Atypical Coarctation of the Aorta with Bilateral Vertebral-Subclavian Pathway: A Report of the First Known Case of Preligamental Aortic Arch Interruption and its Surgical Correction

Abstract

A case is reported of aortic arch interruption due to bilateral regression of the fourth branchial artery. The ductus arteriosus was closed and the ventricular septum was intact. Bilateral persistence of the dorsal aortic root had lead to anomalous origin of both sub-clavian arteries and made possible bilateral vertebral-subclavian pathways. As the right common carotid artery was lacking, the left common carotid artery represented the only continuation of the ascending aorta. The patient, a normally developed boy with highly abnormal systolic blood pressure conditions, was successfully treated by operation at the age of eight years. Complete interruption of the aortic arch in its classical form is associated with a wide patent ductus arteriosus. Accordingly, the descending aorta receives blood from the right ventricle even after birth. The invariably wide ventricular septal defect permits a left-to right shunt with its magnitude determined mainly by the pulmonary vascular resistance. Additional malformations of the aortic arch or the heart itself are common. The prognosis is poor even in the short run, and the possibilities of proper in vivo diagnosis and surgical treatment are limited (Blake, Manion & Spencer, 1962; Gasul, Arcilla & Lev, 1966; Roberts, Morrow & Braunwald, 1962; Ruiz Villa-lobos, de Balderrama, Lopez y Lopez & Castella-nos, 1961). The example of aortic arch interruption to be described here had quite different anatomical and functional manifestations. The ventricular septum was intact, and the ductus arteriosus had closed in the normal way. The anomaly, therefore, did not primarily affect the work of the right heart or the pulmonary circulation. It was haemody-namically more analogous with ordinary “adult” coarctation. Communication between both aorta segments was through an intracranial by-pass with participation of the left common carotid, both vertebral arteries and anomalous subclavian arteries. Although this anomaly appears to be unique anatomically, it belongs to a small but clinically important group with similar haemodynamic and surgical implications.