Procedure

Total anomalous pulmonary venous connection

Section of Cardiac Surgery, Division of Pediatric Cardiovascular Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA

^* Corresponding author: ^* F7830, Mott Children's Hospital, 1500 E. Medical Center Drive, Ann Arbor, MI 48109-0223, USA Tel.: +1-734-936 4980; fax: +1-734-763 7353.elbove{at}umich.edu

	Summary

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Total anomalous pulmonary venous connection (TAPVC) is subdivided into four types: supracardiac, cardiac, infracardiac, and mixed. The principle of operative repair is to establish an unobstructed communication between the pulmonary veins and the left atrium, interrupt the connections with the systemic venous circulation, and remove intracardiac shunting. The specific repair is dependent on the type of anomalous connection. Pulmonary venous obstruction is a significant and complex complication following TAPVC repair. The introduction of the sutureless pericardial marsupialization technique has greatly improved the outcome in this difficult patient group.

Key Words: Partial anomalous pulmonary venous connection • Pulmonary venous obstruction • Surgical repair of TAPVC • Total anomalous pulmonary venous connection

	Introduction

Top Summary Introduction Surgical technique Results Discussion References

 
Total anomalous pulmonary venous connection (TAPVC) is a relatively uncommon congenital defect representing approximately 2% of all congenital heart anomalies. TAPVC encompasses a group of anomalies in which the pulmonary veins connect directly to the systemic venous circulation via persistent splanchnic connections. This abnormality results from failed transfer, in the normal developmental sequence, of pulmonary venous drainage from the splanchnic plexus to the left atrium. The most common classification system was originally described by Darling et al. [1] and consists of four types: supracardiac, cardiac, infracardiac, and mixed. Partial anomalous pulmonary venous connection defines patients in whom some but not all venous drainage enters the left atrium, while the remaining veins connect to one or more persistent splanchnic veins.

TAPVC can also be classified by the presence of obstruction. Impingement from surrounding structures or inadequate caliber of the draining pulmonary vein(s) can result in varying degrees of obstruction. Obstruction in supracardiac TAPVC can occur by compression of the ascending vertical vein between the left main stem bronchus and left pulmonary artery or by narrowing at the insertion of the vertical vein into the innominate vein. Obstruction is always present in the infracardiac type because the pulmonary venous blood must pass through the sinusoids of the liver. Obstruction is uncommon in the cardiac type.

Supracardiac TAPVC (Schematic 1) occurs in approximately 45% of patients. The common pulmonary vein drains superiorly into the innominate vein, superior vena cava, or azygous vein via an ascending vertical vein. Cardiac TAPVC (Schematic 2) occurs in approximately 25% of patients. The pulmonary venous confluence drains into the coronary sinus or, on rare occasions, individual pulmonary veins will connect directly into the right atrium. Infracardiac TAPVC (Schematic 3) occurs in approximately 25% of patients. The pulmonary venous confluence drains into a descending vertical vein through the diaphragm into the portal vein or ductus venosus. Finally, a mixed type of TAPVC occurs in approximately 5% of patients and can involve any or all components of the previous three types.

View larger version (82K): [in this window] [in a new window]   Schematic 1 Supracardiac TAPVC: The common pulmonary vein drains superiorly into the innominate vein or superior vena cava via an ascending vertical vein. Reprinted with permission from Ref. [12].

View larger version (99K): [in this window] [in a new window]   Schematic 2 Cardiac TAPVC: The common pulmonary vein drains into the coronary sinus or, on rare occasions, individual pulmonary veins will connect directly into the right atrium. Reprinted with permission from Ref. [12].

View larger version (88K): [in this window] [in a new window]   Schematic 3 Infracardiac TAPVC: The common pulmonary vein drains through the diaphragm into the portal vein or ductus venosus. Reprinted with permission from Ref. [12].

The diagnosis can be made with echocardiographic identification of the anomalous connection of the pulmonary venous confluence to the systemic venous system (Videos 1,2,3,4). The atrial septal defect and other associated anomalies can be delineated. Cardiac catheterization is rarely necessary unless accurate measurement of pulmonary vascular resistance is needed.

Click on image to view video Video 1 Transthoracic ECHO of supracardiac TAPVC demonstrating the pulmonary venous confluence entering the ascending vertical vein which drains into the innominate vein. (Innom V=innominate vein, SVC=superior vena cava, VV=vertical vein, PV confl=pulmonary venous confluence.)

Click on image to view video Video 2 Transthoracic ECHO of cardiac TAPVC demonstrating the pulmonary venous confluence draining into a dilated coronary sinus. (PV=pulmonary veins, ASD=atrial septal defect, CS=coronary sinus.)

Click on image to view video Video 3 Transthoracic ECHO of infracardiac TAPVC demonstrating the pulmonary venous confluence behind the left atrium with the descending vertical vein. (PA=pulmonary artery, LA=left atrium, PV confluence=pulmonary venous confluence, VV=vertical vein.)

