Interrupted aortic arch (IAA) is a rare congenital heart condition first described by Steidele in 1773. The condition accounts for less than 1% of congenital heart conditions and is part of a broader spectrum of heart anomalies in 97% of affected children.
In affect individuals, the aorta is completely discontinuous somewhere between the ascending and descending parts. Most of these comprise ventricular or atrial septal defects. Others include anomalies of the mitral valve, of the ductus arteriosus, or of the ventricular outflow tract. Without treatment, all children with this condition will die within 10 days and treatment must therefore be on an emergency basis.
Interruption of the aortic arch occurs at three locations, as classified by Celoria and Patton:
- Type A: distal to the left subclavian artery
- Type B: between the left common carotid and left subclavian arteries
- Type C: between the innominate and left common carotid arteries
Of these, type B is the most frequently seen.
Symptoms and signs
An interrupted aortic arch is often compensated for at birth by a right-to-left shunt across the patent ductus arteriosus. In other words, the head and neck, and the upper limbs, are supplied by the proximal part of the aorta.
At the same time, the ductus arteriosus is still open, allowing blood from the pulmonary artery to reach the distal part of the aorta (shunting across the interruption) and thus supply the systemic circulation in the lower part of the body.
Symptoms appearing in early neonatal life include:
- Poor feeding
- Cutting off of feeds due to fatigue and shortness of breath
- Sweating and cold, clammy skin
- Vomiting because of insufficient circulation to the digestive tract
Clinical signs of this condition occur:
- Grayish tinge to the skin or cyanosis
- Low conscious level
- Poor capillary refill in the legs due to low blood flow
- Absent femoral pulses with normal upper limb pulses, with corresponding differences in the blood pressure between the upper and lower limbs
- Rapid shallow breathing
- Low urine output
- Metabolic acidosis
Diagnosis and management
The infant with interrupted aortic arch is not usually sick at birth. To keep the ductus arteriosus open is of paramount importance, and prostaglandin E1 infusion is therefore maintained. In addition, mechanical ventilation is required in most cases.
The definitive management is surgical. Corrective surgery consists of reconstructing the aortic arch in various ways. The procedure is usually performed under a cardiopulmonary bypass, with induced hypothermia. The discontinuous ends of the aorta are excised and anastomosed, either using arterial tissue or a synthetic graft.
A one-stage or multiple-stage repair is possible, depending on the complexity of the anomaly and the infant’s general condition. The ventricular septal defect is repaired at the same time. The survival ranges from 54 to 81%, based on the extent of the anomaly.
Highest survival rates are observed in the one-stage repair with augmentation of the aortic arch or ascending aorta. The outcome is dependent on the presence of other serious anomalies as well. Reoperation is required in a significant number of cases.
Reviewed by Yolanda Smith, BPharm