Ann Thorac Surg 2009;87:1963-1966. doi:10.1016/j.athoracsur.2008.09.045
© 2009 The Society of Thoracic Surgeons
How To Do It
Atrial Switch Operation in a Patient With Dextrocardia, Bilateral Superior Vena Cavae, Left Atrial Isomerism and Unroofed Coronary Sinus
Sachin Talwar, MCha,
Shiv Kumar Choudhary, MCha,*,
Sandeep A. Janardhan, MSa,
Vishwas Malik, DMa,
Shyam Sunder Kothari, DMa,
Gurpreet Singh Gulati, MDa,
Thittamaranahali Kariyappa Susheel Kumar, MChb,
Balram Airan, MCha
a Cardiothoracic Centre, All India Institute of Medical Sciences, New Delhi, India
b Children's National Medical Center, Washington, DC
Accepted for publication September 11, 2008.
* Address correspondence to Dr Choudhary, Department of Cardiothoracic and Vascular Surgery, All India Institute of Medical Sciences, New Delhi, 110029, India (Email: shivchoudhary{at}hotmail.com).
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Abstract
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The present report describes the technical aspects of the atrial switch operation in the setting of dextrocardia, bilateral superior vena cavae, left atrial isomerism, and unroofed coronary sinus. Augmentation of the right atrial wall using bovine pericardium and in situ pericardial technique for construction of the pulmonary venous baffle ensured unobstructed systemic and pulmonary venous pathways.
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Introduction
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Since the advent of the arterial switch operation for managing patients with d-transposition of the great arteries, the indications of the atrial switch operation have been limited to patients presenting late, those who require atrial switch as a part of the anatomic repair of corrected transposition of the great arteries, and those with isolated atrioventricular discordance or isolated ventricular inversion [1]. However, despite early arterial switch operation in neonates, the atrial switch operation is still fairly common in developing countries due to late presentation beyond the neonatal age group [2]. There is limited data on the atrial switch operation in the presence of systemic venous anomalies and anomalies of the cardiac situs.We report the technical aspects of this operation in a patient with a combination of anomalies.
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Technique
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A 5-year-old male child with a preoperative diagnosis of d-transposition of the great arteries, intact ventricular septum with dextrocardia, and atrial situs solitus was scheduled for an atrial switch operation because of regressed left ventricular mass. On intraoperative transesophageal echocardiography, the findings were confirmed. There were bilateral superior vena cavae (SVC) with the right SVC draining into the right atrium and the left SVC draining into a dilated coronary sinus, which appeared to be unroofed. The inferior vena cava was seen to be draining into the right atrium, which appeared to be posteriorly placed.
After a median sternotomy, the innominate vein was found to be absent. The pericardium was opened in the midline. Inspection of the cardiac anatomy revealed dextrocardia, with almost all of the cardiac apex and the left ventricle under the right sternal blade. Both the right and left atrial appendages were on the left side, with the apparent right atrial appendage being the larger of the two. Bilateral SVC was present (Fig 1a). The larger right SVC drained into the right atrium, which was seen only after displacement of the heart to the left. This atrium also received the inferior vena cava, which was placed in the midline. The right superior and inferior pulmonary veins appeared small and were seen to course to the left behind the right atrium. The left SVC drained into the coronary sinus, which was dilated. The left superior and inferior pulmonary veins joined to form a chamber and it appeared to be in close continuity with the dilated coronary sinus raising the suspicion of a total anomalous pulmonary venous drainage to the coronary sinus, which was excluded by transesophageal echocardiography. After systemic heparinization, cardiopulmonary bypass was established by cannulating the aorta and the right atrial appendage. After this, both the SVCs were cannulated separately in their extra-pericardial course. The extra-pericardial part of the inferior vena cava was then mobilized and the right atrial appendage cannula was shifted to the inferior vena cava in its extra-pericardial course. Angle cannulae were used for venous cannulation. Extra-pericardial cannulation of the SVCs and inferior vena cava was preferred so that the pericardium (P-P') (Fig 1b) could be used later on in an in-situ fashion for the construction of the pulmonary venous baffle. After establishing complete cardiopulmonary bypass, the patient was cooled to 25°C. A pledgeted 5-0 polypropylene suture was placed at the apex of the heart and snared. The left pleural cavity was opened widely and with the snare, the heart was displaced into the left pleural cavity. This exposed the posteriorly placed right atrium and the right-sided pulmonary veins. A plane of dissection was then developed between the right atrium and the pulmonary veins into the interatrial groove by electrocautery dissection, so that the left atrium was exposed. The aorta was cross-clamped and cold hyperkalemic cardioplegia was administered into the aortic root. The right atrium was opened 5 mm parallel to the atrioventricular groove. Stay sutures were placed on both the lips of the atriotomy, and the intracardiac anatomy was inspected. A large secundum type of atrial septal defect was encountered through which the mitral valve and pulmonary veins draining to the left atrium could be clearly seen (Fig 1c). The coronary sinus was hugely dilated, and its opening into the right atrium was stenosed. There was an additional opening in the coronary sinus near the base of the left atrial appendage. The coronary sinus was completely laid open toward the roof of the left atrium, and the left SVC was seen draining into it. This was confirmed by passing the cardiotomy sucker tip into the coronary sinus and palpating it from outside into the left SVC. The left atrium was now opened on the right side and its edges were completely excised up to the entry of the right-sided pulmonary veins so that the opening draining the pulmonary venous blood into the pericardial cavity was large and unobstructed. The construction of the various pathways was undertaken as follows (Figs 1a–1f).
