right pulmonary veins to the coronary sinus in this example. IVC, inferior vena cava; SMV, superior mesenteric vein; SV, splenic vein.

Natural History

The clinical presentation of PAPVC may present as would any atrial level communication with evidence of a right heart volume overload. If such a lesion is associated with significant physiologic left to right shunt or elevated Qp:Qs, symptoms of excessive pulmonary blood flow and congestive heart failure will be present. On the other hand, the clinical presentation of TAPVC depends upon degree of obstruction to pulmonary venous drainage as well as the degree of obstruction to the compensatory right to left shunt through the atrial septum. As such, it may mimic obstructed TAPVC. Unobstructed TAPVC may thus also present with clinical findings similar to any child with a large left to right shunt and resultant tachypnea, failure to thrive, right ventricular volume overload pulmonary edema and congestive heart failure. However, in cases of obstructed TAPVC, presentation is more commonly associated with pulmonary venous and arterial hypertension, severe hypoxia and compensatory arterial desaturation with overall circulatory collapse.

Diagnostic Considerations

In cases of PAPVC, general physical examination findings will consist of a loud and continuously split S2 in addition to a systolic ejection murmur best auscultated over the pulmonary valve. This finding is generally due to increased pulmonary blood flow. Finding associated with obstructed TAPVC are more likely to be of cyanosis due to severe hypoxia. In addition, due to poor left sided filling and an overall low cardiac output state, evidence of poor perfusion with associated end organ dysfunction may be present such as cool extremities, poor pulses and a narrowed pulse pressure. Laboratory findings may reveal a metabolic acidosis, elevated lactate levels as well as biochemical markers of renal and hepatic dysfunction.

Diagnostic Studies

Chest Radiography

Cases of PAPVC are due to R sided pulmonary veins draining into the systemic venous circulation. An example of this is when drainage is into the IVC and subsequently into the right atrium. This scenario has been described in CXR findings as “Scimitar Syndrome” (Figure 3).

Figure 3
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CXR findings of Scimitar Syndrome – Turkish Sword.[10]

Unobstructed TAPVC may reveal pulmonary vascular congestion and a large cardiac silhouette. The “snowman” finding on chest radiograph is secondary to mediastinal and cardiac enlargement associated with prominent pulmonary arterial vasculature as well as the potential for a prominent SVC which is often found in cases of supracardiac TAPVC (Figure 4).

Figure 4
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Snowman sign in Supracardiac TAPVC.[11]

Chest radiographs of patients with obstructed TAPVC will commonly reveal severe pulmonary edema in the presence of a normally sized and shaped cardiac silhouette (Figure 5).

Figure 5
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Obstructed TAPVC with associated pulmonary venous congestion.[11]

Echocardiography

Two dimensional and doppler echocardiography is the primary diagnostic tool for most patients with anomalous pulmonary venous connections. Findings are commonly a combination of a distended right ventricle, some form of pulmonary vascular confluence with abnormal or absent drainage to the left atrium on doppler interrogation. Often, there is concomitant presence of an accessory common vein or dilated coronary sinus. In addition, echocardiographic evaluation may reveal turbulent flow in the right atrium with right to left atrial level shunt. In supracardiac TAPVC, with a left sided vertical vein draining to the innominate vein, the course of the vertical vein relative to the left pulmonary artery (LPA) is highly important. If coursing anterior to the LPA, obstruction is rare. However, if posterior to the LPA, compression (and thus obstruction) of the vein between the LPA and bronchus is essentially uniform.

CT Angiography (CTA) / Magnetic Resonance Angiography (MRA)

In non-emergency cases of TAPVC and PAPVC, contrast enhanced CT may be helpful to provide a complete anatomic diagnosis (Figure 6 and Figure 7). These modalities detail accurately the pulmonary venous anatomy and specifics regarding drainage patterns. From a functional standpoint, MRA may allow for quantitative determination of the amount of anomalous drainage and a resultant calculated Qp:Qs which may be more helpful in cases of PAPVC regarding delineation of operative indications. Additionally, MRA may also reveal pulmonary arterial and venous size as well as information regarding ventricular size and function.

