TAPVC is supracardiac (type 1) in about 45% of cases, cardiac (type 2) in about 25%, infracardiac (type 3) in about 25%, and mixed (type 4) in about 5% to 10% (see Fig. 30.1 ). The connection in supracardiac TAPVC is usually to a left vertical vein draining into the left brachiocephalic vein, less often to the superior vena cava, usually at its junction with the right atrium, and rarely to the azygos vein. In cardiac TAPVC, the connection is usually to the coronary sinus and less often to the right atrium directly. Connection to the supradiaphragmatic inferior vena cava also has been reported. The most common sites of connection in patients with infracardiac (infradiaphragmatic) TAPVC are the portal vein (65% of cases, according to Duff and colleagues ) and ductus venosus; less common are the gastric vein, right or left hepatic vein, and inferior vena cava. Uncommonly, the pulmonary venous drainage may be through two connections. Also, part of the pulmonary venous drainage may be to one site and part to another in what is termed mixed TAPVC . At least 15 different morphologic mixed variants have been identified. In the most common form, the left upper lobe of the lung drains to a left vertical vein, and the remainder of both lungs drains to the coronary sinus. In the next most common form, the right lung drains to the coronary sinus, and the left lung drains to a vertical vein. Chowdhury and colleagues have categorized this wide assortment of mixed TAPVC into three general groups: the 2+2 pattern, the 3+1 pattern, and the bizarre pattern.

No matter what the final connection or termination may be, individual right and left pulmonary veins usually converge to form a common pulmonary vein , which in turn connects to the systemic venous system in one of the ways noted earlier. It is usually posterior to the pericardium. Its long axis is usually oriented transversely, with the pulmonary veins of the left lung converging to form its left extremity and those from the right lung to form its right extremity. When the drainage is infracardiac, the right and left pulmonary veins slope downward to converge into a vertical common pulmonary vein, with the entire arrangement having a Y, T, or tree shape. Rarely, there are two vertical veins that are not confluent until below the diaphragm. Two vertical veins have also been identified in supracardiac TAPVC. A common pulmonary vein may be absent in some cases with cardiac or mixed connections. Its apparent absence in some patients may be an illusion attributable to a defect in the anterior wall of the common pulmonary vein. That defect is the orifice connecting it to the coronary sinus or right atrium.

Pulmonary venous obstruction (PVO) is a severe associated condition usually resulting from a stenosis involving the vein connecting the common pulmonary vein to the systemic venous system (e.g., an obstructed course of the vertical vein). Severe obstruction may be caused by the so-called vascular vice, in which the left vertical vein passes posterior rather than anterior to the left pulmonary artery and is compressed between it and the left main bronchus. A localized stenosis may also occur at the junction of the left vertical vein with either the left brachiocephalic vein or the common pulmonary vein, or at the junction of a connecting vein that joins the superior vena cava.

When TAPVC is to the coronary sinus, a stenosis may occur where the common pulmonary vein joins the coronary sinus or (rarely) at the coronary sinus ostium. ^, In infracardiac connection, the connecting vein may be similarly narrowed at its junction with the portal vein or ductus venosus, or it may be compressed where it penetrates the diaphragm. In those varieties of infracardiac connection in which the ductus venosus is not available to bypass the liver, the portal sinusoids offer additional important obstruction to venous return. Finally, PVO may result simply from the length of a comparatively narrow connecting vein. Rarely, associated cor triatriatum is present and serves as the cause of obstruction. ^,

Important PVO of these various types exists in nearly all patients with infracardiac connection and in almost all with connections to the azygos vein, in 65% of those with connections to the superior vena cava, in 40% of those with connections to the left brachiocephalic vein, and in 40% with connections of the mixed type. It is less common in patients with a cardiac connection, although it has been found in 20% of patients in whom the connection is to the coronary sinus. Rarely, PVO is the result of stenoses of individual pulmonary veins at or close to their connections to the common pulmonary vein. Functional PVO arguably occurs in patients having a patent foramen ovale rather than an atrial septal defect, although this occurrence may be limited to those with a small orifice at the foramen ovale.

