Background: In vitro models have suggested that stents affect atherosclerotic plaques symmetrically because of their outward radial forces. We evaluated the effects of stents on carotid plaque and the arterial wall using carotid ultrasound in carotid stenting patients to see whether these effects were borne out in vivo. Methods: From a carotid stent database, 30 consecutive patients were selected. All had carotid Doppler ultrasound performed pre- and poststenting. The diameters of the lumen at the level of stenotic plaque pre- and poststenting, the dorsal and ventral plaque thickness, and of the outer arterial wall diameter were measured. Plaque thickness was measured at the level of maximal stenosis. Nonparametric tests were used to determine whether the stent effect and luminal enlargement were based on wall remodeling or on total arterial expansion. Results: The patients were followed for an average of 22 months. Eighteen patients were male, with an average age of 70 years. A total of 87% of patients were symptomatic ipsilateral to the side of stenosis. Nine patients had angioplasty intraprocedurally. The luminal diameter increased poststenting in the region of severe stenosis. Plaque thickness, both ventrally and dorsally, decreased poststenting, with no significant difference between the ventral and dorsal plaque effects. The outer arterial wall diameters did not change. The measured lumen in the stent increased over time poststenting. Conclusions: Self-expanding nitinol stents alter the baseline ventral and dorsal plaque to a significant degree and do not significantly affect the native arterial wall and the overall arterial diameter.

Introduction: About 20% of TIAs are due to large vessel disease. Carotid stenosis >50% which is causing a TIA or stroke needs to be definitely managed quickly in order to benefit. Alternatively, dual antiplatelet therapy may be considered. The objective of this study was to determine high-risk diagnostic findings associated with symptomatic carotid disease in ED patients with TIA to indicate patients requiring urgent carotid imaging. Methods: We performed a prospective Canadian multicenter cohort study, at 13 academic sites, of ED patients with TIA or non-disabling stroke from 2006-2014. Study research nurses recorded imaging findings on standardized data collection forms from the final reports of all imaging tests ordered in the ED on prospectively enrolled patients by treating emergency physicians. Symptomatic carotid disease was defined as carotid stenosis 50-99% or carotid dissection and was adjudicated by stroke neurology to be the etiology of the index event. Patients were followed by medical review and telephone up to 90 days. Univariate analysis was conducted for investigation results with our primary outcome. Results: The cohort included 305 patients with and 5,277 without symptomatic carotid disease. Positive predictors of symptomatic carotid disease included platelet count over 400 x 109/L (15.3% vs 7.6%; p=0.0095), blood glucose >15 mmol/L (11.4% vs 4.4%; p<0.0001), CT evidence of acute infarction (9.8% vs 4.1%; p<0.0001), CT evidence of old infarction (35.7% vs 24.1%; p<0.0001), and CT evidence of any infarct (43.3% vs 26.7%; p<0.0001). There were no negative predictors of symptomatic carotid disease. Conclusion: High-risk investigation findings suggestive of symptomatic carotid disease in ED TIA patients include platelet count over 400 x 109/L, blood glucose >15 mmol/L, CT evidence of any infarction. Patients with any of these findings should be considered for rapid carotid imaging.

Introduction: Emergency physicians can use B-mode Point-of-Care Ultrasound (POCUS) to identify a patient’s carotid vasculature including the common carotid artery (CCA), and carotid bulb (CB) as well as carotid bifurcation into the internal carotid artery (ICA) and external carotid artery (ECA). Radiology performed carotid ultrasound (RPCU) is performed using both B-mode and spectral Doppler ultrasound, a combination termed “duplex” ultrasound where first arteries are evaluated for stenosis using B-mode ultrasound, which is followed by flow measurements using Doppler. Performing flow measurements using Doppler may add a significant amount of time to the ultrasound, which makes it impractical for an emergency physician in a busy emergency department. Some institutional practices include arranging for outpatient RPCU to assess patients with Transient Ischemic Attack (TIA) and have them follow up in an outpatient TIA clinic. This study explored whether B-mode POCUS without Doppler may help identify Stroke or TIA patients in the emergency department with significant carotid stenosis (CS) by measuring the CCA, CB, and ICA lumen. Methods: Adult patients with an emergency physician diagnosis of stroke or TIA who were sent for RPCU were included in this study. An emergency medicine resident in their POCUS fellowship training performed a B-mode POCUS of the patient’s right and left CCA, CB and ICA with the patient sitting 90 degrees. Three measurements of each of the 3 sections were obtained and the mean calculated. This was then compared to the results from the RPCU as CS >50% or CS <50%. Results: 38 patients were included in the study between February and June 2013. We observed a correlation between absolute differences in comparing the right side of the carotid vasculature to the left side of the carotid vasculature with CS >50%. Also, in one case, the absolute lumen diameter with B-mode POCUS without Doppler predicted near complete CS which was confirmed on the RPCU. Conclusion: B-mode POCUS without Doppler may be useful in identifying patients with CS above and below 50% and may help identify patients who need expedited referrals for CS. However, further research is required before this method can be recommended.

