Interact CardioVasc Thorac Surg 2009;9:528-529. doi:10.1510/icvts.2009.203901
© 2009 European Association of Cardio-Thoracic Surgery
Brief communication - Congenital |
Repair of type B interrupted aortic arch using aberrant right subclavian artery
Stephen Westaby*,
Anand Agarwal,
Jakub Kadlec and
Fidelma Flynn
Department of Congenital Cardiac Surgery, John Radcliffe Hospital, Headley Way, Headington, Oxford, OX3 9DU, UK
Received 4 February 2009;
received in revised form 11 May 2009;
accepted 14 May 2009
*Corresponding author. Tel.: +44 1865 220265; fax: +44 1865 220268.
E-mail address: swestaby{at}ahf.org.uk (S. Westaby).
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Abstract
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Interrupted type B aortic arch was repaired using aberrant right subclavian artery. In order to gain the full length of this vessel it was mobilised from a left thoracotomy. The aberrant vessel provides autogenous patch material with which to enlarge the ascending aorta and left common carotid artery.
Key Words: Interrupted aorta; Subclavian artery
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1. Introduction
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Aberrant right subclavian artery (ARSA) occurs in 0.4–2% of the population with a higher incidence in 22q11 deletion syndromes [1, 2]. In interrupted arch type B, ARSA is found in 29% of patients. Embryologically this occurs through absorption of the 4th pharyngeal arch causing the right subclavian artery to separate from the innominate artery. In a left arch there is loss of the segment between the left subclavian and carotid artery. Consequently, the ARSA originates from the descending aorta at a Kommerell diverticulum [1]. The anomaly has been replicated in a transforming growth factor β2 knockout mouse model [3]. Aberrant RSA can be an important adjunct to surgical repair of interrupted aortic arch as illustrated by the following case.
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2. Materials and methods
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A newborn 2.5 kg male infant with Di George syndrome presented with cardiovascular collapse and pulseless limbs. The carotid pulses were palpable. Echocardiography showed a perimembranous ventricular septal defect, small ascending aorta and a huge pulmonary artery. The infant was ventilated and resuscitated with prostaglandin to reopen the ductus arteriosus. A contrast computed tomographic (CT)-scan then showed type B interrupted aortic arch with ARSA originating from the descending thoracic aorta (Fig. 1a). The aortic annulus measured 4 mm and there was early bifurcation of a 4.0-mm ascending aorta into 2.5 mm carotid arteries. Vertebral arteries arose from each subclavian artery (Fig. 1b). The surgical plan was to use as much of the ARSA as possible to enlarge the left carotid artery and ascending aorta and to preserve the left subclavian artery.
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Fig. 1. Contrast computerized tomographic scan showing the aorta and brachiocephalic vessels from anterior (a) and posterior aspects (b).
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3. The surgical repair
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Arterial pressure monitoring was obtained from the right carotid and left femoral arteries. Left thorocotomy was performed first and the ARSA dissected across the posterior mediastinum to the thoracic inlet. It was ligated and a clip applied to the distal end until delivery into the anterior mediastinum. The proximal descending aorta and left subclavian artery were mobilised and the incision closed.
Median sternotomy was then undertaken and the ascending aorta and carotid arteries mobilised. The ascending aorta bifurcated early (Fig. 1a). The ductus arteriosus was dissected through the pericardial attachments to display the descending aorta and subclavian arteries. The ARSA was delivered into the operative field. Cardiopulmonary bypass (CPB) was established with arterial cannulas in the ascending and descending aorta. With hypothermic circulatory arrest (16 °C), the cannulas were removed and the ductus arteriosus divided. The ARSA was opened longitudinally extending 5 mm into the aorta adjacent to the left subclavian artery. An incision was then made from the sinotubular junction through the ascending aorta into the lateral aspect of the left carotid artery. The proximal aorta was enlarged with a pulmonary homograft patch (Fig. 2). The ARSA was used to enlarge the distal ascending aorta and left carotid artery. An arterial cannula was reinserted into the ascending aorta and CPB resumed with rewarming. The VSD was closed with a dacron patch. On discontinuing CPB there was no pressure differential between the carotid and femoral arteries. Supra-systemic pulmonary artery pressure was managed by hyperventilation and nitric oxide inhalation. After stabilisation the wound was covered with a bovine pericardial patch and the sternum left open. Delayed closure was performed 48 h later followed by uneventful recovery.
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Fig. 2. Diagram of the surgical repair. A pulmonary homograft patch has been used to enlarge the proximal ascending aorta. The ductus arteriosus was excised from the descending aorta with suture closure.
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4. Outcome
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The infant survived and is thriving. A follow-up CT-scan at 3 months shows an unobstructed aortic arch and there is no pressure differential between the right arm and femoral vessels.
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5. Discussion
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In interrupted aortic arch tension on the repair can result in anastomotic stricture and compression of the left main bronchus. In this infant, the small ascending aorta was widely separated from the descending aorta. Direct anastomosis between descending aorta and left carotid artery would have left a narrowed segment. Bacha and Sawaqued first reported the use of a segment of ARSA for type B interrupted arch repair in 2007 [4]. These authors mobilised the vessel via median sternotomy. The autologus tissue provides an ideal patch to enlarge the left carotid artery providing a neo-aortic lumen with growth potential. Our approach differed in that virtually the full length of the intra-thoracic ARSA was obtained via left thorocotomy. This approach simplified dissection across the posterior mediastinum and perhaps reduced the risk of inaccessible bleeding. As a result there was no tension or pressure gradient at the repair site.
We considered preservation of the left subclavian and vertebral artery to be important in maintaining blood flow to the spinal cord. Consequently, it was inadvisable to sacrifice both subclavian arteries in order to perform direct anastomosis between ascending and descending aorta. Although dual access involved a second incision, we considered this justified by providing a longer length of ARSA patch and possibly improved safety of the procedure overall.
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References
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- Ramaswamy P, Lytrivi ID, Thanjan MT, Ngvyen T, Srivastava S, Sharma S, Ko HH, Parness JA, Lai WW. Frequency of abberent subclavian artery, arch laterality and associated intracardiac anomalies detected by echocardiography. Am J Cardiol 2008;101:677–682.[CrossRef][Medline]
- McElhinney DB, Clark BJ, Weiberg PM, Kenson ML, McDonald-McGinn D, Driscoll DA, Zackai EH, Goldmuntz E. Association of chromosome 22q11 deletion with isolated anomalies of aortic arch laterality and branching. J Am Coll Cardiol 2001;37:2114–2119.[Abstract/Free Full Text]
- Molin DG, DeRuiter MC, Wisse LJ, Azhar M, Doetschman T, Poelmann RE, Gittenberger-de-Groot AC. Altered apoptosis pattern during pharyngeal with remodeling is associated with aortic arch malformations in Tgfbeta2 Knock out mice. Cardiovasc Res 2002;56:312–322.[Abstract/Free Full Text]
- Bacha EA, Sawaqued R. Use of the aberrant right subclavian artery in complex arch reconstruction. Ann Thorac Surg 2007;83:1566–1568.[Abstract/Free Full Text]
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Abstract
1. Introduction