Comparison of the ECST, CC, and NASCET grading methods and ultrasound for assessing carotid stenosis

We compared three angiographic methods for grading of carotid stenosis and examined the correlation between angiographic and ultrasound findings. Two observers independently measured 111 carotid stenoses on arteriographic films of 84 patients. The stenoses were graded according to the European Carotid Surgery Trial (ECST), North American Symptomatic Carotid Endarterectomy Trial (NASCET), and Common Carotid (CC) methods. The results obtained by these methods were compared, and the interobserver reproducibility of the measurements was calculated. In addition, all angiographic results were compared to ultrasound findings obtained before angiography. Measurements using the CC method were the most reproducible and those using the NASCET method the least. The NASCET method underestimated the degree of stenosis compared to the other methods. The ECST and CC methods yielded almost identical results (97% agreement). Ultrasound provided an accuracy of 94% compared to ECST and CC methods and 84% compared to the NASCET method. Interobserver reproducibility of angiographic quantification of carotid stenoses was best for the CC and ECST methods and least for the NASCET method. Ultrasound demonstrated better accuracy than the ECST and CC methods. Received: 7 April 1999/Received in revised form: 5 October 1999/Accepted: 11 April 2000     

Carotid endarterectomy: Trials and tribulations

Since its introduction 40 years ago, the value of carotid endarterectomy has been controversial. In the early 1980s, several clinical trials were initiated to determine the efficacy of this operation in patients with carotid stenoses who were either symptomatic or asymptomatic for retinal or hemispheric ischemia. In 1991, interim results were published for the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the European Carotid Surgery Trial (ECST), both reporting efficacy for surgery in patients with symptomatic carotid artery stenosis of greater than 70%. Subgroup analyses revealed variable risk groups. The Veterans Administration (VA) Symptomatic Trial (Cooperative Studies Program 309 of the Department of Veterans Affairs) terminated early because of these results and its findings were consistent with the results of the larger trials. NASCET and ECST continue for symptomatic patients with carotid stenoses between 30% and 69%. The results of three trials in asymptomatic patients, the Mayo asymptomatic trial, the Carotid Artery Stenosis with Asymptomatic Narrowing: Operation Versus Aspirin trial, and the VA Asymptomatic Trial (Cooperative Studies Protocol 167 of the Department of Veterans Affairs), have been reported. None showed a statistically significant benefit for surgery in the prevention of stroke or death. However, none was sufficiently large to exclude such a benefit. The large Asymptomatic Carotid Atherosclerosis Study is in progress. Differences in the results and design of these trials are discussed as are restrictions in the applicability of their results.     

Accurate Measurement of Carotid Stenosis

The methods used for measurement of carotid artery stenosis are not uniform. Witness the chaos that developed when the North American Symptomatic Carotid Endarterectomy Trial (NASCET) group changed its classification system from area to linear measurements only to discover that the European Carotid Stenosis Trial (ECST) used still another angiographic definition of degree of stenosis so that the data from the two studies were not comparable. Fortunately, this has been reconciled by recalculation of the data. In still other studies, using unvalidated ultrasound instruments has made it difficult or impossible to compare results. In part, these problems have been the result of misdirected attempts to amalgamate concepts from Doppler and duplex ultrasound with those of arteriography. The former is more precise and accurate than the latter, yet its methodology is harder to apply and has not been generally distributed. Even such anatomical terms as “carotid bulb” are not standard. Ultrasonographers consider it to be the distal common carotid artery, to vascular surgeons it is the carotid sinus, while still others consider it to be both or neither. The present authors advocate a uniform methodology utilizing duplex ultrasound and predict that it plus magnetic resonance angiography will become the standard by which extracranial carotid artery disease is evaluated in the     

Prediction of angiographic carotid artery stenosis indexes by colour Doppler-assisted duplex imaging. A critical appraisal of the parameters used

The aim of our study was to establish colour Doppler-assisted duplex imaging (CDDI)-criteria to predict an angiographic internal carotid artery (ICA) stenosis of at least 70%, according to the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and European Carotid Surgery Trialists (ECST) methods of measurement. In the following, we describe the findings in 79 patients who were screened for carotid endarterectomy by CDDI and further evaluated by digital subtraction angiography (DSA). In 158 carotid arteries, 107 stenoses of > 30% and nine occlusions were found. Receiver operator characteristic graphs were constructed in order to calculate sensitivities and specificities of the assessment by CDDI in the prediction of high-grade stenoses determined by angiography. Optimal cut-off points were defined by highest accuracy which reflects the combination of high sensitivity and specificity. The critical index of a high-grade ICA stenosis according to the ECST method could be predicted with an accuracy greater than 90% by a systolic peak velocitiy of 1.25 m/s or an area reduction by CDDI of 70%. Corresponding values, 1.6 m/s and 80% area reduction, predicted the stenosis indexes according to the NASCET method less reliably, with accuracies of between 80% and 90%. Flow velocity criterion was slightly less accurate than the area reduction criterion by CDDI. Finally, double-blind evaluation performed by two readers per examination modality showed that the measurement of area reduction in CDDI is at least as reliable as stenosis indexes according to ECST and NASCET methods.     

