What is the management of blunt vertebral artery injuries diagnosed using the Denver criteria?

Denver Criteria for Blunt Vertebral Artery Injuries: Screening and Management

Initial Screening Approach

When blunt trauma patients meet the expanded Denver criteria for blunt cerebrovascular injury (BCVI), they should undergo CT angiography (CTA) of the head and neck with IV contrast as the primary screening modality. 1

The expanded Denver criteria demonstrate excellent negative predictive value and high sensitivity as a screening tool for BCVI, making them the standard approach for identifying patients who require vascular imaging. 1

Specific Denver Criteria Components

Signs/Symptoms requiring immediate CTA:

• Potential arterial hemorrhage from neck/face 1
• Cervical bruit in patients <50 years of age 1
• Expanding cervical hematoma 1
• Focal neurologic deficit (TIA, hemiparesis, vertebrobasilar symptoms, Horner syndrome) 1
• Neurologic deficit inconsistent with head CT findings 1
• Infarct on CT or MRI 1

Risk Factors requiring CTA screening:

• High-energy transfer mechanism with displaced LeFort II or III midface fracture 1
• Complex skull fracture/basilar skull fracture/occipital condyle fracture 1
• Traumatic brain injury with GCS <6 1
• Cervical spine subluxation/dislocation 1
• Cervical spine fractures at C1-3 or involving the transverse foramen at any level 1
• Scalp degloving 1
• Thoracic vascular injuries 1
• Upper rib fractures 1

Imaging Protocol

CTA head and neck with IV contrast is recommended over digital subtraction angiography for initial vascular evaluation because of its short acquisition time, low complication rate, and ability to detect almost all clinically relevant blunt cervical arterial injuries. 1

MRA is considered equivalent to CTA for BCVI detection and can be used as an alternative, though it distinguishes almost all but not necessarily all clinically significant cervical arterial injuries. 1

Critical Caveat About Screening Performance

The expanded Denver criteria have a documented false-negative rate of 16% to 17.5% for blunt cerebrovascular injury, meaning they miss a significant proportion of injuries. 1 Recent evidence suggests that universal screening with CTA for all blunt trauma patients may be superior to selective screening based on Denver criteria, as the diagnostic performance of these clinical criteria is actually poor with sensitivities ranging from only 47.3% to 74.7%. 2

Management Based on Denver Grading Scale

Once vertebral artery injury is identified, treatment is stratified by Denver grade:

Grade I injuries (intimal irregularity/dissection with <25% luminal narrowing):

• Medical therapy with aspirin is the most common approach (66% of patients in one series) 3
• Natural course is typically benign with 96% not worsening and 62% showing complete radiographic resolution 3
• Median time to resolution is 7 days 3

Grade II injuries (dissection/intramural hematoma with ≥25% luminal narrowing):

• Similar management to Grade I with aspirin or anticoagulation 3
• 96% do not worsen, with median time to resolution of 8 days 3

Grade III injuries (pseudoaneurysm):

• Typically managed medically with antiplatelet or anticoagulation therapy 3

Grade IV injuries (occlusion):

• Medical management is standard 3
• These injuries tend to persist, with 75.9% remaining unchanged on follow-up imaging 3

Grade V injuries (transection with free extravasation):

• May require endovascular intervention with coil embolization 3

Antithrombotic Therapy Specifics

In clinical practice, treatment options include:

• Aspirin monotherapy (used in 66% of cases) 3
• Systemic anticoagulation with heparin drip (22% of cases) 3
• Therapeutic enoxaparin (1% of cases) 3

Neither delay in medical treatment nor choice of antithrombotic agent has shown significant impact on outcomes in vertebral artery injuries. 3

Follow-Up Imaging Recommendations

Routine serial imaging for Grade I and II blunt vertebral artery injuries is not warranted, as only 3.7% of these injuries worsen and none result in clinical sequelae. 3 Most follow-up scans for Grade I and II injuries occur within 50 days when performed. 3

For Grade IV injuries that persist in 75.9% of cases, selective follow-up imaging may be considered based on clinical symptoms. 3

Clinical Outcomes and Prognosis

Posterior circulation stroke due to blunt vertebral artery injury is rare, with only one symptomatic injury manifesting as cerebellar ischemic infarct in a series of 141 patients. 3 The overall 30-day mortality for patients with vertebral artery injuries is 9.9%, though this is primarily driven by associated injuries (mean ISS of 22). 3

The incidence of vertebral artery injury in blunt trauma patients is approximately 1.1% of all trauma admissions. 3 Among those screened with CTA, the detection rate is 7.6-8.3%. 2, 4

Important Clinical Pitfall

Skull-base fracture is the strongest traumatic risk factor for BCVI (OR 3.61), and its presence should trigger aggressive screening even if other Denver criteria are not met. 5 Additionally, 79.4% of vertebral artery injuries have associated cervical fractures, most commonly at C6 and C7 levels. 3

The most common injury locations are V2 segment (47.5%) and V3 segment (39.7%). 3