A Tale of Two Cities: Screening for Blunt Cerebrovascular Injury

Blunt cerebrovascular injury (BCVI) is an uncommon, but potentially devastating consequence of blunt trauma to the neck. It is estimated at 1-2% of all blunt trauma patients, though this number was just 0.1% prior to the institution of screening protocols. It is typically secondary to hyper-flexion or hyper-extension injury of the neck (i.e. high speed MVC), or a direct blow (i.e. clothesline injury). Either the carotid or vertebral arteries can be affected, with the major sequelae of interest being ischemic stroke post-injury. This can be immediate or delayed in nature. Due to its relative rarity but severe potential morbidity, screening protocols have been devised and introduced across North America.

During my time on the Cook County Trauma Unit, I have noted a great many differences from my home hospital at Vancouver General Hospital (VGH) in British Columbia, Canada. While differences in penetrating trauma were expected, given vast differences in experience and volume, the differences in management of blunt trauma patients were far more unexpected. Most pronounced was the difference observed in screening protocols for BCVI.

In BCVI it is well established that those with symptomatic lesions should undergo further management. This includes those with persistent arterial bleeding from the neck, expanding hematomas, bruits, and those with mental status changes or ischemic changes on CT scan not explained by direct neurologic injury. However, screening of asymptomatic patients is much more controversial. The most commonly cited screening protocol came out of Denver (1), with a modification based on improved data in 2004 (2). In comparison, the protocol utilized at VGH is more aggressive than what has been published, while screening at Cook County is less so. It is important to remember that these protocols are based on limited Level II and Level III evidence, making a universal protocol impossible to endorse. This is also the primary reason why Cook County has avoided implementing formal, protocol-driven recommendations for screening of BCVI. The EAST guidelines recommendations (Level III) are also listed below for comparison (3).

VGH	Cook County	Modified Denver Criteria	EAST Guidelines
GCS<13	altered mental status not explained by CT findings	GCS<6 (DAI)	GCS <9 (DAI)
Basilar skull fracture		Basilar skull fracture	Petrous bone fracture
C spine body fracture		C spine fracture	C spine # (C1-3 OR through foramen transversarium OR with subluxation/rotation)
LeFort fracture	Bilateral mandible fracture	LeFort II or III fracture	LeFort II or III fracture
Major thoracic injury	Direct blow to anterior neck	Near hanging injury

Another controversial issue is the ideal screening test for BCVI. At VGH we use high quality CTA from arch to apex, a protocol similar to that reported out of Memphis (4). Cook County, on the other hand, recommends formal angiography, which is in keeping with the protocols endorsed by EAST and the Denver group. There is some controversy in this regard as well, as studies have produced conflicting data. Still, CTA is easier to acquire at most centers and associated with less risk of complications, which is why it is preferred at our center where we screen a large proportion of our trauma patients. It should be noted, however, that formal angiography remains the gold standard for diagnosis of these injuries.

Both protocols are based on different interpretations of the same literature. Admittedly, the evidence is limited. Protocols are influenced by institutional resources, history, and culture. It only takes one or two bad outcomes (particularly in young, seemingly minimally injured patients) to produce a change in practice. It is crucial for us to constantly re-evaluate our practice patterns, particularly as new evidence emerges.

For completeness, here is an overview of the treatment of BCVI:

The injuries are typically graded as follows (2):

I. dissection of <25% circumference

II. dissection of >25% circumference

III. pseudoaneurysm

IV. thrombosis

V. transection

Grade V injuries typically require operative intervention. If inaccessible, angio-embolization can be considered. For grade I-IV injuries the mainstay of treatment is anticoagulation, with increasing success rates with lower grades of injury. There is considerable debate as to whether antiplatelet (ASA or clopidogrel) or heparin/warfarin anticoagulation is superior. However, generally if the patient does not have a contraindication heparin infusion bridged to warfarin therapy should be considered for a total of 3-6 months. Grade III or IV injuries should also be considered for early operative management due to high failure rates of anticoagulation. The role of endovascular stenting is not well defined at this time. Many authors recommend follow-up imaging, typically after 7-10 days.

References:

1. Biffl WL, Moore EE, Offner PJ et al. Optimizing screening for blunt cerebrovascular injuries. Am J Surg 1999;178:517-522.

2. Cothren CC, Moore EE, Biffl WL et al. Anticoagulation is the gold standard therapy for blunt carotid injuries to reduce stroke rate. Arch Surg 2004;139:540-546.

3. Bromberg WJ, Collier BC, Diebel LN et al. EAST guidelines: blunt cerebrovascular injury. J Trauma 2010;68(2):471-477.

4. Fabian TC. Blunt cerebrovascular injuries: Anatomic and pathologic heterogeneity create management enigmas. J Am Coll Surg 2013;216(5):873-885.

from:

Brett Mador, MD

General Surgery PGY-4

UBC, Vancouver, Canada