Navigating Twists, Turns and Tears: BCVI in the ED (Part 2)

Blunt cerebrovascular injury (BCVI) involves vessel injuries that occur from trauma mechanisms commonly seen in the emergency department: falls down stairs, motor vehicle collisions, and facial trauma. By identifying high-risk patients early, we can decrease the risk of stroke by up to 15% with the use of aspirin.

In part 1 we explored the physiology, mechanism of injury, and presented a few cases to consider; check it out here. 

Screening for BCVI

Formal screening criteria can help guide when to consider blunt cerebrovascular injury (BCVI) in patients with blunt trauma.

Current trauma guidelines—including those from ATLS, WEST, and EAST—recommend screening both symptomatic and asymptomatic high-risk trauma patients for BCVI. The concept of screening asymptomatic individuals was first proposed in the 1990s, after studies revealed the high morbidity and mortality associated with missed BCVI diagnoses.

One landmark study during this time, led by Biffl and colleagues at a regional trauma center, introduced formal screening protocols for BCVI. Their implementation resulted in an eight-fold increase in detection rates. These findings have since been replicated across multiple trauma centers.

Over the past two decades, several institutions have developed their own screening tools to improve detection of BCVI in at-risk patients. These include the Denver, Memphis, and Boston criteria.

The Denver screening criteria—originally developed by Dr. Biffl in 1994—were updated in 2010 and again in 2012. The current iteration, known as the expanded Denver criteria, now includes additional risk factors such as mandibular fractures, complex skull base fractures, and traumatic brain injury with associated thoracic trauma.

Expanded Denver Criteria (Burlew et al. 2012)45

Expanding the screening criteria was shown in to improve BCVI detection from 2.4% to 4.0% ^46,47. The expanded Denver protocol has been externally validated, and shown to have a sensitivity of just 83%, and a specificity of 51% ⁴⁸. The expanded Denver criteria has been the most used criteria in practice, and is included in the most recent trauma guidelines for BCVI⁶.

But, the literature still conflicts on the best screening method, given the lower sensitivity of Denver. Other studies have looked at more liberalized protocols, because even with our best current expanded screening, studies show that a real proportion of BCVI are missed ^49,50.

Universal Imaging

Universal imaging for blunt traumas means including the CTA with the pan-trauma scans. This is a topical issue for trauma activations, particularly in the past 5 years. In one large study from the US supporting the role of universal imaging, 4659 blunt traսma activations underwent a screening CTA. Of these patients with BCVI, 17% would not have been identified by expanded screening criteria⁵¹.

Missing any BCVI can result in significant morbidity and mortality. Many trauma centers in Canada and the US have embraced universal imaging for this reason⁵⁰. But it has yet to be incorporated into major trauma guidelines.

Universal imaging has consistently been shown to increase the detection of BCVI. Several studies report that this approach identifies more low-grade injuries and equivocal vascular irregularities in particular. While the clinical relevance of these low-grade lesions was once debated, we now understand—based on prior data—that the risk of stroke increases with injury severity, but is not negligible even in lower-grade injuries.

This raised an important question: Are we detecting clinically meaningful lesions with universal imaging, or simply artifacts?

A 2024 review by Tran et al. supported that universal imaging protocols do result in higher detection rates, especially for low-grade BCVI. Notably, however, the incidence of stroke per case remained consistent—suggesting these low-grade injuries may, in fact, be clinically significant. If they were merely artifacts, we would expect the stroke rate to decline as more were identified.

So, what level of stroke risk would prompt you to treat a grade I BCVI? Would 1%, 2%, or 3% concern you?According to a multicenter study published by the EAST group in 2023, the stroke rate for grade I internal carotid artery (ICA) BCVI was 5.5%. That risk is low—but certainly not negligible.

As a result, many trauma centers across the U.S. and Canada have adopted universal imaging protocols. Local practice experts confirm that even lower-grade lesions are managed and followed, given the potential for stroke or progression.

CT Angiography

Another consideration is the accuracy of CTA. In particular, mild lumen irregularities can be difficult to distinguish from grade I lesions. The specificity of CTA in diagnosing low-grade BCVI is generally high and has increased over time with more advanced CT scanners and neuroradiology expertise. But it is not 100%. One retrospective review reported a PPV of СΤA of 30% for grade I iոjuries, and 97% for grade IV⁵³. According to local practice experts, the equivocal findings are managed in a similar way as a grade I BCVI, given the risk of stroke, and given the safety profile of treatment. We’ll discuss management more later.

ED Screening for BCVI

Universal imaging has primarily been studied in trauma activations—patients with higher Injury Severity Scores. But in the Emergency Department, we see a broader spectrum of blunt trauma, much of which doesn’t meet activation criteria.

