The levels of recommendation (1-3) and classes of evidence (I-III) are defined at the end of the "Major Recommendations" field.
What patients should be screened for blunt cerebrovascular injury (BCVI)?
Level 1
No Level 1 recommendations can be made.
Level 2
- Patients presenting with any neurologic abnormality that is unexplained by a diagnosed injury should be evaluated for BCVI.
- Blunt trauma patients presenting with epistaxis from a suspected arterial source following trauma should be evaluated for BCVI.
Level 3
- Asymptomatic patients with significant blunt head trauma as defined below are at significantly increased risk for BCVI and screening should be considered.
Risk factors:
- Glasgow Coma Scale (GCS) ≤8
- Petrous bone fracture
- Diffuse axonal injury
- Cervical spine fracture
- Fracture through the foramen transversum
- Lefort II or III facial fractures
- Pediatric trauma patients should be evaluated using the same criteria as the adult population.
Question addressed: What is the appropriate modality for the screening and diagnosis of BCVI?
Level 1
No Level 1 recommendations can be made.
Level 2
- Diagnostic four vessel cerebral angiography (FVCA) remains the gold standard for the diagnosis of BCVI.
- Duplex ultrasound is not adequate for screening for BCVI.
- Computed tomography angiography (CTA) with a 4 (or less)-slice multidetector array is neither sensitive nor specific enough for screening for BCVI.
Level 3
- Multi-slice (8 or greater) multidetector CTA has the same rate of detection for BCVI when compared to historic control rates of diagnosis with FVCA and should be considered as a screening modality in place of FVCA.
How should BCVI be treated? This references a grading scheme proposed by Biffl et al., 1999.
Grading scale
Grade I – Intimal irregularity with <25% narrowing
Grade II – Dissection or intramural hematoma with >25% narrowing
Grade III – Pseudoaneurysm
Grade IV – Occlusion
Grade V – Transection with extravasation
Level 1
No Level 1 recommendations can be made.
Level 2
- Barring contraindications, Grade I and II injuries should be treated with antithrombotic agents such as aspirin or heparin.
Level 3
- Either heparin or antiplatelet therapy can be used with seemingly equivalent results. A number of authors still recommend heparinization if there is no contraindication, reserving anti-platelet agents for those patients with relative contraindications to heparinization.
- If heparin is selected for treatment, the infusion should be started without a bolus and titrated to an activated partial thromboplastin time (aPTT) of 50 to 60 sec.
- In patients in whom anticoagulant therapy is chosen conversion to warfarin titrated to a Prothrombin Time, International Normalized Ratio (PT INR) of 2 to 3 for 3 to 6 months is recommended.
- Grade III injuries (pseudoaneurysm) rarely resolve with observation or heparinization and invasive therapy (surgery or angio-interventional) should be considered. N.B. carotid stents placed without subsequent anti-platelet therapy have been noted to have a high rate of thrombosis in this population. (Cothren et al, 2005)
- In patients with an early neurologic deficit and an accessible carotid lesion operative or interventional repair should be considered to restore flow.
- In children who have suffered an ischemic neurologic event, aggressive management of resulting intracranial hypertension up to and including resection of ischemic brain tissue has improved outcome as compared to adults and should be considered for supportive management.
For how long should antithrombotic therapy be administered?
No recommendations can be made for this question.
How should one monitor the response to therapy?
Level 1
No Level 1 recommendation can be made.
Level 2
- Follow-up angiography is recommended in Grade I-III injuries. In order to reduce the incidence of angiography-related complications this should be performed after 7 days post injury.
Level 3
There are no Level 3 guidelines for this question.
Definitions:
Classes of Evidence
Class I: Prospective, randomized, controlled trial
Class II: Clinical studies in which the data was collected prospectively, and retrospective analyses which were based on clearly reliable data. Types of studies so classified include: observational studies, cohort studies, prevalence studies, and case control studies.
Class III: Studies based on retrospectively collected data. Evidence used in this class includes clinical series, database or registry reviews, large series of case reviews, and expert opinion.
Levels of Recommendations
Level 1: The recommendation is convincingly justifiable based on the available scientific information alone. This recommendation is usually based on Class I data, however strong Class II evidence may form the basis for a Level 1 recommendation, especially if the issue does not lend itself to testing in a randomized format. Conversely, low quality or contradictory Class I data may not be able to support a Level 1 recommendation.
Level 2: The recommendation is reasonably justifiable by available scientific evidence and strongly supported by expert opinion. This recommendation is usually supported by Class II data or a preponderance of Class III evidence.
Level 3: The recommendation is supported by available data but adequate scientific evidence is lacking. This recommendation is generally supported by Class III data. This type of recommendation is useful for educational purposes and in guiding future clinical research.
