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The standard indication for intervention in asymptomatic disease is currently percent stenosis in the internal carotid artery as measured by the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method, which remains limited in discriminating power. Computed tomography angiography (CTA) is widely used to calculate NASCET stenosis, but also offers the opportunity to analyze carotid artery plaques from a morphological perspective that has not been widely used. We aim to improve stroke risk stratification of patients with carotid artery stenosis using plaque three-dimensional (3D) modeling and image analysis. Patients with computed tomography angiographies appropriate for 3D reconstruction were identified from a National Institutes of Health-designated stroke center database, and carotid arteries were segmented and analyzed using software algorithms to calculate contact surface area (CSA) between the plaque and blood flow, and volume of the flow lumen within the region of the plaque (lumen volume [LV]). These novel parameters factor in the 3D morphometry inherent to each carotid plaque and were compared between stroke and nonstroke groups. A total of 134 carotid arteries were analyzed, 33 of which were associated with an ipsilateral stroke. Plaques associated with stroke demonstrated statistically significant increases in average CSA (541.52 mm2) and LV (394.64 mm3) when compared with those not associated with stroke (371.18 mm2 and 245.92 mm3, respectively). When comparing area under the receiver operating characteristics curve between NASCET (0.65) percent stenosis, CSA (0.74), and LV (0.77), both CSA and LV demonstrated more favorable values in predicting stroke risk in patients with carotid stenosis. The data presented here demonstrate morphological features of carotid plaques that are independent of NASCET criteria stratification and may present an improved method in assessing stroke risk in patients with carotid artery stenosis. [ABSTRACT FROM AUTHOR]

The goal of this study was to compare the risk of stroke between patients with carotid artery disease with and without the presence of intraplaque hemorrhage (IPH) on magnetic resonance imaging. IPH in carotid stenosis increases the risk of cerebrovascular events. Uncertainty remains whether risk of stroke alone is increased and whether stroke is predicted independently of known risk factors. Data were pooled from 7 cohort studies including 560 patients with symptomatic carotid stenosis and 136 patients with asymptomatic carotid stenosis. Hazards of ipsilateral ischemic stroke (primary outcome) were compared between patients with and without IPH, adjusted for clinical risk factors. IPH was present in 51.6% of patients with symptomatic carotid stenosis and 29.4% of patients with asymptomatic carotid stenosis. During 1,121 observed person-years, 66 ipsilateral strokes occurred. Presence of IPH at baseline increased the risk of ipsilateral stroke both in symptomatic (hazard ratio [HR]: 10.2; 95% confidence interval [CI]: 4.6 to 22.5) and asymptomatic (HR: 7.9; 95% CI: 1.3 to 47.6) patients. Among patients with symptomatic carotid stenosis, annualized event rates of ipsilateral stroke in those with IPH versus those without IPH were 9.0% versus 0.7% (<50% stenosis), 18.1% versus 2.1% (50% to 69% stenosis), and 29.3% versus 1.5% (70% to 99% stenosis). Annualized event rates among patients with asymptomatic carotid stenosis were 5.4% in those with IPH versus 0.8% in those without IPH. Multivariate analysis identified IPH (HR: 11.0; 95% CI: 4.8 to 25.1) and severe degree of stenosis (HR: 3.3; 95% CI: 1.4 to 7.8) as independent predictors of ipsilateral stroke. IPH is common in patients with symptomatic and asymptomatic carotid stenosis and is a stronger predictor of stroke than any known clinical risk factors. Magnetic resonance imaging might help identify patients with carotid disease who would benefit from revascularization. [ABSTRACT FROM AUTHOR]