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Fig 1. (a) External cardiac anatomy shows dextrocardia with left isomerism and juxtaposed atrial appendages (arrows). The atria are not seen on the right side as they are covered completely by the ventricular mass. A stay suture (S) has been placed at the cardiac apex to facilitate displacement of the heart to the left. (Ao = aorta; IVC = inferior vena cava; LSVC = left superior vena cava; RSVC = right superior vena cava.) (b) Cannulation and landmarks. A and A' indicates the site of proposed right atriotomy. The left atrium (LA) indicates the site from where blood will exit out of the pulmonary veins. The heart has been dislocated into the left pleural cavity using the stay suture (not shown). Note the extrapericardial cannulation of the cavae. The pericardial reflection, P and P' over the superior vena cavae (SVC) and IVC is left intact. (c) The right atrium has been opened and the large atrial sepal defect can be seen along with the openings of the four pulmonary veins and a very small opening of the coronary sinus. X and X' indicates the left lip of the right atriotomy and Y and Y' indicates its right lip. (d) Construction of the posterior wall of the systemic venous baffle. A Dacron patch (DuPont, Wilmington, DE) (D) is sutured in front of pulmonary veins and behind the mitral valve. S is the left edge of the atrial septum. R is the right edge of the septum. On the right, the patch is sutured to R. The coronary sinus opening (arrow) has been cut back to open into the left atrium. The thatched area between the Dacron patch (DuPont) and the coronary sinus opening indicates the opened coronary sinus, which now drains towards the mitral valve. (e) Completion of anterior wall of systemic venous pathway. A patch of bovine pericardium (B) is sutured around the caval orifices and the left edge of the interatrial septum (S), and then this patch is sutured to the right edge of the atriotomy (along Y-Y'), thus completing the systemic venous baffle. (f) Construction of the pulmonary venous pathway using the in situ pericardial technique. P is approximated to X and P' to X'. The suture line extends from the pericardium to the atriotomy edges along the SVC and IVC and bites in the cavae must be superficial to avoid narrowing. Also when suturing the pericardium near the SVC, the area around the sino-atrial node should be avoided.
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First, working through the right atrium, a small piece of Dacron patch (DuPont, Wilmington, DE) (1.5 x 1.5 cm) was now sutured in front of the left pulmonary veins to form the posterior wall of the systemic venous pathway (Fig 1d). The suturing was started from the anterior and superior part of the roof of the left atrium anterior to the left pulmonary veins and posterior to the left atrial appendage. This suture line was continued in an anti-clockwise fashion ascending up to the rightward edge of the interatrial septum (R). With the other arm of the suture, the patch was sutured to the cut inferior edge of the coronary sinus and downward to meet the right edge of the interatrial septum, thus separating the pulmonary veins from the mitral valve and leaving the openings of the SVC, inferior vena cava, and the coronary sinus along this patch.
The next step was to construct the anterior wall of the systemic venous baffle. Because of the small right atrium, it was believed to be necessary to use additional patch material to ensure an unobstructed systemic venous baffle. A patch of bovine pericardium (B) was sutured around the caval orifices and the left edge of the inter-atrial septum (S), and then this patch was sutured to the right edge of the atriotomy (along Y-Y'), thus completing the systemic venous baffle (Fig 1e).
The next step was to direct the pulmonary venous return toward the tricuspid valve; this was performed by using the in-situ pedicled, pericardial patch technique, originally described by Shumaker in the article by Waldhausen and colleagues [3]. The pericardium on the right side (P-P') was sutured to the left edge of the right atriotomy (X-X') in such a way that P was approximated to X and P' to X' (Fig 1f). The effect of this was that the pulmonary venous return exited from the opening in the left atrium into the pericardial well and was directed toward the tricuspid valve through the pulmonary venous baffle. The aortic cross clamp was released after routine maneuvers to remove the air, and the patient was uneventfully weaned off cardiopulmonary bypass after re-warming with elective inotropic support of dopamine (5 mcg/kg/min), dobutamine (5 mcg/kg/min) and milrinone (0.5 mcg/kg/min). Post-cardiopulmonary bypass, transesophageal echocardiography demonstrated satisfactory repair. Postoperative recovery was uneventful with systemic saturation of 100% and PO
2 in excess of 100 mm Hg. Postoperative computed tomographic angiogram revealed unobstructed systemic and pulmonary venous baffles and documented satisfactory repair (Figs 2 and 3).