PAPVC is often associated with drainage of the right superior and or middle lobe pulmonary veins into the SVC. This is often best delineated via use of CT angiography as an adjunct to echocardiography. More specifically, it allows for surgical planning and pre-operative counseling as to technical considerations for repair.[10]

Figure 6
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CTA findings of PAPVR with right sided pulmonary venous drainage into the SVC.[10]
Figure 7
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CT Angiography findings in Total Anomalous Pulmonary Venous Connection.[11]
(a) Supracardiac with ascending vertical vein in to SVC.
(b) Infracardiac with descending vertical vein into portal system below diaphragm.
(c) Mixed picture with R and L pulmonary veins taking independent course for drainage into R atrium.[10]

Pathophysiology Resulting From Anatomic Defect

In cases of normal circulation, oxygen depleted systemic venous blood is collected into the right atrium and traverses into the right ventricle to be ejected into the pulmonary vasculature. Upon becoming oxygenated, the blood then returns to the left atrium via pulmonary veins and subsequently to the left ventricle to be ejected out the aorta and to the systemic circulation.

In cases of TAPVC, oxygen-rich blood returns from the lungs to the R atrium or to a vein flowing into the R atrium. In this fashion, an adequate amount of oxygenated blood never gets to the systemic circulation. For child with TAPVC to survive, an atrial septal communication must exist to allow oxygenated blood to flow into the L side of the heart and thus out to the systemic circulation. The severity of this condition thus depends upon the degree of obstruction in the pathway of pulmonary venous blood into R atrium and then via an atrial level communication into the L atrium

Natural History Without Treatment

Natural history and clinical findings or progression without treatment is entirely dependent upon the anatomic form of anomalous pulmonary venous return. In cases of PAPVC, a thorough assessment of the anatomic and physiologic findings, to potentially include estimating Qp:Qs, may better allow a clinician to understand the natural history of progression without treatment. More specifically, non-surgical management may be appropriate in cases with small shunts and a single smaller anomalous vein draining systemically.

In cases of TAPVC, the degree of obstruction to venous return is directly correlative to the presenting clinical findings and likely natural history without treatment. In cases of obstructive TAPVC, the neonate will be profoundly cyanotic and in respiratory distress within hours or even minutes following birth. Inappropriate end organ perfusion and a metabolic acidosis may quickly develop. This is considered a surgical emergency. Infra-cardiac TAPVC is defined by many as being by definition, obstructed TAPVC. Initial medical management options include intubation, positive pressure ventilation with 100% oxygen along with correction of metabolic acidosis. Such interventions may be helpful, but not adequately address this emergent anatomic issue. Due to concerns of circulatory collapse, a delay in treatment or management may be fatal.

Non-obstructive TAPVC may present with a patient who will develop progressive volume overload of the right heart over time and this phenomena may be exacerbated with a drop in pulmonary vascular resistance over the first few weeks of life. Although the child may be treated into infancy with standard pulmonary decongestive measures, a lack of surgical intervention will lead to progressive RV failure.

History of Surgery for the Anatomic Lesion

Anatomic description and the evolution of surgical reparative techniques for anomalous pulmonary venous connections have evolved tremendously. The anatomic anomaly of TAPVC was first described by Wilson in 1798.[12] Reports of surgical repair and how they have developed over the past 6 decades provides a powerful example of the significant overall ability to treat complex congenital heart disease with successful interventions. In 1951, Muller described surgical palliation by anastomosing a common anomalous pulmonary venous “trunk” to the left atrial appendage.[13] Formal surgical correction for TAPVC was described by Lewis in 1956 using hypothermia and inflow occlusion.[14] The use of formal CPB in the correction of TAPVC was described by Burroughs and Kirkin in 1956.[15] The application of DHCA in the surgical correction of TAPVC was described by Barratt-Boyes in the early 1970s.[16] The “sutureless” technique for repair of pulmonary venous obstruction following repair of TAPVC was described by Lacour-Gayet in 1996 [17] and further described by Caldarone in 1998.[18]

Pre-Surgical Decision-Making

PAPVC

The timing of repair for PAPVC is a product of clinical and physiologic signs and symptoms. The presence of an atrial level communication, often times a sinus venosus atrial septal defect (ASD), may yield a more significant Qp:Qs and thus lead to an earlier approach at surgical repair. Adults who present with single vein PAPVC and no significant atrial level communication may not have concerning findings of right sided enlargement nor significant pulmonary over-circulation and thus may be followed without surgical intervention.

