Interact CardioVasc Thorac Surg 2008;7:1176-1177. doi:10.1510/icvts.2008.188003
© 2008 European Association of Cardio-Thoracic Surgery
Enlarged bronchial collateral artery complicating recovery after arterial switch for simple transposition of the great arteries
Claire Irving and
Milind Chaudhari*
Department of Paediatric Cardiology, Freeman Hospital, Newcastle upon Tyne, NE7 7DN, UK
Received 9 July 2008;
received in revised form 10 August 2008;
accepted 12 August 2008
Corresponding author. Tel.: +44 191 223 7484; fax: +44 191 223 1317.
E-mail address: milind.chaudhari{at}nuth.nhs.uk (M. Chaudhari).
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Abstract
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Enlarged bronchial collateral arteries can lead to significant left to right shunting resulting in pulmonary hypercirculation and hypoxemia and may complicate postoperative recovery after uneventful surgical repair. We describe a case of simple transposition of the great arteries in which the postoperative course was complicated by the presence of an enlarged bronchial collateral artery causing pulmonary oedema necessitating prolonged mechanical ventilatory support. Successful coil embolisation of the bronchial collateral resulted in resolution of the pulmonary oedema and successful extubation.
Key Words: Neonate; Cardiac catheterization/intervention; Transposition of the great arteries
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1. Case summary
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A male infant was born in good condition at 42 weeks' gestation with a birth weight of 2.8 kg. At 14 h of age he was noted to be centrally cyanosed with oxygen saturations of 70% in air. Subsequent echocardiography diagnosed simple transposition of the great arteries (TGA). The great vessels had an anterior–posterior relationship and the coronary arteries were normal with the right coronary artery arising from the right posterior facing sinus, and the left coronary artery from the left posterior facing sinus, giving rise to the left anterior descending and circumflex coronary arteries.
He was started on prostaglandin E1 at 20 ng/kg/min and a balloon atrial septostomy was performed via a left femoral venous approach at 20 h of age. On the 11th day of life he underwent an uncomplicated arterial switch procedure. Bypass time was 159 min with a cross-clamp time of 79 min and a circulatory arrest time of 12 min. He was weaned off bypass on milrinone and adrenaline. His postoperative recovery was complicated by features of pulmonary hypercirculation with pulmonary oedema on the chest X-ray and pulmonary hypoxaemia requiring prolonged ventilatory support with high inspiratory pressures and persistent oxygen requirement. Echocardiography demonstrated good biventricular function with no intracardiac shunts and no outflow tract obstruction, and inotropic support was successfully weaned. His ECG was normal with no evidence of myocardial ischaemia. A trial of extubation was failed on day five due to pulmonary oedema and pulmonary hypoxaemia. There was no atelectasis or consolidation on chest X-ray to suggest a primary respiratory cause for this failed weaning of support. A repeat echocardiogram at this stage demonstrated continuous left to right flow from the aorta to the pulmonary artery with increased pulmonary venous return to the left atrium. There was mild tricuspid regurgitation with no evidence of pulmonary hypertension. A subsequent angiogram showed a large tortuous bronchial collateral artery arising from the descending thoracic aorta and supplying the right lung (Fig. 1). Small bronchial collaterals supplying the left lung were also identified but were restrictive with little flow on contrast injection. The branch pulmonary arteries were of normal size and distribution and there were no intracardiac shunts. Coil embolisation of the enlarged bronchial collateral supplying the right lung (Fig. 2) was followed by resolution of the pulmonary oedema, successful weaning from mechanical ventilatory support and successful extubation within 48 h. His subsequent hospital course was uneventful and he was discharged home on the 19th postoperative day.
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Fig. 1. Angiogram with contrast filling the enlarged bronchial collateral artery (white arrow) and hyperperfusion of that area of the right lung.
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2. Discussion
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Pathologic and angiographic studies have documented enlarged bronchial collateral arteries in patients with transposition of the great arteries [1, 2]. Late surgical ligation or coil embolisation of these collaterals for relief of pulmonary hypoxaemia and pulmonary hypercirculation is reported following atrial switch and arterial switch operations [2, 3]. However, significant bronchial collaterals complicating early postoperative recovery following neonatal arterial switch is extremely rare. One previous report has described fatal airway bleeding due to an enlarged bronchial collateral artery after neonatal arterial switch for simple TGA [3]. Our report describes a rare case in which postoperative recovery after arterial switch for simple TGA was complicated by a previously unrecognised enlarged bronchial collateral artery.
Hypoxaemic respiratory failure in this situation may be due to a variety of factors however, and it is important to exclude primary respiratory causes for deterioration such as atelectasis or infection. In preterm or small for gestational age infants in whom surgery is undertaken relatively early, consideration should also be given to the possibility of pulmonary immaturity or surfactant deficiency. Other causes could include pulmonary hypertension which is often easily excluded on echocardiography, ventilation/perfusion mismatch due to excessive systemic vasodilation (for example resulting from inotropic support with Milrinone) or post-perfusional pulmonary oedema. In our case, these alternatives were considered but our management plan was simplified by the echocardiographic findings. It is possible that the left-to-right shunt, from the bronchial collateral artery in this situation increased and became more apparent as cardiac output improved during the postoperative period.
Abnormally enlarged bronchial collateral arteries can be undiagnosed in simple TGA [4] as preoperative angiography is now rarely performed and morphology is accurately demonstrated on echocardiography prior to arterial switch operation. Moreover, enlarged bronchial collateral arteries can be masked in this scenario by the presence of a patent ductus arteriosus (PDA) on the initial echocardiogram. Inability to clearly distinguish between a large PDA and the presence of collateral arteries on initial echocardiographic screening may lead to under diagnosis of these additional vessels which may only become apparent postoperatively once the presence of the PDA is no longer a confounding factor in obscuring a left-to-right shunt at this level on colour Doppler. It is therefore important in the preoperative assessment to consider the possibility of and to look for these vessels which may become problematic at a later date.
Unexplained pulmonary hypoxaemia with pulmonary hypercirculation after arterial switch should therefore raise the possibility of enlarged bronchial collaterals. Prompt angiographic evaluation followed by coil embolisation will result in symptomatic relief and aid early postoperative recovery.
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References
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- Wernovsky G, Bridges ND, Mandell VS, Castañeda AR, Perry SB. Enlarged bronchial arteries after early repair of transposition of the great arteries. J Am Coll Cardiol 1993;21:465–470.[Abstract]
- Aghaji MAC, Friedberg DZ, Burlingame MW, Litwin SB. Hypoxemia and pulmonary hyperperfusion after total repair of transposition of the great arteries. J Cardiovasc Surg 1989;30:338–341.[Medline]
- Golej J, Trittenwein G, Marx M, Schlemmer M. Aortopulmonary collateral artery embolization during postoperative extracorporeal membrane oxygenation after arterial switch procedure. Artif Organs 1999;23:1038–1040.[CrossRef][Medline]
- Nair KKS, Chan KC, Hickey MS. Arterial switch operation: successful bilateral internal thoracic artery grafting. Ann Thorac Surg 2000;69:949–951.[Abstract/Free Full Text]
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Abstract
1. Case summary