For survival after birth, communication between systemic and pulmonary circulations must exist. Nearly always, an atrial septal defect or patent foramen ovale is present. However, in the review of Delisle and colleagues, one of 93 autopsy cases was an 11-year-old with an intact atrial septum and multiple ventricular septal defects, and Hastreiter and colleagues reported a 6-week-old patient with TAPVC to the ductus venosus, a patent ductus, and a closed foramen ovale. ^, Even though atrial communication in TAPVC is usually of adequate size and not obstructive, ^, restriction to systemic blood flow at the atrial level has been suggested to play a role in the early development of congestive heart failure in some patients. The right atrium is enlarged and thick walled in patients with TAPVC, and the left atrium is abnormally small. ^, Cineangiographic studies by Mathew and colleagues have shown left atrial volume to be 53% of predicted normal, while left atrial appendage size is preserved. The diminutive left atrium is attributed to the failure of incorporation and contribution of the embryonic pulmonary vein component during embryonic development. In addition, in patients with TAPVC to the right atrium, the posterior attachment of the atrial septum is shifted to the left, so the septum lies nearer to the sagittal than the usual coronal plane. Anatomic studies have shown that the left ventricle is usually normal in size. ^, Haworth and Reid’s quantitative study showed that inflow measurements of the left ventricle were normal in eight of nine infants dying with TAPVC. In one infant, however, left ventricular (LV) inflow measurements were abnormally small, and weight of the free LV wall plus the septum was less than that of a normal fetus at full term. In all nine infants, LV free-wall thickness was normal. In a quantitative autopsy study of infants with TAPVC, Bove and colleagues found LV mass to be normal as well. However, they found the LV cavity was small because of leftward displacement of the septum secondary to right ventricular (RV) pressure-volume overload. Correspondingly, Nakazawa and colleagues reported that angiographically determined LV end-diastolic volume (LVEDV) was 79% less than normal ( P =.009) in a group of infants with TAPVC and severe pulmonary hypertension. Hammon and colleagues also reported small LVEDV in infants with TAPVC. These findings are all compatible with those of Whight and colleagues ( Fig. 30.2 ).

Preoperative left ventricular end-diastolic volume, expressed along vertical axis as percent of predicted normal according to age and cardiac morphology. Dashed horizontal lines enclose ±2 SD from mean normal value. Open symbols represent preoperative values in seven patients, and closed symbols represent postoperative values. When both values were measured in the same patient, symbols are connected by solid lines, with two short vertical parallel lines indicating time of repair. X represents values in normal patients. CoS, Coronary sinus total anomalous pulmonary venous connection (TAPVC); Infra, infracardiac TAPVC; RA, right atrial cardiac TAPVC; Supra, supracardiac TAPVC.

(From Whight CH, Barratt-Boyes BG, Calder L, Neutze JM, Brandt PW. Total anomalous pulmonary venous connection: long-term results following repair in infancy. J Thorac Cardiovasc Surg . 1978;75:52.)

The right ventricle varies in size, depending on the magnitude of pulmonary blood flow, presence or absence of pulmonary venous stenosis, and the point at which anomalous pulmonary veins connect. When connection was infracardiac, Haworth and Reid found that the right ventricle was neither hypertrophied nor dilated. When venous connection was supradiaphragmatic, the septum and right ventricle were hypertrophied and the right ventricle dilated.

Because most infants with TAPVC have marked pulmonary hypertension, structural changes are usually found in the lungs of even the youngest infants dying with the malformation. Haworth and Reid demonstrated increased pulmonary arterial muscularity in all infants dying with TAPVC, including an 8-day-old neonate, as shown by increased arterial wall thickness and extension of muscle into smaller and more peripheral arteries than normal. Vein wall thickness was increased in all but the youngest child.

In addition, when obstruction is severe, high venous pressure can lead to secondary pulmonary lymphangiectasia, which can compromise the postoperative clinical course.