Blunt cerebrovascular injuries aren’t limited to critically ill trauma code patients. As highlighted in earlier cases, many blunt trauma patients we routinely assess in the ED may still be at high risk for BCVI—and these injuries are likely underrecognized.

The challenge lies in the diversity of blunt trauma presentations we encounter, ranging from simple ground-level falls to high-speed motor vehicle collisions. Deciding when to investigate for BCVI in this broad population is far from straightforward.

A universal, shotgun-style imaging approach for all blunt trauma is simply not feasible. Relying on mechanism alone to trigger CT angiography would overwhelm resources and expose patients to unnecessary imaging. What we need is a practical, evidence-informed pathway to guide decision-making.

After speaking with local practice experts and reviewing the literature, the consensus is to use an expanded screening approach. Most BCVI studies focus on trauma activation populations, so we’ve adapted those findings to create a more applicable framework for everyday ED practice.

When to consider BCVI in the ED:

1. Consider the mechanism based on history. High-risk mechanisms include:
   
   • Direct force and compression to the neck (strangulation, assault, seatbelt injury)
   • Hyperextension of the neck (such as a hanging or diving injury)
   • *High-speed motor vehicle or bike collisions
   • *Significant falls – for example down stairs, or from a significant height >3m
   • *With suspicison for head, face, neck, or thorax injury

      

2. Next, assess if the physical exam showing signs of a possible high-risk injury:
   • Severe facial trauma
   • Midface deformity
   • Bite malocclusion or jaw deformity
   • Clear cervical spine deformity or +tenderness
   • Signs of basilar skull fractures
   • Neck swelling or bruising

     Remember our previous case of the assaulted patient- he had swelling and deformity to his face, jaw and periorbital regions, as well as abrasions and bruising to his neck. A possible midface and/ or mandibular fracture as well as neck trauma is suspected. Given this patient has a historical mechanism and high-risk physical exam features- a CTA should be added on with the other initial trauma scans to assess for BCVI.

     
     The patient’s CT scans show a Lefort II fracture and SAH, and his CTA show a grade II BCVI of the left internal carotid artery.
     

     If clinical signs are present on your initial exam, add the CTA with your initial CT imaging

3. Consider initial CT findings of associated high-risk injuries:
   • Lefort II or III
   • Cervical spine fracture, subluxation or dislocation
     • Transverse foramen fracture, C1-C3 fractures, two level fractures, and subluxations or dislocations
   • Mandible fracture
   • Basilar skull fracture
   • Upper rib fractures
   • Thoracic and head trauma. Thoracic trauma includes flail chest, pulmonary contusions, multiple rib fractures, and thoracic spine burst fracture

     

Case 3- Ms Spine

Now for the third and final case: you see a 70-year-old woman in the ED who tripped and fell backwards down 8 stairs. She’s a GCS 14, with a hematoma to her occipital region and right mid-back tenderness. There are no other identified injuries.

She doesn’t meet our criteria for historical mechanism with high-risk exam features. A CT head, c-spine and CT chest are ordered, which show a fracture along her petrous bone (skull base) extending to the foramen magnum, a small SDH, and 2 ribs fractures.

This patient has a CT finding of an associated high-risk injury. She needs to go back for CTA to assess for BCVI. This can occur while simultaneously planning for the patient’s ultimate disposition. The patient goes back for CTA while you discuss with the admitting service. This shows a BCVI grade I injury to the right vertebral artery.

These patients are most often consulted to trauma or another service. They will likely ultimately get CTA once further assessed by the trauma team. Given the valuable time window discussed previously, however, it’s important in the ED to consider BCVI early, and to initiate work-up. Recall, most strokes related to BCVI occur between 12-72 hours ^11,31,32,33. Any ‘early’ stroke can have significant consequences, especially in a younger trauma patient.

Take Home Points

ED approach for when to work-up a possible BCVI:

Management

With screening criteria and imaging, high risk blunt trauma patients and asymptomatic BCVI can be identified, and treatment started. Multiple retrospective studies have reported fewer ischemic neurologic events in asymptomatic patients with BCVI who are started on antithrombotic therapy (ATT) ^1,42,54-56.

This is corroborated by a retrospective analysis of the PROOVIT trauma multicenter registry in 2021. They identified 970 BCVIs and found that ATT compared to no treatment was associated with lower stroke rates (6.1% versus 16.3%) and mortality (5.6% versus 37.6) ³.

A systematic review and meta analysis in 2021 reviewed 19 of these retrospective studies that reported treatment effects for asymptomatic BCVI. Patients without treatment had an overall stroke rate of 25% compared with antiplatelets at 8% and anticoagulation at 7% ¹. It is important to note that there are no prospective trials to guide management.