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Background and Objectives: The North American Symptomatic Carotid Endarterectomy Trial (NASCET) excluded patients with severe medical, angiographic and neurological risk factors. The aim of this study is to determine the safety and efficacy of protected stent angioplasty in these high-risk patients. Methods: Sixty-eight consecutive symptomatic NASCET-ineligible patients underwent protected stent-assisted carotid angioplasty. Patients were classified according to surgical risk based on Sundt criteria, and stratified for medical therapy according to stroke risk. Twenty-one patients were classified as Sundt grade 3 (30.8%) and 36 patients as grade 4 (52.9%). Results: The procedure was technically successful in all patients, with stenosis averaging 82.1% (range 70–99%) before the procedure and 6.3% (range 0–30%) after treatment. There were no periprocedural deaths or major strokes, but two patients had minor, non-embolic stokes (2.9%). During a mean clinical follow-up of 14.4 months (range 1–30 months), no new neurological events occurred in relation to the treated vascular territory. Conclusions: Carotid angioplasty with cerebral protection can be performed safely in high-risk patients. During the follow-up period, angioplasty was highly effective in terms of stroke prevention and arterial patency. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: This study determines the risk of ipsilateral ischaemic neurological events in relation to the degree of asymptomatic carotid stenosis and other risk factors. Methods: Patients (n=1115) with asymptomatic internal carotid artery (ICA) stenosis greater than 50% in relation to the bulb diameter were followed up for a period of 6–84 (mean 37.1) months. Stenosis was graded using duplex, and clinical and biochemical risk factors were recorded. Results: The relationship between ICA stenosis and event rate is linear when stenosis is expressed by the ECST method, but S-shaped if expressed by the NASCET method. In addition to the ECST grade of stenosis (RR 1.6; 95% CI 1.21–2.15), history of contralateral TIAs (RR 3.0; 95% CI 1.90–4.73) and creatinine in excess of 85μmol/L (RR 2.1; 95% CI 1.23–3.65) were independent risk predictors. The combination of these three risk factors can identify a high-risk group (7.3% annual event rate and 4.3% annual stroke rate) and a low risk group (2.3% annual event rate and 0.7% annual stroke rate). Conclusions: Linearity between ECST per cent stenosis and risk makes this method for grading stenosis more amenable to risk prediction without any transformation not only in clinical practice but also when multivariable analysis is to be used. Identification of additional risk factors provides a new approach to risk stratification and should help refine the indications for carotid endarterectomy. [Copyright &y& Elsevier]

The degree of carotid artery stenosis, calculated using catheter-based angiography and the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method, has been shown to predict the stroke risk in several, large, randomized controlled trials. In the present era, patients have been increasingly evaluated using computed tomography (CT) angiography (CTA) before carotid artery revascularization, especially as the use of transcarotid artery revascularization has increased. Interpretation of CTA findings regarding the degree of carotid stenosis has not been standardized, with both NASCET methods and the area stenosis used. We performed a single-institution, blinded, retrospective analysis of CTA studies using both the NASCET method and the CT-derived area stenosis to assess the concordance and discordance between the two methods when evaluating ≥70% and ≥80% stenosis. The UMass Memorial Medical Center vascular laboratory database was queried for all carotid duplex ultrasound scans performed from 2008 to 2017. The included patients were limited to those with duplex-defined ≥70% stenosis (defined as a peak systolic velocity of ≥125 cm/s and an internal carotid artery/common carotid artery ratio of ≥4), and a correlative CTA study performed within 1 year of the duplex ultrasound examination. A blinded review of all correlative CTA studies using centerline measurements on a three-dimensional workstation (Aquarius iNtuition Viewer; Terarecon, Durham, NC) was performed to characterize the degree of carotid stenosis using the NASCET method and the area stenosis method. Patients were excluded if revascularization had been performed between the two imaging studies. Of the 37,204 carotid duplex ultrasound scans reviewed (performed from 2008 to 2017), 3480 arteries met the criteria for duplex ultrasound-defined ≥70% stenosis. A correlative CTA study within 1 year of the duplex ultrasound examination was identified in 460 arteries, of which 320 were adequate quality for blinded review. The median interval between the duplex ultrasound and CTA examinations was 9.5 days. Concordance between the area stenosis and NASCET methods was poor for both ≥70% (κ = 0.32) and ≥80% (κ = 0.25) stenosis. Of the 247 arteries considered to have ≥70% area stenosis, 127 (51.4%) were considered to have ≥70% stenosis using the NASCET method. Of the 169 arteries considered to have ≥80% area stenosis, 44 (26.0%) were considered to have ≥80% stenosis using the NASCET method. The area stenosis CTA calculations of carotid artery stenosis dramatically overestimated the degree of carotid stenosis compared with that calculated using the NASCET method. Given that stroke risk estimates have been determined from trials that used the NASCET method, the area stenosis method likely overestimates the risk of stroke. Therefore, area stenosis calculations could lead to unnecessary carotid revascularization procedures. This model highlights the need for standardized usage of the NASCET method when using CTA as the imaging modality to determine the threshold for carotid revascularization. [ABSTRACT FROM AUTHOR]

Abstract: Atherosclerosis of the carotid artery accounts for more than 35% of all strokes. This contribution discusses the data from randomized clinical trials comparing stenting with surgery. [Copyright &y& Elsevier]