Cross-sectional echocardiographic recognition of interruption of aortic arch between left carotid and subclavian arteries.

Interrupted aortic arch is a rare condition, usually lethal in early infancy without treatment. The only characteristic feature on conventional non-invasive investigation is peripheral pulse inequality, which indicates ductal construction, and therefore may be absent or transient and preterminal. We report the cross-sectional echocardiographic findings in seven patients with aortic arch interruption between the left carotid and subclavian arteries. Their ages were 1 day to 7 months (median 7.5 days). The arterial connection was concordant in four, double outlet right ventricle in two, and truncus arteriosus in one. In each case the ascending aorta was small in comparison to the pulmonary trunk. From the suprasternal approach the ascending aorta could be seen to terminate in the left carotid artery, and the ductus to continue smoothly into the descending aorta, with no vestige of an aortic arch linking its ascending and descending portions. The left subclavian artery was seen to arise distal to the ductus in all but one patient. All four patients with ventriculoarterial concordance had pronounced subaortic stenosis caused by posterior displacement of the infundibular septum. Cross-sectional echocardiography therefore provides the only accurate method of non-invasive diagnosis of this condition. It permits early treatment with prostaglandins to prevent ductal closure, a planned approach to cardiac catheterisation, and a further means of investigating the nature of subaortic stenosis in this condition.