Except for atrial communication, most infants presenting with severe symptoms from TAPVC have either no associated condition or a small or large patent ductus arteriosus. Patent ductus arteriosus is present in nearly all infants coming to operation in the first few weeks of life with PVO and, overall, in about 15% of cases. Ventricular septal defects occasionally occur. However, more than one third of cases coming to autopsy, few of which are infants, have other major associated cardiac anomalies. These include tetralogy of Fallot, double-outlet right ventricle, interrupted aortic arch, and other lesions. The combination of TAPVC with other major cardiac anomalies is especially likely to occur when there is atrial isomerism (see Chapter 53 ). ^{, ,} Other associations have been identified. Esophageal varices can occur in obstructed TAPVC, and these are likely caused by obstructed veins.

Patients with TAPVC present as seriously and often critically ill neonates, especially when a component of obstruction is present. The diagnosis can be missed when obstruction is absent, because of lack of florid signs and symptoms. TAPVC must be suspected in any neonate who has unexplained tachypnea, the cardinal sign of this anomaly. During the first 2 weeks of life, there are other causes of tachypnea that may be impossible to distinguish clinically from TAPVC, particularly a diffuse pneumonic process and retention of fetal lung fluid. Meconium aspiration and myocarditis may also confound the diagnosis. Respiratory distress syndrome should not be difficult to differentiate, because of its classic radiologic features, prematurity, and intercostal and sternal indrawing. Cyanosis is usually unimpressive in TAPVC unless there is marked PVO or a widely open ductus arteriosus that permits right-to-left shunting. Both LV and RV functions are depressed compared with normal ( P <.001 in both instances) in infants presenting when seriously ill with obstructed TAPVC and marked pulmonary hypertension. ^, Severe metabolic acidosis develops soon after birth when PVO is severe, rapidly leading to myocardial necrosis. Some neonates are so critically ill that they require intubation immediately upon hospital admission and before evaluation is begun.

In neonates and infants, the heart is not particularly overactive on examination. There may be an unimpressive precordial systolic murmur and gallop sound (the latter often proves to be a tricuspid flow murmur). The second heart sound is usually single or narrowly split. In older children, the signs are those of a large atrial septal defect unless there is increased pulmonary vascular resistance.

On chest radiography, heart size is usually near normal if there is PVO, but it may be large when there is increased pulmonary blood flow. The latter is associated with plethora ( Fig. 30.3 A), but the more common PVO is evident as a diffuse haziness or, in its severe forms, a “ground glass” appearance. This sign is reduced when the pulmonary circuit can decompress via a patent ductus arteriosus. Older infants with TAPVC to the left brachiocephalic vein have a characteristic “figure-of-eight” or “snowman” configuration on the chest radiograph ( Fig. 30.3 B).

Chest radiographs of patients with TAPVC. (A) A 2.5-month-old infant with infracardiac TAPVC. Note mild cardiac enlargement and evidence of pulmonary venous hypertension. Even less radiologic change is seen in neonates. (B) “Snowman” or “figure-of-eight” configuration in a 1-year-old patient with TAPVC to left brachiocephalic vein. Shadow on left above the heart is large left vertical vein. Shadow on right is cast by large superior vena cava.

Modern echocardiography should be able to demonstrate normal pulmonary venous connection of all pulmonary veins to the left atrium in most children, including neonates. In those children where no pulmonary vein connection to the left atrium can be demonstrated, additional focused echocardiography is indicated, with TAPVC clearly in the differential diagnosis list, until proven otherwise.

Two-dimensional (2D) echocardiography is remarkably accurate in assessing the morphology of TAPVC ( Fig. 30.4 ). Along with Doppler color flow interrogation, it is almost always diagnostic. Echocardiographic features include criteria for RV diastolic overload and an echo-free space posterior to the left atrium. However, a second drainage site might be overlooked. Other echocardiographic clues that should direct toward a TAPVC diagnosis are exclusive right-to-left shunting at atrial level, a small left atrium, and a dilated caval vein. Echocardiography is commonly accepted as a definitive diagnostic procedure in neonates with important PVO, because contrast medium is not required. Cardiac catheterization delays operation and exacerbates myocardial failure and pulmonary edema.