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Fig 2. (A, B) Computed tomographic angiogram (maximum intensity projection coronal images) to show the constructed systemic venous pathways of the left superior vena cavae (long arrow), right SVC (short arrow), and the inferior vena cava (IVC) (*) drain into the left-sided atrium.
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Fig 3. Computed tomographic angiogram (maximum intensity projection axial image) of the pulmonary veins (arrows) are directed toward the right-sided atrium by the baffle (*). This atrium connects to the right-sided morphological right ventricle (RV). The left-sided atrium connects to the morphological left ventricle (LV), which is smaller than the RV.
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Comment
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The atrial switch operation is still an important tool in the armamentarium of a pediatric cardiac surgeon, and every surgeon must be familiar with this operation. Knowledge of the various anomalies of cardiac situs and systemic venous drainage, and the modification of the classical Senning operation in the presence of these, helps the surgeon in such circumstances. The problems that we were faced with in this situation were: (1) dextrocardia necessitating a correct imagination of the direction of suturing to construct the various baffles, (2) presence of bilateral superior cavae with partially unroofed coronary sinus, (3) inadequate exposure to the posteriorly placed right atrium and the further posterior left atrium from where the pulmonary venous blood would exit into the pericardial cavity, and (4) left atrial isomerism and juxtaposition of the atrial appendages, which effectively rendered the amount of the right atrial wall tissue too less for the construction of the baffles thus risking obstruction. This kind of juxtaposition is not uncommonly encountered in patients with corrected transposition of the great arteries, because of which the free wall of the right atrium (RA) is inadequate for a standard Senning operation [4].
These difficulties in the present case were dealt with in a systematic manner. After establishment of cardiopulmonary bypass, the wide opening in the left pleura and the placement of the stay suture on the cardiac apex facilitated displacement of the heart into the left pleural cavity and provided exposure to the posteriorly placed atria. It also allowed a plane of dissection to be easily developed in the interatrial groove so that enough of the left atrium could be exposed to create an opening of sufficient size into the pulmonary venous atrium to avoid future pulmonary venous obstruction. After opening the right atrium and laying open of the coronary sinus, the redundant part of this enlarged coronary sinus tissue helped in limiting the size of the patch required to separate the pulmonary veins off the mitral valve. A Mustard type repair using autologous pericardial patch was also considered, keeping in mind the small amount of atrial wall for the systemic venous baffle. However, the pericardium is known to shrink in the long-term after a Mustard type repair and baffle obstructions are not uncommon [5]. Therefore, a generous patch of bovine pericardium was used to augment the atrium and have a large unobstructed systemic venous baffle. Although the fate of the bovine pericardium in this position will become apparent only on longer follow-up, we believe that because at least more than half of the circumference of this baffle was constructed of the autologous right atrial wall, growth potential may exist, and obstruction of the systemic venous baffle may be avoided. The final step of the operation (ie, construction of the pulmonary venous baffle) was performed according to the standard in-situ pericardial technique [3] and should have a low incidence of any future pulmonary venous obstruction issues.
We believe that our modifications, as applied to the present case, are worth sharing with our surgical colleagues, because they may also encounter these types of situations on occasion.
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References
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- Sharma R, Marwah A, Shah S, Maheshwari S. Isolated atrioventricular discordance: surgical experience Ann Thorac Sur 2008;85:1403-1406.
- Rao S. Pediatric cardiac surgery in developing countries Pediatr Cardiol 2007;28:144-148.[Medline]
- Waldhausen JA, Pierce WS, Berman Jr W, Whitman V. Modified Shumacker repair of transposition of the great arteries Circulation 1979;60:110-114.[Abstract]
- Kouchoukos NT, Blackstone EH, Doty DB, Hanley FH, Karp RH. Congenitally corrected transposition of the great arteries and other forms of atrioventricular discordant connection Kirklin and Barret-Boyes cardiac surgery: morphology, diagnostic criteria, natural history, techniques, results and indications. 3rd ed.. Philadelphia: Churchill Livingstone; 2003. pp. 1549-1584.
- Horer J, Herrmann F, Schreiber C, et al. How well are patients doing up to 30 years after a Mustard operation? Thorac Cardiovasc Surg 2007;55:359-364.[Medline]
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S. Talwar, V. V. Nair, S. K. Choudhary, and B. Airan
Atrial Switch Operation in the Current Era: Modifications and Pitfalls
World Journal for Pediatric and Congenital Heart Surgery,
January 1, 2012;
3(1):
96 - 103.
[Abstract]
[Full Text]
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Abstract
Introduction
