Case Report

In October 2014, a 24-year-old man with a history of IAA type B presented with a pulsating bulge in his right neck, hoarseness, and a 20-mmHg blood pressure difference between arms. The patient had undergone repairs of the IAA at one week and at 6 years of age. The first repair involved placement of an 8-mm Dacron graft through a left thoracotomy, pulmonary artery banding, and closure of atrial and ventricular septal defects through a median sternotomy. During the second repair, for graft stenosis, a 16-mm Dacron interpositional graft was placed through a left thoracotomy.

At the current presentation, carotid duplex ultrasonograms showed normal results. A computed tomographic angiogram (CTA) revealed a descending thoracic aneurysm, a 5.5 × 9-cm pseudoaneurysm from the proximal to the distal anastomotic sites of the patient's 16-mm Dacron graft, and compression of the graft within the pseudoaneurysm (Fig. 1). We scheduled the patient for surgery.

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We started total cardiopulmonary bypass and induced hypothermic circulatory arrest (body temperature, 18 °C). Arterial cannulation was done through the lower descending thoracic aorta; venous cannulation, through the left femoral vein with use of a long cannula. During circulatory arrest (duration, 27 min), the bypass pump flow rate was reduced to 2 L/min; cerebral perfusion was monitored with use of near-infrared spectroscopy and remained at baseline level throughout the period of low flow. We performed a left thoracotomy, removed the previous grafts, and replaced the distal aortic arch and proximal descending thoracic aorta with a 20-mm Dacron tube-graft. We used a separate 8-mm Dacron graft to bypass the left subclavian artery. The proximal anastomosis was immediately distal to the left common carotid artery (LCCA), and the distal anastomosis was to the descending thoracic aorta just beyond the resected pseudoaneurysm.

Postoperatively, we reintubated the patient. He could not clear secretions because of left vocal cord palsy, and he had hypoxemia because of pulmonary contusions from difficult adhesiolysis during his third left thoracotomy. After left vocal cord injection, the patient recovered uneventfully. Before his discharge from the hospital on postoperative day 18, a chest CTA showed no residual aneurysms, leaks, or atypical findings (Fig. 2). Five years later, the patient was well and needed no further aortic reintervention.

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Discussion

Interrupted aortic arch, which is usually associated with other congenital cardiac anomalies,¹ constitutes approximately 1% of congenital heart disease (incidence, approximately 3 per million live births).^2,3 The main pathologic finding is loss of anatomic communication between the ascending and descending aorta.

The classification of IAA depends on the site of aortic interruption. In type A, the arch interruption occurs distal to the origin of the left subclavian artery. In type B, the interruption occurs distal to the origin of the LCCA. In type C, the interruption occurs proximal to the origin of the LCCA. Interrupted aortic arch can occur with other congenital anomalies because of genetic mutations.^4,5 It usually manifests itself as severe congestive heart failure in the neonatal period, and 90% of affected neonates die at a median age of 4 days if the IAA is not treated.⁶

The prognosis for survival after surgical repair of IAA has improved. In an early patient series (1974–1987), the 10-year survival rate was 47%,⁷ whereas in a more recent series (from 1993), the 5-year survival rate was 83%.⁸ In 2009, authors of a review noted an early mortality rate of 5% to 10% in neonates undergoing IAA repair.⁹ Variables associated with a higher mortality rate include IAA type B or C, female sex, low birth weight, truncus arteriosus, primary aortic anastomosis, concurrent complex anomalies, and earlier year of repair.^8,10–12 In addition, prolonged deep hypothermic circulatory arrest has been associated with higher mortality rates.¹³

More patients treated early for IAA are living longer, so more sequelae are seen. The Congenital Heart Surgeons' Society reports that risk factors for late reintervention include repair of truncus arteriosus, use of polytetrafluoroethylene material, and arch repair by any means other than direct anastomosis.¹⁰ In our patient's previous repairs, 2 Dacron grafts of different sizes had been used. His first reintervention at 6 years of age was needed to treat graft stenosis; the current reintervention was needed to treat a large pseudoaneurysm.

In one study of 109 reinterventions, 57 were surgical and 52 were transcatheter.¹⁰ We decided to treat our patient surgically because of his youth, the need for durable repair, and anatomic factors: the compression of the small Dacron graft by the pseudoaneurysm was better corrected openly. In conclusion, we think that expertise in both open and endovascular reintervention techniques will be necessary to deal with the range of sequelae likely to occur in long-term survivors of early IAA repair.