There are many types of congenital cardiac anomalies, among which ARSA is the most frequently type of aortic arch anomalies. ARSA is often diagnosed as an incidental radiological finding due to its asymptomatic nature. However, in certain rare cases, it may manifest as compressive symptoms on the trachea and esophagus. In the pediatric age group, dyspnea is a common presenting symptom as the trachea in infants are compressible. Therefore, pediatric patients would present with the typical signs and symptoms of compression which are respiratory in nature, such as wheezing, stridor, recurrent pneumonia, and cyanosis. A few cases had been reported about pediatric patients with KD and tracheal compression who presented with symptoms that mimicked asthma.
On the contrary, respiratory symptoms are rare among adult patients. ARSA in adults often leads to esophageal compression. Thus, dysphagia to solid remains the most common presenting complaint among majority of the adult patients with ARS [3, 4]. However, our patient was completely asymptomatic and complained of neither dysphagia nor dyspnea.
In terms of diagnostic modality for ARSA patients, an esophagogram may be the initial test of choice. However, computed tomography (CT) or magnetic resonance imaging (MRI) remains the gold standard of diagnosis. Aortic CTA is the preferred investigation modality as it has a high diagnostic sensitivity and specificity for ARSA. In the interest of time and cost, we performed CTA directly for the patient. Apart from identifying the exact location and extent of ARSA, CTA is able to measure the inner diameter of the aortic dissection and the thickness of the wall in an accurate manner. This would be important to detect any pericardial and pleural effusion, mediastinal hematoma, or aortic pseudoaneurysm.
To date, ARSA complicated by type B aortic dissection is rarely reported in the literature [5]. As a result, no standard surgical approach has been established for the management of this condition. Certain asymptomatic patients are managed conservatively. However, surgical repair is warranted for patients with respiratory distress or dysphagia. In view of the persistent pain, threatened exsanguination, mal-perfusion (renal and limbs), rapid aortic enlargement, and uncontrolled hypertension in our patient, surgical repair was indicated. With an underlying ARSA, the surgical management of type B dissection represents a high level of technical difficulty and risks. Initially, TEVAR was considered as the surgical option. However, we decided against it because of the unfavorable anatomy of the underlying lesion, which included inadequate proximal and distal seal zones, tortuosity, lack of vascular access options, and extremes of aortic diameter. Therefore, open surgery was deemed as a better approach.
In the conventional approach of the open surgery for the repair of this anomaly, replacement of the affected aorta proximal to the origin of the ARSA would be performed with preservation of the ARSA. After revascularization, the diseased aortic lesion would be repaired. However, in this case, we had to adopt a novel surgical approach. Based on the imaging findings, the patient had a Stanford type B aortic dissection with a rupture in the descending aorta. The site of rupture was less than 1 cm from the left subclavian artery. Thus, it was located very closely between the right and left subclavian arteries, making it a highly complicated surgical procedure. Therefore, a novel alternative surgical repair method was devised.
During the operation, the openings to the right and left subclavian arteries were found to be obstructed after we employed the stent graft. As a result, a bypass was created to the ascending aorta. Proximal and distal anastomoses were established using artificial blood vessels. The artificial blood vessels were modelled as an ‘island-shape’ to directly match the aorta. This was able to reduce the anastomosis time and the risk of bleeding. In view of the high risk of embolization, cannulation of the carotid artery was performed and close attention was paid to brain protection throughout the operation. No brain complications were detected post-operatively.