Clinical and radiological outcomes following traumatic Grade 3 and 4 vertebral artery injuries: a 10-year retrospective analysis from a Level I trauma center. The Parkland Carotid and Vertebral Artery Injury Survey
Authors: Scott William W. , Sharp Steven , Figueroa Stephen A. , Eastman Alexander L. , Hatchette Charles V. , Madden Christopher J. , Rickert Kim L. 
Published: October 2014

OBJECT
Grade 3 and 4 blunt vertebral artery (VA) injuries may carry a different natural course from that of lower-grade blunt VA injuries. Proper screening, management, and follow-up of these injuries remain controversial. Grade 3 and 4 blunt VA injuries were analyzed to define their natural history and establish a rational management plan based on lesion progression and cerebral infarction.

METHODS
A retrospective review of a prospectively maintained database of all blunt traumatic carotid and vertebral artery injuries from August 2003 to April 2013 was performed, and Grade 3 and 4 blunt VA injuries were identified. Grade 3 injuries were defined as stenosis of the vessel greater than 50% or the development of a pseudoaneurysm, and Grade 4 injuries were defined as complete vessel occlusion. Demographic information, radiographic imaging findings, number of imaging sessions performed per individual, length of radiographic follow-up, radiographic outcome at end of follow-up, treatment(s) provided, and documentation of ischemic stroke or transient ischemic attack were recorded.

RESULTS
A total of 79 high-grade (Grade 3 and 4) blunt VA injuries in 67 patients were identified. Fifty-nine patients with 66 high-grade blunt VA injuries were available for follow-up. There were 17 patients with 23 Grade 3 injuries and 42 patients with 43 Grade 4 injuries. The mean follow-up duration was 58 days for Grade 3 and 67 days for Grade 4 blunt VA injuries. Repeat imaging of Grade 3 blunt VA injuries showed that 39% of injuries were radiographically stable, 43% resolved, and 13% improved, while 1 injury radiographically worsened. Repeat imaging of the Grade 4 blunt VA injuries showed that 65% of injuries were radiographically stable (persistent occlusion), 30% improved (recanalization of the vessel), and in 2 cases (5%) the injury resolved. All Grade 3 injuries that were treated were managed with aspirin or clopidogrel alone, as were the majority of Grade 4 injuries. There were 3 cerebral infarctions thought to be related to Grade 4 blunt VA injuries, which were likely present on admission. All 3 of these patients died at a mean of 13.7 days after hospital admission. No cerebral infarctions directly related to Grade 3 blunt VA injuries were identified.

CONCLUSIONS
The majority of high-grade blunt VA injuries remain stable or are improved at final follow-up. Despite a 4% rate of radiographic worsening in the Grade 3 blunt VA injury group and a 35% recanalization rate in the Grade 4 blunt VA injury group, there were no adverse clinical outcomes associated with these radiographic changes. No cerebral infarctions were noted in the Grade 3 group. A 7% stroke rate was identified in the Grade 4 blunt VA injury group; however, this was confined to the immediate postinjury period and was associated with 100% mortality. While these data suggest that these high-grade vertebral artery injuries may require less intensive radiographic follow-up, future prospective studies are needed to make conclusive changes related to treatment and management.