Arteriographic demonstration of laceration of great vessels secondary to blunt chest trauma.

Abstract

Arteriographic demonstration of rupture or false aneurysm of the right innominate artery secondary to blunt chest trauma has been reported on several occasions (1, 3). The case reported below is the first in which arteriography demonstrates acute laceration and false aneurysm formation involving two great vessels, the right innominate and left carotid arteries. This case is also of interest in that successive arteriographic examination showed development of stenosis distal to the left carotid laceration. Case Report A 20-year-old female was pinned under the steering column of her auto after it overturned. Initial physical examination revealed normal vital signs and no significant external injury. A chest film disclosed right pneumothorax with fractured right sixth rib and mediastinal widening (Fig. 1). The findings of further mediastinal widening and a drop in hematocrit from 45 to 32 were felt to be strongly suggestive of aortic rupture. An initial aortogram (Dr. B. P. Sammons) from the right axillary route demonstrated an area of marked widening at the base of the right innominate artery diagnostic of traumatic false aneurysm. There was a suggestion of similar findings involving the left carotid artery (Fig. 2). Injection into the right innominate artery better delineated the innominate aneurysm (Fig. 3). Surgery (L. H. B.) revealed a large mediastinal hematoma and confirmed the diagnosis of innominate false aneurysm, with the intima and media lacerated. Inspection of the left carotid disclosed no definite aneurysm. Six weeks after innominate repair, examination showed a murmur over the left carotid. A selective left carotid arteriogram demonstrated persistence of the aneurysm with interval development of stenosis distal to the aneurysmal segment (Fig. 4). Surgical repair was carried out. Discussion Traumatic laceration of the great vessels is an uncommon sequel of blunt chest automobile trauma. More frequently, extracardial vascular injury involves the aortic isthmus or supravalvular area, where the forces of impact and deceleration produce the maximal shearing and torsion stresses (2). It has been speculated that great-vessel laceration may be due to a different mechanism, i.e., a combination of impact force, displacing the heart and aorta posteriorly and to the left, in conjunction with reflex hyperextension of cervical spine, resulting in maximal shearing stress at the origin of the great vessels (1). Precise premortem diagnosis depends on several factors. The only relatively specific physical finding is decreased blood pressure in the right arm, which has been noted in most previous cases of innominate avulsion. The chest roentgenogram, showing abnormal mediastinal contour and∕ or hemothorax in the absence of significant bony thoracic injury, remains the best indicator of possible vascular injury.