BCVI Management

The mainstay of preventative treatment for asymptomatic BCVI is ATT. The most recent BCVI trauma clinical practice guidelines recommend ATT ^7,35, and to initiate ATT as early as possible to prevent stroke and reduce mortality ^6,39.

ATTs include systemic anticoagulation (heparin) or antiplatelets (aspirin). There are no RCTs directly comparing anticoagulation with antiplatelet therapy. Treatment guidelines largely come from retrospective case series and strategies used in the management of CeAD, with smaller sample sizes ^1,2,54.

A meta-analysis in 2021 by Ku et al.⁵⁴ of 2044 from 22 studies found that both antiplatelet (aspirin) and anticoagulant (heparin) therapies are similarly effective in preventing ischemic stroke in BCVI patients compared to the untreated group (2.4% versus 2.2% versus 20%, respectively). Antiplatelet therapy, however, was found to be associated with a lower risk of hemorrhagic complications compared to anticoagulation (2 vs 6%; OR 0.38, 95% CI 0.15-1.00)⁵⁴. This suggests that antiplatelet therapy may be preferred in the trauma population, but randomized trials are needed to confirm this.

According to local practice experts, aspirin is the antithrombotic agent used in practice, particularly for lower grade lesions. Notably, there is practice variability with respect to dose. Higher grade BCVIs, particularly grade III, may be managed with endovascular stenting ^46,47. Management of these injuries is led by the neurovascular and trauma teams, and is a multidisciplinary decision.

Back to the case of the cyclist hit by the car. Her CTA showed a grade I BCVI of the right ICA. She is admitted to the trauma service and started on ASA 81mg for stroke prevention.

ATT and Associated Injuries

ATT for BCVI may be contraindicated in patients with certain traumatic injuries (e.g. traumatic brain injury), at least temporarily. The timing of when to start treatment in these cases is variable, and done in close consultation with the relevant surgical team. For other injuries, such as solid organ injuries, early treatment with ASA is often safe once bleeding is controlled. This has been confirmed by several studies⁵⁷.

Follow-up and Monitoring

Current trauma guidelines ^6,7,35 suggest follow-up with a repeat CT angiogram typically 7-10 days after the initial injury (same). Repeat imaging is done to assess for healing versus progression of the BCVI, and to guide ATT duration and further treatment. If the injury has healed, ATT is likely discontinued, whereas if the injury has not healed or has progressed, therapy is continued and additional treatments such as endovascular stenting may be considered ¹⁰.

In terms of injury progression, BCVI has been shown to be a dynamic injury⁵⁸. Injury evolution is largely dependent on the initial injury grade, however all grades of BCVI lesions can progress to more significant injuries³². In one review done at a level 1 trauma center, 1204 patients treated for BCVI were followed over a 10-year period. They found that low grade lesions were more likely to resolve, but still had a 5% progression rate by 180 days. High grade lesions were more likely to progress, with a 19% progression rate⁵⁸.

The dynamic nature of BCVIs provides further support for the importance of timely diagnosis. From a clinical perspective, this was corroborated by local practice experts; in some cases, even lower grade BCVI can progress.

Altogether, the specific ATT dosage, duration of treatment and follow-up protocol depend on a variety of factors, including the degree of injury, the patient’s bleeding risk, the hospital site and the specialty involved ^58,10. For many centers, treatment involves daily aspirin 81mg, repeat imaging at 7-10 days, and outpatient follow-up weeks to months after the initial injury.

Take-Home Points:

• Treatment with daily aspirin can reduce the risk of stroke with BCVI
• A point to be mindful of- the studies on BCVI stroke risk and mortality with ATT are retrospective and generally have a smaller sample size
• ATT, however, has been consistently associated with a lower incidence of stroke in BCVI, a trend shown in numerous reviews over the past 20-30 years ^1,42,54-56.
• We can contribute to this important treatment effect by identifying these injuries early.

Other Interventions

For BCVI, the nature of symptoms and specific grade of injury can dictate the need for other interventions. These can include endovascular therapy and surgery. Endovascular therapy for BCVI is generally reserved for specific cases of more significant, higher-grade injuries, such as large or enlarging pseudoaneurysms, symptomatic pseudoaneurysms or significant arterial stenosis⁵⁹.

Final Take-Home Points:

• BCVI ED checklist and algorithm – consider the historical mechanism, clinical exam signs of high-risk injuries, and CT findings of a high-risk injury.
• Blunt traumas that have a high risk for BCVI are seen and managed in the ED. So consider following this or some type of liberalized screening guideline in the ED to help identify potentially significant lesions.
• There is a critical time period in BCVI between the blunt trauma and the onset of stroke. We want to target this time window for BCVI identification.
• BCVI exists on a spectrum: from occult lesions to complete vessel occlusion. Identification of these injuries allows for early initiation of treatment in order to reduce the risk of potentially significant stroke events.