Morphological characteristics of symptomatic and asymptomatic carotid webs.

OBJECTIVE: Carotid webs (CWs) are an increasingly recognized source of recurrent stroke among young patients without conventional vascular risk factors. There have been no previous studies demonstrating that specific web morphological characteristics correlate with a higher stroke risk. The authors aim to report distinct morphological features of symptomatic and asymptomatic CWs. METHODS: The authors performed a cross-sectional study of patients with CWs detected on CT angiography (CTA) of the neck. Patients were categorized based on whether or not they presented with stroke ipsilaterally and if it was likely to be attributable to their web. The following CW morphological variables were recorded and compared based on CTA: length, thickness, angle, and the proportion of carotid bulb lumen occupied by the web (web-to-bulb ratio [WBR]). RESULTS: A total of 86 CWs were identified, 14 of which presented with stroke (16.3%). Patients presenting with stroke had webs that were significantly longer (4.18 mm vs 2.20 mm, p = 0.001) and were situated at more acute angles relative to the carotid wall (73.2° vs 94.9°, p = 0.004). Additionally, patients presenting with stroke had higher WBRs compared to the asymptomatic cohort (0.50 vs 0.36, p = 0.008). The optimal threshold associated with stroke was web length ≥ 3.1 mm (OR 15.2, 95% CI 3.73-61.8; p < 0.001), web angle ≤ 90.1° (OR 5.00, 95% CI 1.42-17.6; p = 0.012), and WBR ≥ 0.50 (OR 30.0, 95% CI 5.94-151; p < 0.001). CONCLUSIONS: Patients with CWs that occupy more than half of the diameter of the carotid bulb lumen and are situated at acute angles relative to the carotid wall are more likely to present with acute ischemic stroke. Additional studies are needed to determine the long-term outcomes of these lesions.

Imaging analysis of ischemic strokes due to blunt cerebrovascular injury.

BACKGROUND: The timing of stroke onset among patients with blunt cerebrovascular injury (BCVI) is not well understood. All blunt trauma patients at our institution undergo a screening computed tomographic angiography (CTA) of the neck. Most patients with CTA evidence of BCVI are treated with aspirin, and all patients with clinical evidence of stroke are treated with aspirin and undergo magnetic resonance imaging (MRI) of the brain. We conducted a retrospective review to determine the incidence of stroke upon admission and following admission. METHODS: All neck CTAs and head MRIs obtained in blunt trauma patients were reviewed from August 2017 to August 2019. All CTAs that were interpreted as showing BCVI were individually reviewed to confirm the diagnosis of BCVI. Stroke was defined as brain MRI evidence of new ischemic lesions, and each MRI was reviewed to identify the brain territory affected. We extracted the time to aspirin administration and the timing of stroke onset from patients' electronic health records. RESULTS: Of the 6,849 blunt trauma patients, 479 (7.0%) had BCVIs. Twenty-four patients (5.0%) with BCVI had a stroke on admission. Twelve (2.6%) of the remaining 455 patients subsequently had a stroke during their hospitalization. The incidence of stroke among patients with BCVI was 7.5%; 2.6% were potentially preventable. Only 5 of the 12 patients received aspirin before the onset of stroke symptoms. All 36 patients with BCVI and stroke had thromboembolic lesions in the territory supplied by an injured vessel. CONCLUSION: With universal screening, CTA evidence of BCVI is common among blunt trauma patients. Although acute stroke is also relatively common in this population, two thirds of strokes are already evident on admission. One third of BCVI-related strokes occur after admission and often relatively early, necessitating rapid commencement of preventative treatment. Further studies are required to demonstrate the value of antithrombotic administration in preventing stroke in BCVI patients. LEVEL OF EVIDENCE: Prognostic and Epidemiologic; Level IV.

Incidentally discovered dural arteriovenous fistula during middle meningeal artery embolization for the treatment of chronic subdural hematoma.

BACKGROUND: The incidence of chronic subdural hematoma (CSDH) is increasing with population age and anticoagulant use. Embolization of the middle meningeal artery (MMA) is an emerging, less invasive alternative to open surgery in treating this condition. Dural arteriovenous fistula (DAVF) is a rare condition whose association with CSDH is not well understood. We present three cases with incidentally discovered DAVFs during MMA embolization for the treatment of CSDH that necessitated adjustments to initial treatment strategy. CASE DESCRIPTIONS: We retrospectively reviewed all MMA embolizations performed for the treatment of CSDH beginning in 9/2019 to 11/2020. Imaging and hospital course of three cases of incidentally discovered DAVF, including patient demographics, clinical presentation, methods of treatment, imaging and outcome were assessed. Thirty MMA embolizations were performed as primary or adjunct treatment of CSDH. DAVF was discovered angiographically in 3 (10%) cases. All patients reported a history of prior closed head injury, although the timing of injury and subdural blood product age did not correlate in 2 of the 3 cases. All subjects experienced complete symptomatic and radiographic resolution of the subdural hematoma and DAVF following intervention. CONCLUSION: As MMA embolization for CSDH becomes more frequent, so may the incidental diagnosis of DAVF. Awareness of this potential association is critical to diagnosing DAVF with angiography and altering treatment strategies as needed.

Universal screening for blunt cerebrovascular injury.

BACKGROUND: Blunt cerebrovascular injury (BCVI) can result in thromboembolic stroke. Many trauma centers selectively screen patients with cervical computed tomographic angiography (CTA) based on clinical criteria. In 2016, our institution adopted universal screening for BCVI for all blunt trauma patients. The aim of this study was to accurately determine the incidence of BCVI and to evaluate the diagnostic performance of the Denver criteria (DC), expanded Denver criteria (eDC), and Memphis criteria (MC) in selecting patients for screening. METHODS: Retrospective cohort study of adult (≥16 years) blunt trauma patients who presented to the Level I trauma center at University of Alabama at Birmingham. We reviewed all CTA reports and selected CTA images to obtain the true incidence rate of BCVI. We then evaluated the diagnostic performance of the DC, eDC, and MC. RESULTS: A total of 6,800 patients who had suffered blunt trauma were evaluated, of whom 6,287 (92.5%) had a neck CTA. Of these, 480 (7.6%) patients had CTA evidence of BCVI. The eDC identified the most BCVI cases (sensitivity 74.7%) but had the lowest positive predictive value (14.6%). The DC and MC had slightly greater positive predictive values (19.6% and 20.6%, respectively) and had the highest diagnostic ability in terms of likelihood ratio (2.8 and 2.9) but had low sensitivity (57.5% and 47.3%). Consequently, if relying on the traditional screening criteria, the DC, eDC, and MC would have respectively resulted in 42.5%, 25.3%, and 52.7% of patients with BCVI identified by universal screening not receiving a neck CTA to screen for BCVI. CONCLUSION: Blunt cerebrovascular injury is even more common than previously thought. The diagnostic performance of selective clinical screening criteria is poor. Consideration should be given to the implementation of universal screening for BCVI using neck CTA in all blunt trauma patients. LEVEL OF EVIDENCE: Diagnostic, level III.