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Ann Thorac Surg 2005;80:733-735
© 2005 The Society of Thoracic Surgeons
a Department of Cardiology, La Timone Childrens Hospital, Marseille, France
b Department of Cardiac Surgery, La Timone Childrens Hospital, Marseille, France
Accepted for publication February 6, 2004.
* Address reprint requests to Dr Ghez, La Timones Children Hospital, 264 Rue St. Pierre, Marseille, 13385, France (Email: olivier.ghez{at}ap.hm.fr).
| Abstract |
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| Introduction |
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Herein, we describe a case of a patient with an interrupted right aortic arch, double patent ductus arteriosus, a ventricular septal defect, and isolation of the left subclavian artery (LSCA) who underwent surgical correction. Diagnosis difficulties and surgical therapeutic options are discussed.
A 4-day-old girl weighing 2.9 kg was referred to our center because of a systolic murmur. On physical examination, a 3/6 harsh precordial systolic murmur was noticed with a fixed split second heart sound. All arterial pulses were present. No arterial pressure gradient was observed between the lower and upper limbs or between the right and left arm. There was no sign of pulmonary congestion, but a mild hepatomegaly was present.
Chest radiography showed a globular heart with increased pulmonary vascular markings. Transthoracic echocardiography revealed complex lesions that combined an atrial septal defect, a large conoventricular septal defect with malalignment of the conal septum, a bicuspid aortic valve, a B-type IAA, and a double PDA. The right descending aorta appeared in continuity with the right PDA. The right ventricle was dilated with isosystemic pressures. Doppler studies showed obstruction of aortic flow (subaortic stenosis) but no sign of vascular steal.
Cardiac catheterization was performed. It confirmed the presence of an IAA and revealed an isolation of the LSCA originating from a left PDA. The large right PDA gave rise to the descending aorta and the right subclavian artery (RSCA). The right (RCC) and left (LCC) common carotid arteries arose from the ascending aorta (Figs 1, 2a).
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Under cardiopulmonary bypass and profound hypothermia, the aortic arch was directly reconstructed after ductal tissue resection. LSCA was reimplanted in the LCC, and both ductus were ligated and divided. A resection of the obstructive conal septum was performed; ventricular and atrial septal defects were closed. Sternal closure was delayed for 4 days and was associated with inotropic support and peritoneal dialysis.
The subsequent evolution was favorable. Pulses were felt in all limbs, and pressures were also equal. Control echocardiography and Doppler studies showed excellent patency of the aortic LCC/LSCA and anastomosis.
Genetic analysis revealed a 22q11 chromosomic deletion. Follow-up confirmed good results with persistent patency of the LSCA/LCA anastomosis 6 months after operation. A good flow was visualized with color Doppler imaging in the LSCA, and a strong left radial pulse was present.
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This association of lesions involves 2 different embryologic processes. On one hand, there are aortic arch anomalies (right-sided aorta and isolation of LSCA), with regression at 2 levels in the Edwards hypothetical arch system (left dorsal aorta root distal to the left PDA and 1 segment between the LCC and LSCA) [2]; on the other hand, there are conotruncal defects (aortic arch interruption and a conoventricular septal defect with posterior malalignment).
A marked association between each of these 2 groups of cardiac malformations and the chromosomic 22q11 deletion has already been reported [1, 3, 4]. The pathogenesis is unclear but may involve abnormal migration of neural crest-derived cells, which are determinants for left ventricle outflow tract and aortic arch vessel formation.
Diagnosis of this association was difficult in this patient. Clinically, the initial presentation differed from classic IAA syndrome by the absence of an arterial pressure gradient and pulse attenuation. A large ventricular septal defect and right and left PDAs explain these findings. A massive nonrestrictive left to right shunt occurred between the 2 ventricles and provoked pulmonary hypertension to systemic values. Both ductus transmitted flow and pressure from the main pulmonary artery to the descending aorta, RSCA (right ductus), and LSCA (left ductus). The entire body circulation (except for the carotid arteries) was thus ductal dependent and submitted to the same pressure regimen.
Isolation of the LSCA was not identified by ultrasonographic studies in our case. The anatomy of the left PDA (long and very sinuous) and the right aortic arch caused difficulties with diagnosis. Yet because of the high frequency of isolation or aberration of the subclavian arteries in interrupted or right aortic arches [1], we thought that supraaortic vessels should be correctly identified. We thus performed invasive investigations to guide surgical treatment, because patient status and hemodynamics were stable.
Surgical management of isolation of the LSCA may be discussed in this case. Three possibilities existed: (1) respecting left PDA and isolation of the LSCA, (2) ligation of the left PDA, or (3) reimplantation of the LSCA.
The consequences of a patent left PDA would have been deleterious. Correction of the ventricular septal defect, IAA, and right PDA would have dramatically decreased pulmonary arterial pressure. The shunt in the left ductus could have inverted to a left to right mode, leading to pulmonary vascular steal, as was reported in incomplete closure of bilateral ductus arteriosus and LSCA isolation [5, 6]. This pulmonary steal may cause heart congestion and may be complicated with subclavian steal and vertebral artery-related ischemia. We preferred a reimplantation of the LSCA to a simple ligation. Others have argued that simple ligation is faster and technically more feasible, with few consequences on the arm because of the potential development of a collateral vascular supply [1]. However, the long-term outcome is not really known with these procedures. Cases of upper limb claudication and symptomatic vascular subclavian steal subsequent to ligation have been reported many years after operation [7].
In view of the possible compromised flow in the RSCA after repair of the right-sided IAA, we preferred to reimplant the LSCA. This was accomplished during the cooling period, thus without compromising cerebral blood flow.
Subsequent analysis in the postoperative period revealed a satisfactory result, with good patency of the carotid and subclavian anastomosis on echocardiography and Doppler studies. The coexistence of IAA and isolation of an LSCA may complicate diagnosis and management, but it can be successfully treated.
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