Click on image to view video Video 4 Transthoracic ECHO of infracardiac TAPVC demonstrating subdiaphragmatic drainage of the descending vertical vein into the inferior vena cava. (VV=vertical vein, Hep V=hepatic veins.)

	Surgical technique

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The principle of operative repair is to establish an unobstructed communication between the pulmonary venous confluence and the left atrium, interrupt the connections with the systemic venous circulation, and close the atrial septal defect. The specific repair is dependent on the type of anomalous connection.

The patient undergoes standard cardiac anesthesia. Optimization of ventilator settings to reduce pulmonary hypertension is employed, including hyperventilation and 100% oxygen. The chest is opened via a median sternotomy. The presence of thymic tissue should be noted. Standard cardiopulmonary bypass (CPB) can be established with an arterial cannula in the ascending aorta and a single venous cannula in the right atrial appendage. The ductus arteriosus should be identified and ligated after establishing CPB. If a period of deep hypothermic circulatory arrest is to be employed, the patient is cooled for a minimum of 20 min to a core temperature of 18°C. A dose of cold blood cardioplegia is administered (30 ml/kg) prior to initiating circulatory arrest. Low flow cardiopulmonary bypass with deep hypothermia may also be used, depending on exposure. Essential to successful repair is the proper identification of all four pulmonary veins and their anomalous connection prior to repair. Although preoperative studies are highly accurate, a mixed type of connection may be missed.

Supracardiac TAPVC
For supracardiac connections, the optimal approach is to retract the ascending aorta and superior vena cava laterally to expose the pulmonary venous confluence. This approach provides excellent exposure without distortion of the heart or venous structures. The vertical vein can be identified and ligated (just prior to opening the confluence) outside the pericardium at the level of the innominate vein. Care should be taken to avoid the phrenic nerve, which travels along the lateral aspect of the vertical vein. The entry of the left upper pulmonary vein should also be carefully identified to avoid inadvertent ligation. A transverse incision is made in the pulmonary venous confluence and a parallel incision is placed in the dome of the left atrium beginning at the base of the left atrial appendage. The common pulmonary vein is then anastomosed to the left atrium taking care to construct an unrestrictive connection (Schematic 4A, B). The anastomosis may be performed with either continuous monofilament absorbable or polypropylene suture. A right atriotomy is made to close the atrial septal defect. Use of a prosthetic or pericardial patch is often required. Enlargement of the left atrium is not needed.

View larger version (62K): [in this window] [in a new window]   Schematic 4 Supracardiac TAPVC: (A) The vertical vein is ligated and a longitudinal incision is made in the pulmonary venous confluence and the dome of the left atrium. The confluence and atrium are anastomosed; (B) depiction of completed repair with the atrial septal defect closed; (C) transverse right atriotomy extended into the left atrium with a parallel incision in the pulmonary venous confluence. The confluence and left atrium are anastomosed, the atrial septal defect is closed with a patch, and the right atriotomy is closed. Reprinted with permission from Ref. [12].

Cardiac TAPVC
The repair of cardiac TAPVC can be performed with bicaval cannulation and moderate hypothermia (28–32°C) with the use of a vent or a cardiotomy sucker to capture the pulmonary venous return. A right atriotomy is performed with identification of the atrial septal defect and the orifice of the coronary sinus (Schematic 5A). The roof of the coronary sinus is excised into the left atrium (Schematic 5B). A patch of pericardium or prosthetic material is then placed to close the enlarged atrial septal defect, effectively channeling the pulmonary venous return into the left atrium (Schematic 5C). The conduction system travels in proximity to the coronary sinus and care needs to be taken while suturing the patch in this area to avoid heart block (Video 5).

View larger version (74K): [in this window] [in a new window]   Schematic 5 Cardiac TAPVC: (A) The pulmonary confluence connects into a dilated coronary sinus with a small secundum atrial septal defect; (B) the roof of the coronary sinus is incised into the left atrium and the atrial septal defect is enlarged to communicate with the unroofed coronary sinus; (C) patch closure of the enlarged atrial septal defect channeling the pulmonary venous return and coronary sinus return into the left atrium. Reprinted with permission from Ref. [12].

Click on image to view video Video 5 Repair of Cardiac TAPVC.

View larger version (70K): [in this window] [in a new window]   Schematic 6 Infracardiac TAPVC: (A) Ligation of the descending vertical vein at the level of the diaphragm, incision of the posterior wall of the left atrium as well the central pulmonary venous confluence; (B) the pulmonary venous confluence and left atrium are anastomosed. Reprinted with permission from Ref. [12].

Recurrent pulmonary venous obstruction
The approach to recurrent pulmonary venous obstruction is dependent upon the level of obstruction. Obstruction can develop at the anastomosis or within the individual pulmonary veins. The latter may initially present as an anastomotic constriction, as the true extent of obstruction is not always apparent at first. Isolated narrowing of the anastomosis between the common pulmonary vein and left atrium often can be repaired with revision or patch augmentation of the anastomosis. Many efforts have been employed to prevent narrowing at the suture line including the use of absorbable sutures or interrupted sutures without significant differences in the incidence of stenosis.