Non-Obstructed TAPVC

A focus on early primary surgical repair is universally supported, prior to cyanosis as well as right sided volume overload issues become more prominent. In a majority of cases, definitive repair is undertaken during the same hospitalization as time of diagnosis unless other significant comorbidities preclude such a strategy.

Obstructed TAPVC

Due to a lack of effective medical palliation, a neonate with obstructed TAPVC should be taken to the operating room immediately after confirmed echocardiographic diagnosis. As such, it is considered a surgical emergency. In extreme cases where such surgical support is not available, Extracorporeal Membrane Oxygenation (ECMO) may provide some form of clinical stability or end organ recovery prior to surgical intervention. If necessary, ECMO can also be employed as a posto-perative tool in the setting of low cardiac output syndrome to allow the left ventricle to become accustomed to being responsible for post reparative full cardiac output.

Surgical Management

PAPVC

Operative management and strategies employed for repair should be the product of a thorough pre and intra operative assessment of the anatomic variables associated with the partial anomalous pulmonary veins themselves, the entrance they have into the right atrium, atrial anatomy as well as the presence or absence of an atrial level communication.

Pulmonary Venous Anatomy: If the anomalous pulmonary veins from the right lung enter into the right atrium directly, or at the cavo-pulmonary junction, an intra cardiac baffling of the pulmonary venous blood through an atrial level communication may be feasible. If on the other hand, the entrance is into the SVC remote from the right atrium, two separate techniques may be considered.

The first approach is a “two patch technique” which preserves the SVC to R atrial connection (Figure 8). The initial atriotomy performed lateral and posterior to the SVC and R atrial junction provides exposure for an intra-cardiac patch to baffle pulmonary venous blood through an atrial level communication into the L atrium. Subsequently, a second patch is employed to augment the systemic venous channel from the SVC into the right atrium and is fashioned to avoid systemic venous obstruction secondary to the internal baffle. Attention is given to avoiding injury to the sino-atrial node.

Figure 8
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Two Patch Technique for PAPVC repair: First patch baffling anomalous pulmonary veins and closing the sinus venosus atrial septal defect. Inset: Second patch enlarging the SVC – R atrial junction.[19]

The second approach would require formal division of the SVC. This approach is often part of the Warden procedure which is described below (Figure 9). In addition, should the SVC require division, the atrial opening may be patch augmented to allow for a more unobstructed pathway for pulmonary venous blood flow into the atrium.

Atrial Anatomy: As mentioned previously, an atrial level communication may or may not be present in association with PAPVC. If not present, one must be surgically created to allow for a pathway to be constructed into the left atrium. In addition, in cases of a small atrial appendage, the Warden procedure may require patch augmentation to ensure the SVC to atrial appendage anastomosis is not the cause for future systemic venous obstruction.

The Warden Procedure has been described for repair of PAPVC involving the right upper and / or middle lobe pulmonary veins draining into the SVC with an associated sinus venosus ASD.[20] This procedure requires bicaval cannulation and complete cardiopulmonary bypass support. Caval snares may be placed and secured to completely exclude the heart.

Prior to arrest of the heart, the SVC may be divided carefully to ensure the transection is completed just proximal to the entry point of the anomalous pulmonary vein(s). The cardiac or distal side of the SVC may be over-sewn with a running Prolene suture. The aortic cross clamp is now placed and cardioplegia delivered. The right atrium is opened and the sinus venosus ASD identified. If an adequate atrial level communication is not present, one is created or enlarged. Patch material at the discretion of the surgeon is now employed to baffle the pulmonary venous blood across the ASD and towards the left atrium which in essence will concomitantly close the ASD. The proximal SVC is anastomosed to the right atrial appendage to allow for an adequate pathway for upper body systemic venous drainage. This suture line may be tied over a dilator to ensure there is no subsequent narrowing of this anastomosis. Such a narrowing resulting in SVC obstruction is cited as the most common long-term morbidity of this operative approach.