Introduction: Impaired collateral circulation can lead to stroke during carotid endarterectomy. Carotid stump pressure (CSP) is used as a surrogate measure of collateral flow. The objective was to determine whether anatomical features obtained from digital subtraction angiography correlate with CSP during temporary internal carotid artery occlusion. The second objective was to use these features in combination to predict CSP. Methods: Digital subtraction angiographies from 102 patients obtained before endarterectomy were reviewed for anatomical variables including: degree of ipsilateral and contralateral carotid artery stenosis; patency of the anterior communicating artery; presence of cross-flow into ipsilateral middle cerebral artery branches; and size (< or ≥1 mm calibre) of the ipsilateral proximal anterior cerebral (A1), the contralateral A1, and the ipsilateral posterior communicating arteries. At surgery, systemic mean arterial pressure (MAP) and CSP were recorded. Multiple regression analysis was used to assess for anatomical features significantly associated with CSP. A “predicted CSP” equation was applied to 54 subsequent patients and correlated with measured CSP. Results: Variables correlating with CSP included MAP (p=0.001); the presence of severe contralateral carotid stenosis (p=0.002); patency of the anterior communicating artery (p=0.013); and the size of the contralateral A1 segment (p=0.029). Angiographic cross-flow, ipsilateral A1 size, and ipsilateral posterior communicating artery size were not significant. Predicted CSP correlated significantly with measured CSP (p<0.0001; R2=0.34). Conclusions: Anatomical features and systemic MAP are associated with carotid stump pressure during internal carotid artery occlusion and account for a significant amount of its variation.

Introduction: The Circle of Willis (CoW) is the most effective collateral circulation to the brain during internal carotid artery (ICA) occlusion. Carotid stump pressure (CSP) is an established surrogate measure of the cerebral collateral circulation. This study aims to use hemodynamic and computed tomography angiography measurements to determine the strongest influences upon the dependent variable, CSP. These findings could help clinicians noninvasively assess the adequacy of the collateral circulation and facilitate surgical risk assessment in an outpatient setting. Methods: CSP and mean arterial pressure were measured during carotid endarterectomy or during carotid balloon test occlusion in 92 patients. Intracranial arterial diameters were measured on computed tomography angiography at 16 different locations. Univariate and multivariate analyses were used to determine the key factors associated with CSP. In a subgroup of individuals (n=27) with severe (>70% North American Symptomatic Carotid Endarterectomy Trial) contralateral stenosis or occlusion, the same analysis was performed. Results: The contralateral anterior cerebral artery proximal to anterior communicating artery (A1) of the CoW had the strongest influence upon CSP, followed by the mean arterial pressure, the contralateral ICA diameter, and the anterior communicating artery diameter (R2=0.364). In the subgroup with high-grade contralateral ICA stenosis, the ipsilateral posterior communicating artery exerted the strongest influence (R2=0.620). Conclusions: During ICA occlusion, the anterior CoW dominates in preserving collateral flow, especially the contralateral A1 segment. In individuals with high-grade contralateral carotid stenosis, the posterior communicating artery calibre becomes a dominant influence. The most favourable anatomy consists of large contralateral A1 and anterior communicating arteries, and no contralateral carotid stenosis.

A healthy 58-year-old woman presented with recurrent swelling and pain of the nose and both auricules. Bruits were heard over both carotid arteries. Magnetic resonance angiography revealed stenosis of both internal carotid arteries. Relapsing polychondritis was diagnosed. These symptoms improved after treatment with prednisolone and azathioprine. Although relapsing polychondritis is sometimes associated with systemic vasculitis, large vessel arteritis is rare and can negatively affect prognosis. We conclude that the detection of systemic vascular lesions, including those involving the central nervous system, can play an important role in the diagnosis of relapsing polychondritis and that early treatment is essential for a good outcome.