Obstruction of the individual pulmonary venous ostia is the greater challenge. Although the obstruction may initially appear to be limited to the ostium, progressive narrowing along the entire length of the vein into the hilum of the lung will occur with time. The obstruction usually develops within the first several months following initial repair. Repair of this lesion is technically challenging and recurrent early obstruction is common. A new approach to recurrent pulmonary vein stenosis following repair of TAPVC was reported by Lacour-Gayet et al. [2]. This approach employs a sutureless technique utilizing in situ pericardium to create a neo-atrium. The theory behind this repair is based on the concept that pulmonary venous obstruction results from inflammation induced locally by suture placement. Repair involves wide unroofing of the narrowed portion of each involved pulmonary vein from the left atrial anastomosis to the hilum (Schematic 7A, B). A wide flap of pericardium is then elevated with care taken to avoid disruption of posterior adhesions and injury to the phrenic nerve. This flap of pericardium is rotated over the unroofed pulmonary veins and sutured to the left atrial wall away from the venous ostia (Schematic 7C). A large neo-atrium is then created into which pulmonary venous return can drain. This technique can be used effectively for both right and left sided pulmonary venous obstruction.

View larger version (59K): [in this window] [in a new window]   Schematic 7 Recurrent obstructed TAPVC: (A) A wide flap of pericardium is mobilized, the obstructed pulmonary veins are visualized from the left atrium into the hilum of the lung; (B) recurrent obstructed TAPVC: The obstructed pulmonary veins are widely unroofed; (C) The mobilized flap of pericardium is rotated over the unroofed pulmonary veins and sutured to the left atrial wall away from the venous ostia. Reprinted with permission from Ref. [12].

	Results

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Recurrent venous obstruction develops in 5–15% of patients [4]. Results following balloon angioplasty and/or stent insertion have been disappointing and recurrent stenoses are the rule. Individual patch angioplasty of the ostia has also been utilized with poor long-term results. Lung transplantation has been considered in severe cases of extensive, bilateral disease. The mortality associated with reoperation for obstruction can be up to 50% when bilateral stenoses are present [5]. The use of the sutureless technique for recurrent pulmonary vein obstruction as described above has demonstrated improved survival and decreased recurrence [4, 6].

	Discussion

Top Summary Introduction Surgical technique Results Discussion References

 
TAPVC is an uncommon congenital heart lesion and the experience of most individual institutions is relatively small. Some recent published results are shown in Table 1 (includes only patients with two ventricle anatomy). Preoperative pulmonary venous obstruction has been neutralized as a risk factor for late survival or recurrent pulmonary venous obstruction [11]. Some studies have shown an increased risk of recurrent obstruction in infracardiac TAPVC as well as TAPVC associated with single ventricle, mixed venous connections, and right atrial isomerism [4, 10]. TAPVC in association with single ventricle anatomy constitutes a highly complex patient population with high (>30%) mortality and morbidity [4, 6, 8]. Patients who present with recurrent obstruction are at even higher risk for early and late mortality as well as progressive obstruction [8]. The introduction of the sutureless pericardial technique has significantly improved survival and decreased the rate of recurrent obstruction (Table 2).

	References

Top Summary Introduction Surgical technique Results Discussion References

1. Craig JM, Darling RC, Rothney WB. Total pulmonary venous drainage into the right side of the heart; report of 17 autopsied cases not associated with other major cardiovascular anomalies. Lab Invest 1957;6:44–64.[Medline]
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7. Hancock Friesen CL, Zurakowski D, Thiagarajan RR, Forbess JM, del Nido PJ, Mayer JE, Jonas RA. Total anomalous pulmonary venous connection: an analysis of current management strategies in a single institution. Ann Thorac Surg 2005;79:596–606.[Abstract/Free Full Text]
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9. Hyde JAJ, Stümper O, Barth MJ, Wright JGC, Silove ED, de Giovanni JV, Brawn WJ, Sethia B. Total anomalous pulmonary venous connection: outcome of surgical correction and management of recurrent venous obstruction. Eur J Cardiothorac Surg 1999;15:735–741.[Abstract/Free Full Text]
10. Caldarone CA, Najm HK, Kadletz M, Smallhorn JF, Freedom RM, Williams WG, Coles JG. Relentless pulmonary vein stenosis after repair of total anomalous pulmonary venous drainage. Ann Thorac Surg 1998;66:1514–1520.[Abstract/Free Full Text]
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12. Bove EL, Hirsch JC. Total anomalous pulmonary venous drainage and cor triatriatum. In: Gardner TJ, Spray TL, editors. Operative Cardiac Surgery, London: Arnold Publishers; 2004:581–592.