Asian Cardiovasc Thorac Ann 2007;15:e9-e11
© 2007 Asia Publishing EXchange Ltd
Airway Compression by Major Aortopulmonary Collaterals with 22q11 Deletion
Yukihiro Kaneko, PhD,
Hitoshi Yoda, MD1,
Keiji Tsuchiya, MD2
Department of Cardiovascular Surgery
1 Department of Neonatology
2 Department of Pediatrics, Japanese Red Cross Medical Center, Tokyo, Japan
For reprint information contact: Yukihiro Kaneko, MD Tel: 81 3 3400 1311 Fax: 81 3 3409 1604 Email: yukihirokaneko{at}hotmail.com, Deptartment of Cardiovascular Surgery, Japanese Red Cross Medical Center, 4-1-22 Hiroo, Shibuya-ku, Tokyo 150-8935, Japan.
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ABSTRACT
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Hypoxic choking episodes due to airway obstruction occurred frequently from 4 months of age in a boy with 22q11 deletion, pulmonary atresia, ventricular septal defect, absent central pulmonary artery, tracheobronchomalacia, and an aberrant right tracheal bronchus. The tracheobronchial tree was compressed by a posteriorly displaced ascending aorta and right aortic arch with aberrant left subclavian artery and major aortopulmonary collateral arteries. Single-stage unifocalization and intracardiac repair plus aortopexy at 8 months resulted in resolution of the respiratory distress and heart failure.
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INTRODUCTION
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The features of DiGeorge syndrome include tracheobronchial, arterial, and conotruncal anomalies. Tracheobronchomalacia and compression by the aorta and major aortopulmonary collateral arteries (MAPCAs) caused severe airway obstruction in an infant with DiGeorge syndrome.
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CASE REPORT
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A male twin neonate weighing 1.6 kg, who was the product of a 33-week pregnancy, was found to have pulmonary atresia (PA), a ventricular septal defect (VSD), and MAPCAs on echocardiography. Fluorescence in situ hybridization demonstrated 22q11 deletion. The other twin had a normal heart and chromosomes. Deteriorating respiratory distress necessitated mechanical ventilation from 3 months of age. Chest radiography showed hyperinflation of the right middle and lower lobes, and atelectasis in the right upper lobe. Angiography demonstrated a right aortic arch with an aberrant left subclavian artery, absent central pulmonary artery, and 4 MAPCAs. An MAPCA originating from the left carotid artery gave rise to a normally arborized left pulmonary artery. An MAPCA from the aortic arch and two MAPCAs from the descending aorta gave rise to an abnormally arborized right pulmonary artery. The two smaller right-sided MAPCAs had sufficient intrapulmonary communication with the large ipsilateral MAPCA (Figure 1
). Oximetry indicated a pulmonary-systemic blood flow ratio of 4. Bronchography demonstrated tracheobronchomalacia and localized stenoses caused by vascular compression: carinal compression by the largest right-sided MAPCA, compression of the aberrant right tracheal bronchus by the right aortic arch, and left bronchial compression by the posteriorly displaced ascending aorta and the large right-sided MAPCA (Figure 2).
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Figure 1. Preoperative aortogram; major aortopulmonary collateral artery (MAPCA) 1 gives rise to the left pulmonary artery, the large MAPCA 2 and small MAPCAs 3 and 4 give rise to the right pulmonary artery.
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Figure 2. Left: Preoperative bronchogram showing multiple stenoses (arrows); Right: The angiogram is superimposed on the bronchogram, the carina, right tracheal bronchus, and left bronchus are compressed by the largest right-sided major aortopulmonary collateral artery (MAPCA 2 in Figure 1 ), the right aortic arch, and the posteriorly displaced aorta.
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From 4 months of age, the patient experienced hypoxic choking episodes with bradycardia approximately twice a week. Arterial blood gas measurements during the most severe choking episode (pH 6.94, pCO2 183.4 Torr, pO2, 28.2 Torr, base excess 0.9) improved 9 hr after resuscitation (pH 7.52, pCO2 44.4 Torr, pO2 36.8 Torr, base excess, 11.2). Surgery was planned but postponed several times because of frequent catheter sepsis and pneumonia. At 8 months of age with a body weight of 2.2 kg, surgery was performed through a median sternotomy. After commencement of cardiopulmonary bypass (CPB), the aberrant left subclavian artery and the 2 smaller right-sided MAPCAs were ligated and divided at their origins. The 2 larger MAPCAs were detached from the aorta and the left carotid artery. They were placed horizontally behind the aorta with the proximal ends reaching the contralateral lung hila. Longitudinal apposing incisions were made in these MAPCAs, which were sutured together to create a new central pulmonary artery. The VSD was closed. A right ventricle-to-neopulmonary artery connection was created via a cryopreserved valved adult femoral vein allograft of 10 mm in diameter. After CPB, bronchoscopy-guided aortopexy was performed. Two 3/0 braided polyester sutures were placed on the anterior aspect of the ascending aorta and the retrosternal periosteum. A 3/0 braided polyester suture was placed on the right side of the aortic arch and the right thoracic wall. The threads were tightened to suspend the ascending aorta in the ventral direction with the aortic arch rightward; relief of carinal and bronchial obstructions was confirmed on bronchoscopy. The right ventricle-to-left ventricle pressure ratio before sternal closure was 0.8. The operation time was 430 min, the CPB time was 206 min, and the aortic cross clamp time was 36 min.