Two-dimensional echocardiogram of an infant with total anomalous pulmonary venous connection. There is no connection of common pulmonary vein to left atrium. AV, Atrioventricular; LA, left atrium; PV, common pulmonary vein; RA, right atrium.

Prenatal echocardiography: prenatal diagnosis of TAPVC affects the postnatal outcome, particularly in obstructive forms, because planned delivery and perinatal management are mandatory. TAPVC is, however, under- and misdiagnosed in utero, with prenatal detection rates of less than 2%. Fetal 2D and 3D ultrasonography may improve the prenatal diagnosis of TAPVC.

Paladini and colleagues published a systematic review describing the sonographic features and associated anomalies of TAPVC in the prenatal setting. They concluded that leading sonographic signs are ventricular disproportion (right ventricle > left ventricle), increased area behind the left atrium, and the finding of a vertical vein. Prenatal diagnosis was established by using color or power Doppler in 85% of cases. Obstructed venous return can be expected in roughly one-third of cases of TAPVC, and outcome is favorable in less than half of cases.

Angiograms obtained by pulmonary artery or pulmonary vein injections define the malformation, identify the site of drainage, and often localize the site of PVO. When the connection is to a left vertical vein, the common pulmonary vein and vertical vein can usually be demonstrated ( Fig. 30.5 A). When the anomalous connection is to the coronary sinus, it appears as an ovoid opacification over the left side of the spine within the right atrial contour. When it is infracardiac, the descending vein can usually be demonstrated, although its precise infradiaphragmatic connection may not be seen ( Fig. 30.5 B).

Angiograms of infants with TAPVC. (A) TAPVC to left brachiocephalic vein. (B) TAPVC draining infradiaphragmatically.

Umbilical vein catheterization permits direct injection of contrast medium into the anomalously connecting infradiaphragmatic vein and an accurate diagnosis of its connections. Presence of PVO is established by demonstrating a gradient between left atrial and pulmonary artery wedge pressures. In the current era, the role of diagnostic cardiac catheterization and angiography is very limited. Noninvasive diagnostics modalities provide sufficient anatomic and pathophysiologic information in almost all cases. Even though cardiac catheterization can provide useful information, this invasive and time-consuming option should not be used in seriously ill neonates and should not result in treatment delay.

Because of diagnostic limitations of echocardiography in complex cases and morbidity associated with cardiac catheterization in gravely ill patients, both magnetic resonance imaging (MRI) and computed tomography (CT) have become increasingly important in diagnosing TAPVC ( Table 30.1 ). Both modalities should be used selectively, primarily in patients in whom echocardiography is not definitive. When compared with both catheterization and echocardiography, numerous studies have demonstrated the accuracy of MRI and CT in diagnosing TAPVC. Several demonstrate improved accuracy of diagnosis using both helical CT angiography, with and without 3D reconstruction, and gadolinium-enhanced 3D cardiac magnetic resonance (CMR) angiography. ^,

Even though CT provides superior spatial resolution and is fast in assessing 3D dimensional anatomy, MR provides, in addition to anatomic data, valuable functional data, volumetry, and flow analysis that may be used to calculate degree of right heart enlargement and shunt fraction to determine the functional importance of lesions. ^,

In TAPVC, the right atrium is theoretically a common mixing chamber. This situation is reflected in the frequent finding of close similarity of oxygen content and saturations from the right atrium, left atrium, pulmonary artery, and systemic artery. There is considerable deviation from this pattern, however, because of streaming of systemic venous return in the right atrium, directing inferior vena caval blood through the foramen ovale to the mitral valve, and superior vena caval blood through the tricuspid valve. Thus, in infracardiac TAPVC, systemic arterial saturation is typically higher than pulmonary artery saturation. In supracardiac TAPVC in the presence of patent ductus arteriousus (PDA), reversed differential cyanosis can be observed, with upper extremity oxygen saturation being lower than in the lower body.

