Background-Thromboembolic disease secondary to complicated carotid atherosclerotic plaque is a major cause of cerebral ischemia. Clinical management relies on the detection of significant (Ͼ70%) carotid stenosis. A large proportion of patients suffer irreversible cerebral ischemia as a result of lesser degrees of stenosis. Diagnostic techniques that can identify nonstenotic high-risk plaque would therefore be beneficial. High-risk plaque is defined histologically if it contains hemorrhage/thrombus. Magnetic resonance direct thrombus imaging (MRDTI) is capable of detecting methemoglobin within intraplaque hemorrhage. We assessed this as a marker of complicated plaque and compared its accuracy with histological examination of surgical endarterectomy specimens. Methods and Results-Sixty-three patients underwent successful MRDTI and endarterectomy with histological examination. Of these, 44 were histologically defined as complicated (type VI plaque). MRDTI demonstrated 3 false-positive and 7 false-negative results, giving a sensitivity and specificity of 84%, negative predictive value of 70%, and positive predictive value of 93%. The interobserver (ϭ0.75) and intraobserver (ϭ0.9) agreement for reading MRDTI scans was good. Conclusions-MRDTI of the carotid vessels in patients with cerebral ischemia is an accurate means of identifying histologically confirmed complicated plaque. The high contrast generated by short T 1 species within the plaque allows for ease of interpretation, making this technique highly applicable in the research and clinical setting for the investigation of carotid atherosclerotic disease. Key Words: thrombus Ⅲ plaque Ⅲ carotid arteries Ⅲ imaging Ⅲ cerebral ischemia A therothrombotic carotid disease is a major cause of cerebral ischemia. Embolization from the surface of an atherosclerotic plaque to cerebral vessels can result in occlusion, which, if sufficiently prolonged, will result in cerebral infarction. More transient vascular occlusion may result in temporary ischemia, producing a neurological deficit that recovers with little or no residual brain damage. Clinically, transient ischemic attacks (TIAs) provide a warning of further cerebral ischemic events; Ϸ10% of patients who sustain a TIA, left untreated, will suffer a definitive stroke in the following year, 1 followed by a rate of 5% per annum. A warning TIA therefore offers the chance to intervene to prevent future permanent cerebral damage. The North American 2 and European 3 endarterectomy trials have both shown the positive benefit of surgery in patients with significant stenosis. The trials also indicate that lesser degrees of carotid disease are responsible for a significant number of strokes, but the risks of surgery matched or outweighed the benefits. Techniques have been sought to further define those among the group with moderate stenosis who are at high risk.In 1995, Stary et al, 4 for the American Heart Association, defined different atherosclerotic subtypes, the purpose being to pathologically identify plaque more likely to ...

MR IPH is a good predictor of ipsilateral stroke and TIA in patients with symptomatic mild to moderate (30%-69%) carotid stenosis. This technique could help in the selection of patients for carotid endarterectomy.

Background and Purpose-Carotid intraplaque hemorrhage (IPH), known to be associated with plaque instability, may convey a higher stroke risk. The aim of this study was to assess whether the identification of IPH by MRI predicts recurrent clinical cerebrovascular events. Methods-Sixty-six patients with high-grade symptomatic carotid stenosis underwent MRI of the carotid arteries and were followed until carotid endarterectomy or 30 days. Results-Of the 66 patients with a median follow up of 33.5 days, 44 (66.7%) were found on MRI to have ipsilateral carotid IPH. Fifteen recurrent events were associated with ipsilateral carotid IPH. Only 2 recurrent events occurred in the absence of IPH. IPH increased the risk of recurrent ischemia (hazard ratioϭ4.8; 95% CIϭ1.1 to 20.9, PϽ0.05). Conclusion-IPH as detected by MRI predicts recurrent cerebrovascular events in patients with symptomatic high-grade carotid stenosis.

Ruptured AAA remains a particularly hazardous condition to treat. There are a number of advantages of EVAR in this condition. A number of the problems early in the experience of EVAR have been addressed, but further experience is required to demonstrate its efficacy when compared with open repair.

Background Among asymptomatic patients with severe carotid artery stenosis but no recent stroke or transient cerebral ischaemia, either carotid artery stenting (CAS) or carotid endarterectomy (CEA) can restore patency and reduce long-term stroke risks. However, from recent national registry data, each option causes about 1% procedural risk of disabling stroke or death. Comparison of their long-term protective effects requires large-scale randomised evidence.Methods ACST-2 is an international multicentre randomised trial of CAS versus CEA among asymptomatic patients with severe stenosis thought to require intervention, interpreted with all other relevant trials. Patients were eligible if they had severe unilateral or bilateral carotid artery stenosis and both doctor and patient agreed that a carotid procedure should be undertaken, but they were substantially uncertain which one to choose. Patients were randomly allocated to CAS or CEA and followed up at 1 month and then annually, for a mean 5 years. Procedural events were those within 30 days of the intervention. Intention-to-treat analyses are provided. Analyses including procedural hazards use tabular methods. Analyses and meta-analyses of non-procedural strokes use Kaplan-Meier and log-rank methods. The trial is registered with the ISRCTN registry, ISRCTN21144362.

Background-It is recognized that complicated plaque largely accounts for the morbidity and mortality from atherosclerosis. Ideally, investigation of symptomatic and asymptomatic patients would identify atheromatous plaques independently of stenosis. We have previously shown that a magnetic resonance direct thrombus imaging (MRDTI) technique demonstrates complicated atheroma as high signal within the carotid arterial wall. We used this technique to examine the prevalence of complicated carotid plaque in vivo in the ipsilateral arteries of recently symptomatic patients with suspected carotid artery stenosis and to compare this with their contralateral arteries and with those of healthy age-and sex-matched controls. Methods and Results-The carotid arteries of 120 patients with suspected severe carotid artery stenosis and previous acute cerebral ischemia were imaged using MRDTI, as were 28 control arteries. High signal was not seen in any control artery. However, there was a 60% prevalence of high signal, suggestive of complicated plaque in the patients' ipsilateral arteries. The prevalence of high signal was significantly greater in the patients' ipsilateral vessels compared with the contralateral, asymptomatic side (60% versus 36%, 2 PϽ0.001), particularly for vessels of only moderate stenosis. Conclusions-MRDTI high signal suggestive of complicated plaque is prevalent in the ipsilateral carotid arteries of patients with carotid stenosis and recent cerebral ischemic events. MRDTI has a potential role in identifying "at risk" plaque, studying atherogenesis and the effects of plaque-modifying strategies. (Circulation. 2003;107:3053-3058.)

Despite the relative high operative mortality in the EVAR group, these preliminary results show that it is possible to recruit patients to a randomised trial of OAR and EVAR in patients with ruptured AAA. CT scanning does not delay treatment.

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