Based on current literature, it appears premature for routine application of MRI as an imaging modality to assess carotid plaque characteristics associated with plaque vulnerability. Although MRI still holds promise, clinical application for plaque characterisation would require consensus regarding MRI settings and confirmation by histology. Predefined protocols for histology and MR imaging need to be established.

Background and Purpose-Because best medical treatment is improving, the risk of stroke in asymptomatic carotid artery stenosis (ACAS) may decline. We evaluated the risk of ischemic stroke and stratified it according to stroke subtype in patients with ACAS during long-term follow-up. Methods-In total, 4319 consecutive patients in the Second Manifestations of Arterial disease study with clinically manifest arterial disease or specific risk factors, but without a history of cerebrovascular disease, were included. Degree of stenosis was evaluated with duplex ultrasound scanning. Strokes during follow-up were classified according to subtype. Coxproportional hazard-regression models were used to evaluate the relationship between ACAS and future stroke. Results-We identified 293 (6.8%) patients with ACAS 50% to 99%, of whom 193 had 70% to 99% stenosis. In these subgroups, mean follow-up was 6.2 and 6.0 years, respectively. In total, 94 ischemic strokes occurred, of which 8 in ACAS 50% to 99% patients. The any territory annual ischemic stroke risk was 0.4% in 50% to 99% ACAS and 0.5% per year for 70% to 99% ACAS patients. The risk of ischemic stroke was not significantly increased in patients with ACAS 70% to 99% (hazard ratio, 1.5; 95% confidence interval, 0.7-3.5). Patients with ACAS 50% to 99% and ACAS 70% to 99% tended to have nonsignificantly more large vessel disease strokes (hazard ratio, 1.5; 95% confidence interval, 0.5-4.2 and hazard ratio, 1.7; 95% confidence interval, 0.5-5.6). Conclusions-Patients

Background and Purpose-Patients with both carotid stenosis and previously cervical radiation therapy are considered "high risk" for carotid endarterectomy (CEA). Carotid angioplasty and stenting (CAS) seems a reasonable alternative, but neither the operative risk for CEA nor the effectiveness of CAS has been proven. The purpose of this study was to evaluate perioperative and long-term outcome of both procedures in patients with radiation therapy. Methods-A systematic search strategy with the synonyms "carotid artery stenosis" and "cervical irradiation" was conducted in MEDLINE and EMBASE databases. To provide and compare estimates of outcomes, pooled and metaregression analyses were performed. Results-Twenty-seven articles comprising 533 patients undergoing radiation therapy (361 CAS and 172 CEA) fulfilled our inclusion criteria. Pooled analysis showed perioperative risk for "any cerebrovascular adverse event" (CVE) of 3.9% (95% CI, 2.3%-6.7%) in CAS studies against 3.5% (95% CI, 1.5%-8.0%) in CEA studies (Pϭ0.77). Risk for cranial nerve injury (CNI) after CEA was 9.2% (95% CI, 3.7%-21.1%) versus none after CAS. Late outcome showed rates of CVE favoring CEA (Pϭ0.014). The rate of restenosis Ͼ50% was significantly higher in patients treated with CAS compared with CEA (PϽ0.003). Conclusions-Both CAS and CEA proved to be feasible revascularization techniques with low risk for CVE. Although patients undergoing CEA had more temporary CNI, higher rates of late CVE and restenosis were identified after CAS.

Conclusion:Plaque morphology predicts ipsilateral stroke in asymptomatic carotid stenosis (ACS). The combination of embolic signal (ES) detection and plaque morphology provides greater prediction than either measure alone and can identify a high-risk group with an annual stroke rate of 8% and a low-risk group with a stroke rate of Ͻ1% per year.Summary: Intervention for high-grade ACS is increasingly questioned. There is evidence that, over the last decade, stroke risk with ACS has fallen with medical intervention alone (Abbott AL, Stroke 2009;40:e573-83; Marquardt I et al, Stroke 2010;41:e11-7). Nevertheless, although the percentage of patients with ACS who actually have a stroke is small, most ipsilateral strokes in patients with carotid stenosis are unheralded (Inzitari D et al, N Engl J Med 2000;342:1693-700). In this study, the authors examined the predictive value of a score based on plaque morphology and detection of ES with transcranial Doppler. Data were derived from the prospective, observational, international multicenter Asymptomatic Carotid Emboli Study (ACES). This study included 435 subjects with ACS Ͼ70% with baseline ultrasound images and transcranial Doppler data available. Prospective follow-up was for 2 years. Plaque morphology was graded using a classification system proposed by Geroulakos et al (Br J Surg 1993;80: 1274-7). In this system, type 1 plaques are uniformly echolucent, type 2 plaques are predominately echolucent (Ͼ50% of the plaque), type 3 plaques are predominately echogenic (Ͼ50% of the structure of the plaque), type 4 plaques are uniformly echogenic, and type 5 plaques cannot be classified because of heavy calcification or poor-quality images. Overall, type 1 and type 2 plaques are considered echolucent and type 3 and 4 plaques echogenic. In this study, 164 of the plaques (37.7%) were graded echolucent. At baseline, plaque echolucency was associated with an increased risk of ipsilateral stroke alone (hazard ratio, 6.43; 95% confidence interval, 1.36-30.44; P ϭ .019). Combining plaque echolucency and ES positivity at baseline was associated with a marked increased risk of ipsilateral stroke alone (hazard ratio, 10.61; 95% confidence interval, 2.98-37.82; P ϭ .003). Controlling for risk factors such as degree of carotid stenosis and antiplatelet medication did not alter this association.Comment: Data justifying prophylactic endarterectomy for asymptomatic carotid stenosis is now quite old. Results of surgery, angioplasty, and medical management of asymptomatic carotid stenosis are likely better now than a decade or two ago, but at a minimum, Ͼ20 carotid interventions for patients with asymptomatic carotid stenosis are needed to prevent one major stroke. There clearly needs to be a better approach to selecting patients with asymptomatic carotid stenosis for prophylactic endarterectomy. However, I doubt the approach presented here will be the answer. The classification system of carotid plaques described by Geroulakos et al has been available for many years and is simply not used, ...

Higher embolic potential in women and relatively stable female plaque morphology are the best-described factors influencing the difference in outcomes between men and women. However, the overall evidence for outcome differences by gender-specific characteristics in the literature is limited.

Asymptomatic carotid stenosis patients with prior cerebral infarction have a higher stroke risk during long-term follow-up than those without prior cerebral infarction. Evidence of prior ischemic events might help identify patients in whom carotid intervention is particularly beneficial.

Carotid stenotic lesions in patients with previous cervical radiation are less inflammatory and more fibrotic than carotid atherosclerotic lesions in non-radiated patients.

A small change in the process of care significantly reduced the delay from the index event to CEA, but in 2012 it still exceeded 14 days in the majority of patients. The definition of the "index event" has a large impact on the total duration of delay, and should therefore be uniform across studies.