Because TAPVC has this common mixing chamber, in most patients who live beyond infancy, a direct relationship exists between the magnitude of pulmonary blood flow and arterial oxygen saturation, assuming a constant oxygen consumption and blood hemoglobin level. This relationship was formulated into a nomogram by Burchell ( Fig. 30.6 ). Because the pulmonary/systemic blood flow ratio ( Q ˙ p/ Q ˙ s ) in such patients is determined primarily by magnitude of the pulmonary blood flow, and because their pulmonary vascular resistance is inversely related to pulmonary blood flow, arterial oxygen saturation in children (not in seriously ill neonates and young infants) is a rough guide to the patient’s operability vis-à-vis pulmonary vascular disease. When, in children and adults, arterial oxygen saturation is less than about 80%, the Q ˙ p/ Q ˙ s is likely to be less than 1.4 and pulmonary vascular resistance greater than 10 U · m ² .

Relation between percent arterial oxygen saturation and pulmonary blood flow in persons with common mixing chambers, formulated on theoretical grounds by Burchell. The upper curve is at rest; the lower is at moderate exercise. Systemic blood flow is assumed to be 25 L · min ⁻¹ .

(From Burchell HB. Total anomalous pulmonary venous drainage: clinical and physiologic patterns. Mayo Clin Proc . 1956;31:161.)

After establishing CPB, ligation of the ductus arteriosus and cooling the patient, the common pulmonary vein, lying behind the pericardium, is identified after lifting up the apex of the heart for a moment to visualize the retrocardiac portion of the pericardium. The right pulmonary artery, running parallel and just cephalad to the common pulmonary vein, is also identified to avoid confusing it with the common pulmonary vein. The vertical vein connecting the common pulmonary vein to the left brachiocephalic vein can sometimes be seen inside the pericardium, but in most cases the pericardium on the left must be retracted toward the patient’s right and the persistent left vertical vein identified beneath the mediastinal pleura. The vein is isolated after carefully identifying and avoiding injury to the left phrenic nerve.

Cardioplegic cardiac arrest is established after cross clamping the aorta. The common pulmonary vein can be exposed in several ways. One method approaches the common pulmonary vein from the right side of the heart. The posterior pericardial reflection is opened ( Fig. 30.9 A), and the common pulmonary vein is opened ( Fig. 30.9 B-C). The posterior left atrial wall is opened, the incision is extended toward the left atrial appendage, and an adequate sized anastomosis is then made between the common pulmonary vein and left atrium ( Fig. 30.9 D-F). The continuous suture line must not be pulled up so tightly as to purse-string the anastomosis and narrow it. It is helpful to place several interrupted sutures at the completion of the anastomosis to prevent purse-stringing (see Fig. 30.9 F). The right atrium is opened and the foramen ovale or atrial septal defect is closed. The remainder of CPB and reestablishment of myocardial perfusion are completed (see Chapters 2 and 3 ).

Repair of TAPVC to left brachiocephalic vein, right lateral approach. (A) Posterior pericardial attachments of heart are cut, allowing cavae and atria to be lifted completely free of common pulmonary vein, which is behind the pericardium. Left vertical vein is exposed, preferably from within the pericardium. If extrapericardial exposure is required, the phrenic nerve is elevated off the pericardium and vein. This dissection must be done sharply and with perfect exposure and visibility, because damage to this vein might necessitate its premature ligation. In this case, the common pulmonary vein would have to be opened immediately to prevent severe pulmonary venous hypertension. Also, the dissection must identify the site of connection of the uppermost left pulmonary vein so that the vertical vein may be ligated superior to that point. (B) With ventricles in normal position in the pericardium, exposure for repair (and for repair of other types of TAPVC) is obtained by elevating atria up and to the left. Posterior pericardium over common pulmonary vein and its anterior wall are opened parallel to its long axis. (C) Incision should be made over full length of the common pulmonary vein. Orifices of left and right pulmonary veins are located and inspected, and care is taken to avoid damaging them. A corresponding incision is made more or less transversely in the back wall of left atrium. The incision may need to be carried onto the base of the left atrial appendage to gain sufficient length. It is carried to the atrial septum on the right, but care is taken not to enter the septum itself. When in doubt about initial placement of the left atrial incision, it is helpful to pass a small curved clamp through an incision in the right atrial wall and through the foramen ovale so that its tip tents the back wall of the left atrium outward. (D) Traction sutures of 5-0 polypropylene are placed on inferior and superior lips of the incision into the common pulmonary vein; both the vein wall and posterior pericardium are caught with these sutures and with the suture line. Anastomosis is begun at the point shown, with the first stitch placed from outside to inside in the atrial wall, allowing suture line to be made from inside the vessels. (E) Suture line is carried toward and around the left-sided angle of the incisions and along most of the superior side. The previously held other end of the double-armed 6-0 or 7-0 polypropylene or polydioxanone stitch is then used to approximate, in similar fashion, the inferior edge. Here the stitches are placed from outside to inside on the common pulmonary vein and from inside to outside on the atrial wall. Suture line is carried nearly to the right-sided angle. (F) Suture line is then completed, either with a few interrupted stitches or as a continuous stitch.