Figure 9
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Warden Procedure for PAPVR.[6]

Video description of the Warden Technique has been described.[21] Minimally invasive approaches to repair of PAPVR via bilateral anterolateral mini-thoracotomies have also been described.[22]

Several management strategies have been proposed for Scimitar Syndrome. A method of correction was described by Zubiate where patch material was employed to baffle flow from the anomalous vein in the IVC through the right atrium and into the ASD to redirect this pulmonary venous flow into the left atrium. The major drawback to this technique was the length of the baffle and concerns for IVC systemic drainage obstruction.[23] In addition, baffle thickening and or scarring may ultimately lead to pulmonary venous obstruction.

Schumaker described excising the anomalous pulmonary vein with a cuff of IVC and re-implanting it on the atrium directly and then creating an intracardiac baffle to the left atrium via the ASD. The IVC is then patched to avoid narrowing or obstruction.[24]

Gudjonsson and Brown described a technique where the 5th intercostal space is entered via a lateral thoracotomy. The right lung if freed of adhesions and the anomalous vein is dissected out to its thoracic course for mobilization. With the right pulmonary artery encircled and the patient heparinized, the anomalous vein is excised from the IVC and implanted directly into the left atrium, which is approached via a window created in the pericardium posterior to the phrenic nerve. An end to side anastomosis is created between the anomalous vein and the left atrium directly with control of the heart with a curved vascular clamp.[7]

TAPVC

Infracardiac TAPVC

Infracardiac TAPVC is the most common form of obstructed TAPVC and in this clinical scenario considered a surgical emergency. Patients thus present in the immediate neonatal period and are relatively unstable as has been described due to metabolic acidosis, significant hypoxia and circulatory collapse. In cases where there is no sign of pulmonary venous obstruction, a more elective approach to repair during the same hospitalization may be considered.

Repair of all types of TAPVC requires use of continuous cardiopulmonary bypass (CPB) and moderate systemic hypothermia. This is especially true for intracardiac TAPVC where pulmonary venous return to the right atrium is via the coronary sinus. In other cases of TAPVC, surgical intervention often requires better visualization of the pulmonary venous confluence and all pulmonary veins and the need to create a more blood less environment. As such, many surgeons advocate use of more aggressive hypothermia and even deep hypothermic circulatory arrest for neonatal repair of TAPVC.

Other technical considerations to keep in mind include ligation of a patent ductus arteriosus prior to or immediately following initiation of CPB. During the cooling phase, the heart may be elevated and rotated towards the right pleural space to expose the anomalous descending vertical vein often best located along the leftward posterior pericardial space. A Prolene suture may be placed at the apex of the heart to aid in gentle retraction. The posterior pericardium is opened and a vertical incision is made into the anomalous descending vertical vein associated with the pulmonary venous confluence. The vein as it extends into the abdomen is ligated with a silk suture. The heart may now be replaced into the mediastinum until full cooling is achieved.

The aorta may now be cross clamped and cardioplegia delivered for arrest and myocardial protection. Caval snares are secured around the SVC and IVC. The heart is once again elevated. A 6-0 Prolene suture may be placed into the left atrial appendage tip to again allow for gentle retraction. The left atrial appendage and left atrium are now opened and an anastomosis may be constructed between the left atrium and its appendage to the previously opened pulmonary venous confluence / descending vertical vein using a running 7-0 Prolene suture (Figure 10). The ASD may be closed prior to this anastomosis via the left atrium or after the anastomosis by opening up the right atrium following repositioning of the heart into the mediastinum.

Figure 10
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Repair of Infracardiac TAPVC:
(A) Schematic illustration of defect.[19]
(B) Schematic illustration of the correction of the defect.[19]
(C) Operative technique for correction of the defect.[19]

Thoughtfully prepared videos have been constructed to depict the correction of infracardiac TAPVC.[25]

Supra-Cardiac TAPVC

After achieving adequate hypothermia and arrest of the heart, a transverse incision is started near the base of the right atrial appendage and posterior to the atrioventricular groove. The incision is extended toward the interatrial groove and into the left atrium across the interatrial septum and ASD. The posterior wall of the left atrium is now incised transversely but not reaching the left atrial appendage (Figure 11).

