Occult cerebrovascular injury in brain injured patients

Background and purpose: Blunt cerebrovascular injury (BCVI) is a possible complication of head injury. BCVI can result in dissection, thrombosis, occlusion, and to the formation of pseudoaneuryms. Cerebral ischemia is a frightened consequence. Whereas in older reports the disorder was regarded as rare, recent studies report a much higher BCVI incidence of >1% among blunt trauma patients. There are no standardized recommendations for screening. All previous studies were performed primarily in the acute stage. The aim of our study was to investigate the frequency of undiagnosed BCVI by means of cervical ultrasound (Duplex) in a population of patients in the chronic stage of traumatic brain injury (TBI), and to correlate with MRI and clinical findings.

Subjects and Methods: In 45 consecutive TBI patients (median age 32 years) Duplex ultrasonography was performed. Median time interval between TBI and ultrasound examination was 12 months. MRI was used for the evaluation of traumatic and non-traumatic brain abnormalities. Additionally, the following clinical information was collected: type of head injury (open/closed), cause of injury (traffic accident, fall, blow/assault), and Glasgow Coma Scale score (GCS).

Results: No patient had clinical signs suspicious of BCVI. In two patients (4.4%) Duplex ultrasound revealed residues of traumatic lesions of the left internal carotid artery (ICA). In a previously healthy 27-year-old woman there was a tapering stenosis with distal occlusion of the extracranial segment. A 23-year-old man showed an irregular narrowed lumen of the extracranial ICA, highly suspicious of dissection, resulting into a pseudoaneurysm of the cavernous portion. Both patients were victims of road traffic accidents. Neither patient had clinical signs of cerebrovascular injury. However, in one patient structural MRI showed a lesion, compatible with ischemia.

Conclusions: BCVI is not rare in brain injured patients and cannot be predicted reliably. If BCVI has not been excluded before, screening is recommended also in the chronic stage of TBI. Because patients with BCVI are probably chronically more prone to cerebral ischemia, findings may influence therapy and prognosis. Moreover, they may have important medicolegal implications. Duplex ultrasonography is a useful screening tool.