The patient’s respiratory distress improved gradually, allowing extubation on the 68th postoperative day. Angiography at 1 year of age revealed mild stenoses in the right pulmonary artery with a right ventricle-to-left ventricle pressure ratio of 0.5 (Figure 3). At 3 years of age, the patient weighs 6 kg and his cardiopulmonary condition is good, but there is evidence of retarded development. The cause of this retarded development might be congenital or related to the long CPB time during surgery, but it is most likely due to the severe preoperative episodic hypoxia.
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Figure 3. Postoperative right ventriculogram; the right ventricular outflow and the pulmonary artery are opacified, stenoses are observed in the right pulmonary artery.
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DISCUSSION
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Airway abnormalities are sometimes associated with 22q11 deletion. Maeda and colleagues1 reported that tracheobronchomalacia was present in 44% of patients with PA, VSD, MAPCAs, and 22q11 deletion. An association of tracheal bronchus with 22q11 deletion has been suggested.2 This patient’s phenotypic expressions (PA, VSD, MAPCAs, right aortic arch, aberrant left subclavian artery, tracheal bronchus, and tracheobronchomalacia) are all attributable to 22q11 deletion. Several cases of PA, VSD, MAPCAs, and airway compression caused by the vascular system have been reported.3–5 Two of 3 patients described by McElhinney and colleagues4 developed respiratory symptoms after single-stage unifocalization and intracardiac repair, and underwent subsequent aortopexy, while the remaining patient had preoperative symptoms and underwent single-stage repair with concomitant aortopexy. One of 3 cases treated conservatively by Yamagishi and colleagues3 died of respiratory distress, whereas the respiratory distress improved spontaneously in the other two. In a case reported by Corno and colleagues,5 prolonged tracheal intubation resolved the patient’s airway obstruction. Although spontaneous improvement may be expected in milder cases, life-threatening airway obstruction in our case warranted early surgical intervention.
There are 2 major surgical strategies for PA, VSD, and MAPCAs: staged unifocalization followed by intracardiac repair; and one-stage complete unifocalization with concomitant intracardiac repair. Currently, both strategies give excellent results.6–8 Thus, we had two surgical options in this case. The first entailed unifocalization of the right pulmonary artery, division of the large MAPCA compressing the carina, division of the left subclavian artery, and suspension of the aorta via a right thoracotomy, followed years later by intracardiac repair. The second was single-stage complete unifocalization with intracardiac repair and suspension of the aorta via a median sternotomy using CPB. The first option presented concerns of unreliable ventilation during intramediastinal manipulation with a partially collapsed right lung, and the possible hazards in the presence of aortopexy of a median sternotomy for later intracardiac repair. For these reasons, we adopted the second option, although single-stage surgery necessitates a long operation time and inherent surgical risk.
The outcome of this case suggests that single-stage intracardiac repair with aortopexy is a useful surgical option in patients with PA, VSD, MAPCAs and airway obstruction caused by vascular compression.
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REFERENCES
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- Maeda J, Yamagishi H, Matsuoka R, Ishihara J, Tokumura M, Fukushima H, et al. Frequent association of 22q11.2 deletion with tetralogy of Fallot. Am J Med Genet 2000;92:269–72.[Medline]
- Huang RY, Shapiro NL. Structural airway anomalies in patients with DiGeorge syndrome: a current review. Am J Otolaryngol 2000;21:326–30.[Medline]
- Yamagishi H, Maeda J, Higuchi M, Katada Y, Yamagishi C, Matsuo N, et al. Bronchomalacia associated with pulmonary atresia, ventricular septal defect and major aortopulmonary collateral arteries, and chromosome 22q11.2 deletion. Clin Genet 2002;62:214–9.[Medline]
- McElhinney DB, Reddy VM, Pian MS, Moore P, Hanley FL. Compression of the central airways by a dilated aorta in infants and children with congenital heart disease. Ann Thorac Surg 1999;67:1130–6.[Abstract/Free Full Text]
- Corno A, Giamberti A, Giannico S, Marino B, Rossi E, Marcelletti C, et al. Airway obstructions associated with congenital heart disease in infancy. J Thorac Cardiovasc Surg 1990;99:1091–8.[Abstract]
- Reddy VM, McElhinney DB, Amin Z, Moore P, Parry AJ, Teitel DF, et al. Early and intermediate outcomes after repair of pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries: experience with 85 patients. Circulation 2000;101:1826–32.[Abstract/Free Full Text]
- Duncan BW, Mee RB, Prieto LR, Rosenthal GL, Mesia CI, Qureshi A, et al. Staged repair of tetralogy of Fallot with pulmonary atresia and major aortopulmonary collateral arteries. J Thorac Cardiovasc Surg 2003;126:694–702.[Abstract/Free Full Text]
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ABSTRACT
INTRODUCTION