The common pulmonary vein or confluence is identified and the pericardium overlying it is incised. The common vein is formally opened along a line similar to the incision in the posterior left atrial wall. 7-0 Prolene suture is employed to create an anastomosis of this posterior atrial wall to the pulmonary venous confluence. The atrial septum and the right atrial wall are sutured together to approximate the posterior edge of the right atriotomy. Patch material is now employed to enlarge the atrial septum and ensure unobstructed pulmonary venous return to the left atrium. The right atriotomy is now closed.

Figure 11
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Repair of Supracardiac TAPVC:
(A) Schematic illustration of defect.[19]
(B) Schematic illustration of correction of defect.[19]
(C) Biatrial incision for total correction of the defect.[19]

Another technique for management of supracardiac TAPVC is referred to as the “superior” approach. After arrest and delivery of cardioplegia, the aorta is retracted leftward and the dome of the left atrium is exposed. A tie is placed on the left atrial appendage for traction. The posterior pericardium just superior to the dome of the left atrium is opened and the pulmonary venous confluence is identified and opened in a longitudinal fashion (Figure 12).

A 7-0 Prolene suture is employed to create an anastomosis between the confluence and a matching incision within the dome of left atrium. The ASD is closed via a right atriotomy. In either technique, the ascending vertical vein is encircled with a heavy silk suture during cooling and then ligated during rewarming. Care should always be taken to ligate the vein as far away as possible from the pulmonary venous confluence. In addition, caution should be exercised in ensuring avoidance of unintended injury to the phrenic nerve during dissection or ligation of the vertical vein.

Figure 12
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Superior approach to supracardiac TAPVC via anastomosis of the posterior aspect of the left atrium to the pulmonary venous confluence.[19]

Cardiac TAPVC

Following arrest of the heart and delivery of cardioplegia, a generous right atriotomy is made and the edges appropriately retracted for exposure. The patent foramen ovale or ASD is identified as well as the coronary sinus. In most cases, the pulmonary veins drain directly into the coronary sinus and thus its orifice is generally somewhat enlarged.

The pulmonary venous blood is routed into the left atrium by enlarging the ASD and using a pericardial patch to baffle the anomalous blood into the left atrium (Figure 13). The atrial level defect may need to be enlarged by extending its inferior margin toward the inferior vena cava or common pulmonary vein orifice. Any incision to enlarge the coronary sinus orifice must be well away from the anterior margin of the coronary sinus to prevent damage to the atrioventricular node and the conduction system. Care should also be taken to ensure that in enlarging the ASD, the posterior wall of the left atrium is not inadvertently opened.

Figure 13
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Repair of intracardiac TAPVC.[19]
(A) schematic illustration of defect.
(B) schematic illustration of correction of defect.
(C) operative view of the extension of the ASD to incorporate the coronary sinus.
(D) correction of the anomaly by roofing the septal defect and rerouting pulmonary venous drainage into the left atrium.

Surgical management of Mixed forms of TAPVC can be the most challenging and have been described in video formats.[26]

Postoperative Complications

Arrhythmias

The incidence of post-operative dysrhythmias may be underreported. In particular, upwards of 29% of patients may show chronotropic impairment on exercise testing indicating sinus node dysfunction. Atrioventricular conduction delays and block are rare.[27] Long term follow-up of patients undergoing TAPVC with Holter studies may be of benefit to uncover supraventricular dysrhythmias as well as ventricular ectopy.[28] There does not appear to be any correlation between anatomic subtype, operative approach nor adequacy of repair with the incidence of dysrhythmias.

Pulmonary Hypertension

Restrictive pulmonary hypertension is a common post-operative physiologic challenge in patients following repair of TAPVC. The use of inhaled nitric oxide following separation from CPB as well as Sildenafil through and following extubation are examples of pulmonary vasodilator therapies employed to address this issue. In addition, patients may commonly be discharged to home with oxygen supplementation for longer term pulmonary vasodilator therapy.

