The pathophysiology of extracranial traumatic aneurysm formation has not been fully elucidated. Intraarterial optical coherence tomography (OCT), an imaging modality capable of micrometer cross-sectional resolution, was used to evaluate patients presenting with saccular traumatic aneurysms of the internal carotid artery (ICA). Two consecutive trauma patients diagnosed with saccular traumatic aneurysms of the cervical ICA, per the institutional screening protocol for traumatic cerebrovascular injury, underwent digital subtraction angiography (DSA) with OCT. Optical coherence tomography demonstrated disruption of the intima with preservation and stretching of the more peripheral layers. In 1 patient the traumatic aneurysm was associated with thrombus formation and a separate, more proximal dissection not visible on CT angiography (CTA) or DSA. Imaging with OCT indicates that saccular traumatic aneurysms may develop from disruption of the intima with at least partial preservation of the media and adventitia. This provides in vivo evidence that saccular traumatic aneurysms result from a partial arterial wall tear rather than complete disruption. Interestingly, OCT was also able to detect arterial injury and thrombi not visible on CTA or DSA.
Christoph J. Griessenauer, Paul M. Foreman, John P. Deveikis and Mark R. Harrigan
Paul M. Foreman, Alejandro Enriquez-Marulanda, James H. Mooney, Philip G. R. Schmalz, Christoph J. Griessenauer, John P. Deveikis and Mark R. Harrigan
Dual antiplatelet therapy is required for the treatment of intracranial aneurysms with the Pipeline embolization device (PED). Platelet function testing (PFT) is often used to assess the efficacy of the antiplatelet regimen prior to PED placement. The optimal impedance values for whole blood aggregometry in this setting have not been defined.
A retrospective review of a prospectively maintained database was performed for the years 2011–2015 to identify patients with intracranial aneurysms treated with the PED who underwent pretreatment PFT using whole blood aggregometry. Antiplatelet therapy was not altered based on PFT results; all patients remained on standard doses of aspirin and clopidogrel. Clinical, radiographic, and laboratory data were analyzed to identify the optimal cutoff impedance value for clopidogrel responsiveness using the receiver operating characteristic curve and Youden’s index.
Forty-nine patients underwent 53 endovascular procedures for the treatment of 76 aneurysms using the PED. The majority of these aneurysms were located in the anterior circulation (90.8%) and affected the internal carotid artery (89.5%). Patients in 30 procedures (56.6%) were identified as clopidogrel responders based on the manufacturer cutoff value (< 6 Ω). Thromboembolic complications occurred in 13 (24.5%) procedures; patients in 6 (11.3%) cases were symptomatic and those in 3 (5.7%) cases had ischemic strokes. Eleven of the 13 (84.6%) thromboembolic complications occurred in clopidogrel nonresponders. An impedance value of ≥ 6 Ω was independently associated with thromboembolic complications. The optimal electrical impedance value was identified as ≥ 6 Ω (sensitivity 84.6%, specificity 70.0%, area under the curve 0.77) for identifying clopidogrel nonresponders.
Thromboembolic complications are more common following PED placement in patients who do not respond adequately to clopidogrel. Clopidogrel nonresponders can be identified using pretreatment whole blood aggregometry. The optimal cutoff value to categorize a patient as a clopidogrel nonresponder when using whole blood aggregometry is ≥ 6 Ω.
Paul M. Foreman, Christoph J. Griessenauer, Kimberly P. Kicielinski, Philip G. R. Schmalz, Brandon G. Rocque, Matthew R. Fusco, Joseph C. Sullivan III, John P. Deveikis and Mark R. Harrigan
Blunt traumatic cerebrovascular injury (TCVI) represents structural injury to a vessel due to high-energy trauma. The Biffl Scale is a widely accepted grading scheme for these injuries that was developed using digital subtraction angiography. In recent years, screening CT angiography (CTA) has been used to identify patients with TCVI. The reliability of this scale, with injuries assessed using CTA, has not yet been determined.
Seven independent raters, including 2 neurosurgeons, 2 neuroradiologists, 2 neurosurgical residents, and 1 neurosurgical vascular fellow, independently reviewed each presenting CTA of the neck performed in 40 patients with confirmed TCVI and assigned a Biffl grade. Ten images were repeated to assess intrarater reliability, for a total of 50 CTAs. Fleiss' multirater kappa (κ) and interclass correlation were calculated as a measure of interrater reliability. Weighted Cohen's κ was used to assess intrarater reliability.
Fleiss' multirater κ was 0.65 (95% CI 0.61–0.69), indicating substantial agreement as to the Biffl grade assignment among the 7 raters. Interclass correlation was 0.82, demonstrating excellent agreement among the raters. Intrarater reliability was perfect (weighted Cohen's κ = 1) in 2 raters, and near perfect (weighted Cohen's κ > 0.8) in the remaining 5 raters.
Grading of TCVI with CTA using the Biffl Scale is reliable.