(B from Kirklin JW. Surgical treatment of total anomalous pulmonary venous connection in infancy. In: Barratt-Boyes BG, Neutze JM, Harris EA, eds. Heart Disease in Infancy: Diagnosis and Surgical Treatment . Edinburgh: Churchill Livingstone; 1973:89.)

A second method of repairing the TAPVC is by exposing the common pulmonary vein from the left side of the heart by lifting the heart out of the pericardial sac by retracting the cardiac apex anteriorly and rightward. The incision in the common pulmonary vein is made under direct vision. The back of the left atrium is also exposed by this maneuver and is incised. The anastomosis is then made in a fashion similar to that described in the preceding text.

A third method of repairing TAPVC to the left brachiocephalic vein is via a right atrial approach. This method has the advantage of allowing the anastomosis of the common pulmonary vein to the left atrium to be performed in precise anatomic relationships, because there is no retraction or displacement of critical structures to gain exposure. The right atrium is incised parallel to the atrioventricular groove ( Fig. 30.10 A), exposing the atrial septum. The septum primum is excised to enlarge access to the left atrium. The posterior wall of the left atrium is incised transversely ( Fig. 30.10 B) into the free pericardial space behind the atrium. The common pulmonary vein is identified lying beneath the pericardium directly behind the incision in the left atrium. An incision is made in the common pulmonary vein, which extends from the bifurcation on the left side to the bifurcation on the right side (see Fig. 30.10 C). A large anastomosis is constructed between the common pulmonary vein and left atrium ( Fig. 30.10 D). This anastomosis has little chance for distortion because it is performed without displacing anatomically adjacent structures. Repair is completed by closing the atrial septal defect with a pericardial patch ( Fig. 30.10 E).

Repair of total anomalous pulmonary venous connection to left brachiocephalic vein, right atrial approach. (A) Right atrium is incised parallel to atrioventricular groove. Membrane of foramen ovale is excised. (B) Posterior wall of left atrium is incised transversely into pericardial space behind it. (C) A long incision is made in common pulmonary vein, which extends from the pulmonary vein bifurcation on the left side to the right side. (D) Common pulmonary vein is anastomosed to left atrium using continuous stitches of 7-0 polypropylene or polydioxanone suture. Suture line is started at apex of the common pulmonary vein incision on the left side, placing stitches from inside the pulmonary vein. (E) Foramen ovale is closed with pericardial patch to increase capacity of left atrium.

A variant of the right atrium approach utilizes a transverse right atrium incision extended across Waterston groove toward the left atrium and septum. This provides maximum exposure to the retro cardiac pericardium, without retraction or displacement of critical structures. After a conventional or sutureless anastomosis of the pulmonary venous confluence to the left atrium, patch closure of the atrial septum allows enlargement of the left atrium. The dilated right atrium can be closed primarily.