Pulmonary Venous Stenosis

The most common post-operative complication and etiology for re-intervention is pulmonary venous stenosis.[29] Stenosis can be secondary to technical factors, anatomic or extrinsic compression or endocardial sclerosis. Risk factors for pulmonary venous stenosis have been described in various studies to include obstruction at time of presentation, small pulmonary venous confluence at time of repair, diffuse pulmonary stenosis and hypoplasia as well as mixed forms of TAPVC.

The sutureless technique of employing a pericardial in situ anastomosis to the re opened pulmonary venous confluence has shown promising results in regards to the operative re-intervention rates for pulmonary venous stenosis (Figure 14). Programs are now employing a sutureless technique to primary repair of TAPVC with the hopes of avoiding any manipulation or injury to pulmonary venous tissue or endothelium.[29]

Figure 14
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Sutureless technique for repair of Infracardiac TAPVC:
(A) Venous confluence is retro-pericardial. Left atrial incision is extended into appendage.
(B) Posterior pericardium is opened and descending vertical vein ligated. Pulmonary confluence is opened and incisions are extended into each pulmonary vein.
(C) Atrial edge is sutured to pericardium and in a fashion avoid direct suturing of pulmonary veins.

Outcomes and Complications

Early Outcomes

Early outcomes for repair of TAPVC in infancy, as reported prior to 1970, were associated with mortality rates of > 50%.[30] During the 1970s, with improvements in CPB techniques and myocardial protection, many centers reported mortality rates between 10-20%.[31] Larger single and multicenter series published in the early 2000s have reported three-year survival rates of 85% and an incidence of recurrent pulmonary venous stenosis in 15-20% of patients. Risk factors for death have been identified as obstruction at time of presentation, younger age at operation, associated cardiac lesions and post operative evidence of pulmonary venous stenosis.[32],[33] Patients with single ventricle disease and heterotaxy, who also have associated TAPVC, are also known to have worse outcomes.[34]

The largest single center series that looked at long term outcomes for surgical intervention for TAPVC had a study cohort of 377 patients and reported a 14-year survival of 65 +/- 6%. Significant (p< 0.01) risk factors for post repair death included cardiac connection type, earlier era of surgical intervention, younger age at repair, need for epinephrine post operatively and post operative pulmonary venous obstruction. In particular, cardiac connection type had a p value of 0.007 associated with mortality. In the study cohort, 9% of patients required re operation with mixed type of presentation being most common (p=0.04).[33]

The single center experience with perhaps the longest degree of follow up reported a study cohort of 214 patients with follow-up available for 96% of operative survivors at an average of 13 +/- 9 years (range 1 month – 42 years) after their operation. Survival at 10 and 20 years was 88% +/- 2.2%. Freedom from reoperation at 20 years was 86% +/- 3.2% and all survivors were asymptomatic at a mean of 13 +/9 years after the operation.[35]

Outcomes data harvested from larger multi institutional consortiums reveal in hospital mortality for patients undergoing surgical correction of TAPVC at 13%. This data is a product of 2,191 patients over a 25-year period of time within the Pediatric Cardiac Care Consortium (PCCC). Overall, 29% of patients within the study cohort presented with obstructed TAPVC and their operative mortality was 26%.[36]

Future Directions in Management

Although the typical management strategy for patients with TAPVC is surgical repair, primary trans-catheter palliation is being employed in certain circumstances. Stent placement into pulmonary venous anatomy at the site of obstruction has been described to preclude or delay surgery in cases of prematurity, low birth weight, multisystem organ dysfunction or multiple congenital anomalies. Stent placement is employed to relieve obstruction of pulmonary venous return, reduce pulmonary venous hypertension and allow for stabilization.[37] A majority of trans catheter approaches to the treatment of pulmonary venous disease has involved pulmonary venous obstruction following surgical repair of TAPVC. Results for such percutaneous interventions remain ill- defined and have not resulted in a paradigm shift in regards to standard of care surgical management strategies for TAPVC as have been outlined.

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Last updated: June 1, 2021