Balanced Double Aortic Arch Causing Persistent Respiratory Symptoms Mimicking Asthma in an Infant

Abstract

Double aortic arch (DAA) is a common form of complete vascular ring. The condition leads to airway obstruction and compression of the esophagus. A balanced type of DAA is an extremely rare anomaly. The anatomical aberration cannot be easily distinguished by transthoracic echocardiography when an infant has chronic respiratory distress. Herein we presented a case of an 11-month-old infant who had chronic respiratory distress and a balanced type of DAA.

Introduction

The vascular ring is an uncommon congenital malformation and causes airway obstruction and compression of the esophagus. ¹ The majority of vascular rings is composed of two aortic arches. Usually one arch is patent, and the other one is atretic. Only 5 to 10% of all double aortic arches (DAA) are balanced. The clinical symptoms of balanced DAA may conspicuously appear within the first 6 months of life. Clinical manifestations of balanced DAA are mainly respiratory due to compression of the trachea. Herein we presented a case of an 11-month-old infant who had chronic respiratory distress and a balanced type of DAA. A definitive diagnosis was not made until she reached 11 months of age due to only transthoracic echocardiograms being performed. Physicians should carefully treat patients who have balanced DAA because the condition of DAA has same clinical manifestation as asthma.

Case Report

An 11-month-old infant was admitted to the emergency department (ED) with complaints of respiratory insufficiency, wheezing, mild cyanosis, and coughing. Prior to presentation at our institution, she had already been hospitalized in other hospitals three times. The patient had always been treated with albuterol and budesonide. These therapies had caused temporary amelioration in the patient's symptoms during all of her hospitalizations. However, the patient's symptoms always returned after hospital discharge. The initial physical examination in the ED revealed inspiratory and expiratory stridor with intercostal and subcostal retractions. The oxygen saturation of the patient was 94% in room air. On pulmonary auscultation, expiratory time was prolonged. The cardiologic examination of the patient revealed a grade 2/6 systolic ejection murmur, which was best heard at the left upper sternal border. Electrocardiogram was normal. Chest radiograph revealed air trapping ( Fig. 1 ). Normal cardiac structure and aortic arch were observed on the suprasternal view of transthoracic echocardiography (TTE). Once the diagnosis of reactive airway disease was made in the ED, albuterol, budesonide, and adrenaline were prescribed to the patient. Laboratory investigations and acute phase markers were normal except for a respiratory acidosis in the blood gas analysis (pH; 7,22, pCO2; 70 mm Hg, HCO3; 30 mEq/L). Nasal cannula oxygen was started as noninvasive respiratory support to supplement oxygen to treat the respiratory insufficiency. Additional treatment with intravenous magnesium and methylprednisolone was also given. Despite all these treatments, there was not any significant improvement clinically in the patient.

Fig. 1.

Chest X-ray showing air confinement.

The patient was admitted to the pediatric intensive care unit (PICU) for higher level of care. Noninvasive respiratory support treatment with bilevel positive pressure was initiated by utilizing mouth/nose mask interface and S/T mode in the PICU. There was not any significant improvement in physical examination, blood gas, and radiological findings of the patient since the admission into the PICU. We performed a diagnostic bedside bronchoscopy on the 3rd day of PICU admission to better evaluate the condition of the patient. The bronchoscopy revealed the presence of an external compression on the trachea ∼2 cm above the carina. The etiology behind the compression was the presence of a congenital vascular anomaly. We requested thoracic aorta computed tomography angiogram (CTA) to further elucidate the etiology of the compression, and to better assess the great vessels and airways of the patient. CTA revealed a DAA, passing from around the trachea and esophagus rather than descending as a single solitary aorta. The right and left aortic arch diameters were almost equal to each other ( Figs. 2 and 3 ). Also, a narrowed lower thoracic trachea was observed due to the aortic compression ( Fig. 4 ). In this case therefore, we decided that surgical aortic resection was the best treatment option due to the existence of the narrowed trachea.

Fig. 2.

The axial view of the double aortic arch from superior angle.

Fig. 3.

Thoracic computed tomography angiogram disclosing ( A ) three-dimensional image and ( B ) axial image that show the balanced type double arcus aorta.

Fig. 4.

Computed tomography angiogram showing the three-dimensional image of airways narrowed lower thoracic trachea due to compression by the aorta.

On the 5th day of PICU admission, the patient underwent operative correction by a cardiovascular surgeon. The operation was performed under general anesthesia with left posterolateral thoracotomy. A central venous line, along with right radial and right femoral arterial lines, was inserted. The left hemithorax was explored through left posterolateral thoracotomy via the fourth intercostal space. The arches, descending from the aorta, and ductus arteriosus were dissected from each other. The ductus arteriosus was ligated and divided. The anterior and posterior arches were clamped consecutively, and femoral arterial pressure was monitored to confirm the dominant arch. The nondominant arch was the posterior one, as once it was clamped, femoral arterial pressure did not change. The nondominant arch was sutured and ligated then divided ( Fig. 5 ). Adhesions around the esophagus and trachea were dissected to further relieve symptoms of compression. The operative course was uneventful, and the patient was brought to the PICU while she was still intubated. She was extubated on the 3rd postoperative day. She was discharged from the hospital due to a lack of existing respiratory problems on her 20th day in the PICU.

Fig. 5.

Intraoperative image of double aortic arch.

Discussion

The vascular ring is an uncommon congenital malformation. The anatomical manifestation of the condition is the aberrant positioning of the aortic arch and its branches. The positioning of the vascular ring encompasses both the trachea and the esophagus. The presence of the ring leads to tracheal airway obstruction and compression of the esophagus. ¹ The complete form of vascular ring is an extremely uncommon congenital cardiovascular abnormality, accounting for 0.8 to 2% of all congenital cardiovascular malformations. ² Vascular rings are composed of two aortic arches. Usually, one of the arches is patent, and another one is atretic. Fifty-five to seventy percent of all DAA are right side dominant, while 20 to 35% of them are left side dominant. Only 5 to 10% are balanced. ³ Therefore, a balanced type of DAA is an extremely rare anomaly. In toddlers under the age of 1 year with a DAA, stridor is a common clinical manifestation, accompanied with respiratory distress, recurrent respiratory infections, wheezing, and coughing. For the majority of cases, the clinical presentation of DAA occurs in infancy, within the first 6 months of life. Clinical manifestations of this condition are mainly respiratory due to compression of the trachea. Physicians, especially pediatric pulmonologists, should carefully treat a pediatric patient because the symptoms of the condition might be mistaken for asthma. ^{1 2 3 4}

Although TTE is the best noninvasive diagnostic tool to evaluate congenital cardiovascular anomalies, it is arduous to evaluate great vessels via TTE. CTA is another excellent utility to assess significant vascular anomalies and airways. DAA has different types of malformation and manifest with varying clinical symptoms. Diagnostic studies such as CTA should be kept in mind for patients who have persistent wheezing or refractory reactive airway disease to prevent delay in diagnosis of the tracheal malformation. ³ A DAA is a rare congenital aortic vessel developmental disorder that can be diagnosed in infancy and can encircle vascular ring around the esophagus and trachea. ⁵ Therefore, DAA and similar congenital vascular development disorders should be checked for patients with asthma-like symptoms who do not respond to the treatment well.

This case illustrates the challenge that pediatric pulmonologists, cardiologists, and radiologists have to face when dealing with balanced DAA that is worsened by persistent reactive respiratory airway disease and the necessary need for PICU hospitalization if a pediatric patient's condition gets worse.

Funding Statement

Funding None.