A common pulmonary vein is usually present in the rare anomaly of TAPVC to the superior vena cava, providing free communication between right and left pulmonary veins. After the presence of the common pulmonary vein is confirmed by direct inspection (see “ TAPVC to Left Brachiocephalic Vein ” earlier), the operation proceeds in the same manner as described for patients with TAPVC to the left brachiocephalic vein, using the right atrial approach. The connection into the lower part of the superior vena cava is identified, and palpation is performed with a right-angled clamp to confirm the anatomic details. The sinus is disconnected from the superior vena cava by cutting across the connection. The resultant opening in the common pulmonary vein is extended in both directions and the anastomosis to the left atrium is made. The site of connection into the superior vena cava is then easily closed from within the right atrium, using a pericardial patch. The right atrium is then closed, rewarming begun, and the remainder of the operation completed as described for patients with connection to the left brachiocephalic vein.

The right atrial approach described in the preceding text is used. The right atrium is opened by the usual oblique incision. The repair most commonly used includes excising both the roof of the coronary sinus, so that it communicates freely with the left atrium, and the fossa ovalis ( Fig. 30.11 A-B). The resulting large defect, made up of a confluence between the rim of the fossa ovalis and the coronary sinus ostium, is then closed with a pericardial patch, taking into account the conduction system ( Fig. 30.11 C).

Repair of total anomalous pulmonary venous connection to coronary sinus. (A) Incision is made in right atrium parallel to atrioventricular (AV) groove. Membrane of foramen ovale is excised and roof of coronary sinus incised. (B) Roof of coronary sinus is cut back into left atrium so that it communicates freely with left atrium. Conduction system (AV node) is located in atrial septum opposite incision in coronary sinus. (C) Large defect is closed with pericardial patch.

However, occurrence of stenosis at the repair site late after operation has prompted use of the technique described by Van Praagh and colleagues. The foramen ovale is enlarged to obtain an adequate exposure within the left atrium ( Fig. 30.12 A). The wall between the coronary sinus and left atrium is incised ( Fig. 30.12 B), and the incision is enlarged as much as possible in both directions. The foramen ovale and coronary sinus ostium are closed separately ( Fig. 30.12 C). The pulmonary veins then drain into the left atrium through the surgically unroofed coronary sinus ( Fig. 30.12 D). The remainder of the operation is completed as described for other types of TAPVC.

Repair of total anomalous pulmonary venous connection to coronary sinus, Van Praagh method. (A) After usual preparations, right atrium is opened obliquely and exposure arranged. Foramen ovale is enlarged cephalad and at times caudad to attain adequate visibility within left atrium. (B) An opening is made in the common wall between coronary sinus and left atrium after wall has been tented with right-angle forceps. This opening is enlarged downward and to the left; care must be taken not to go outside the heart in the process. (If this occurs, the opening must be closed at this point from within the heart by a few sutures, because the area is difficult to expose from outside the heart.) The incision is carried anteriorly and to the right to within a few millimeters of the ostium of the coronary sinus. (C) Foramen ovale and ostium of coronary sinus are closed, usually individually, with interrupted or continuous suture. Suture line should start inferiorly just below the last tiny coronary vein entering the sinus and, as it proceeds superiorly, should be made with shallow bites and preferably kept within the coronary sinus ostium to avoid the atrioventricular (AV) node. (D) Arrow indicates path of blood flow through the coronary sinus to the right atrium before repair. After repair, blood flow from the coronary sinus is to the left atrium above the mitral valve through the unroofed coronary sinus.

(From Van Praagh R, Harken AH, Delisle G, Ando M, Gross RE. Total anomalous pulmonary venous drainage to the coronary sinus: a revised procedure for its correction. J Thorac Cardiovasc Surg. 1972;64:132.)

Obstructed pulmonary venous drainage can occur in patients with TAPVC to the coronary sinus. Thus, the surgeon must be prepared to abandon usual approaches if a stenosis is proximal to the coronary sinus itself, and proceed to anastomose the common pulmonary vein, which is actually the junction of the right and left pulmonary veins, to the back of the left atrium.

Initial stages of the operation are as described for other types of TAPVC using the right atrial approach. The right atrium is opened obliquely. The anomalous connection into the right atrium is explored with an instrument to verify the presence of a confluent pulmonary vein. The foramen ovale is then enlarged, and working through it, an incision is made in the posterior left atrial wall. The common pulmonary vein is visualized through this incision, and its anterior wall is incised. This opening is enlarged and anastomosed to the left atrial incision, still working from within the atria. The enlarged foramen ovale is closed by direct suture. The original connection of the common pulmonary vein to the right atrium is closed with a relatively small pericardial patch; it must be remembered that the pulmonary venous pathway from the right lung is beneath the patch.

Alternatively, as described for the repair of TAPVC to the superior vena cava, the common pulmonary vein can be detached from the right atrium, the opening is enlarged and used for anastomosis to the left atrium, and the resulting defect in the posterior atrial wall closed. The remainder of the operation is completed as usual.

In TAPVC to an infradiaphragmatic vein, the distal (inferior) portion of the common pulmonary vein is vertical, and proximally (superiorly) it forms a Y or T connection with the left and right pulmonary veins. Therefore, after initial stages of the operation have been performed as described for other types of TAPVC, a decision is made about the approach, which may be similar to that for other types, through the opened right atrium, or through the back of the left atrium directly after tilting the apex of the heart up and to the right. Good results have been obtained by all approaches. The approach using retraction of the cardiac mass out of the pericardial sac is described. The heart is freed from its posterior attachments and the back of the left atrium exposed ( Fig. 30.13 A). The common pulmonary vein and left atrium are incised ( Fig. 30.13 B). The common pulmonary vein is anastomosed to the back of the left atrium ( Fig. 30.13 C), is ligated ( Fig. 30.13 D), and may be divided to allow the anastomosis to conform better. ^,

Repair of total anomalous pulmonary venous connection draining infradiaphragmatically. (A) Exposure of common pulmonary vein and posterior wall of the left atrium is obtained by tilting the heart superiorly and to the right. Common pulmonary vein is identified behind the pericardium posteriorly. (B) Posterior wall of left atrium is incised beginning at base of the appendage and somewhat more vertically than for other types of repair of TAPVC. A long incision is made in the common pulmonary vein. (C) Anastomosis of common pulmonary venous sinus to left atrium is constructed using 6-0 or 7-0 polypropylene or polydioxanone suture. Anastomosis is started at the apex superiorly, working from within the left atrium and common pulmonary vein. (D) The common pulmonary vein is ligated below the anastomosis, with care taken to place ligature below any pulmonary vein branch.

Some rare types of TAPVC occur, such as connection to the azygos vein or inferior vena cava, or dual connection from the common pulmonary vein. ^{, , ,} These connections can usually be sorted out using MRI or CT. In the rare event that the connection cannot readily be found or dissected out at operation, the common pulmonary vein is opened and the connection(s) identified from within it. After the connection is closed, the usual anastomosis is made between the common pulmonary vein and left atrium.

Patients with mixed TAPVC present a diagnostic as well as surgical challenge. MRI or CT is almost always used to supplement echocardiographic imaging and to provide an accurate characterization of the morphologic details. Chowdhury and colleagues have recently categorized the spectrum of mixed TAPVC into five major groups. ^, Each group is characterized by a set of similar general morphologic patterns, but many variations occur from case to case.

Management of each patient must be individualized based on analysis of the mixture presented. A variety of techniques must be used, including many of those already described for TAPVC to the left brachiocephalic vein, right atrium, superior vena cava, and structures below the diaphragm. Combining these techniques with others, such as construction of a right atrial intracardiac baffle for isolated veins to the superior vena cava (similar to repair of partial anomalous pulmonary venous connection) or direct anastomosis of isolated left upper pulmonary vein to the left atrial appendage, will usually allow complete repair. In some small babies in whom an extensive operation would be required for complete one-stage repair, subtotal repair can be successful, leaving unrepaired, for example, anomalous connection of the left upper lobe to the left brachiocephalic vein.