Prospective study on the complication rate of carotid surgery

BACKGROUND: Randomized trials of carotid endarterectomy for high-grade stenosis have shown a benefit for surgery under the condition of low perioperative complication rates. Concerns have been expressed that the complication rates of carotid surgery are higher in everyday practice and may vary considerably between centers. We prospectively established the complication rate for carotid surgery in a single institution. DESIGN: Prospective 2-year study. All patients received pre- and postoperative neurological evaluation. Laboratory tests included pre- and postoperative brain imaging, intracranial and neck vessel sonography, conventional angiography, magnetic resonance angiography, and intraoperative monitoring. PARTICIPANTS: 108 consecutive patients: 54 symptomatic patients fulfilling the inclusion criteria of the European Carotid Surgery Trial (ECST) and 54 asymptomatic patients fulfilling the inclusion criteria of the North American Trial on Asymptomatic Stenoses (ACAS). SETTING: Single academic center with a high volume of carotid endarterectomies (>50 per year). Participating center in ECST. MAIN OUTCOME MEASURES: Stroke or death as defined in the randomized trials. RESULTS: The overall complication rate was 8.3% (95% CI 4.1-15.6%). Complications were more frequent in patients with symptomatic stenosis (11.1%, CI 4.6-23.3%) than in asymptomatic cases (5.6%, CI 1.5-16.4%). Three patients died (2 strokes, 1 myocardial infarction). Disabling strokes were found in 2 patients (Rankin scale scores 3 and 4). Nondisabling strokes (Rankin scale score 1 and 2) occurred in 4 patients. The complication rates for symptomatic and asymptomatic patients were higher than the ones reported in the randomized trials, but 95% confidence intervals showed that the differences were not statistically significant. The point estimates of complication rates still supported a benefit of surgery for patients with symptomatic stenosis, but denied a positive effect of endarterectomy for patients with asymptomatic stenosis. CONCLUSION: In this center, a beneficial effect of carotid surgery for asymptomatic stenoses cannot be safely assumed.     

颈动脉闭塞性疾病外科治疗发展史简

本文简单回顾了颈动脉闭塞性疾病的外科治疗历史。特别指出,自1991年北美症状性颈动脉内膜切除术试验和欧洲颈动脉外科手术试验等多中心大规模随机对照临床试验结果公布后,颈动脉内膜切除术在颈动脉粥样硬化性疾病治疗中的地位已毋庸置疑。该项外科手术技术虽然在中国起步较晚,但其发展前景良好。     

Three-dimensional computed tomography angiography and magnetic resonance angiography of carotid bifurcation stenosis.

PURPOSE: To evaluate the role of computed tomography angiography (CTA) and magnetic resonance angiography (MRA) in the quantification of atherosclerotic stenosis of carotid artery bifurcation in comparison with digital substraction angiography (DSA) and Doppler sonography (DS). MATERIALS AND METHODS: Twenty-five patients with atherosclerotic disease of the carotid arteries with proven stenosis by DSA, had spiral CTA, MRA using two- and three-dimensional time-of-flight gradient echo techniques, and DS using Doppler flow signal recording (total 47 carotid artery bifurcations). The degree of stenosis was measured according to the North American Symptomatic Carotid Endarterectomy Trial criteria: total occlusion (100%), severe (70-99%), moderate (30-69%) and mild (0-29%). The degree of stenosis measured by CTA, MRA and DS was compared to DSA, used as the gold standard. RESULTS: Ninety-seven percent of MRA measures were equivalent to DSA, and 3% were underestimated; 96% of CTA measures were equivalent to DSA, and 4% were underestimated; 77% of DS measures were equivalent to DSA, 21% were overestimated and 2% were underestimated. CONCLUSIONS: CTA and MRA are equally accurate methods in quantifying the degree of carotid bifurcation stenosis.     

Screening for carotid stenosis in patients with ischaemic heart disease.

In screening for carotid stenosis, an oblique cervical intra-arterial digital subtraction angiogram (IA-DSA) was obtained in 30 consecutive patients who underwent coronary angiography for work-up of myocardial infarction and/or follow-up of the status of previous percutaneous transluminal coronary angioplasty (PTCA) or revascularization (PTCR). In cases where carotid artery stenosis was suspected from IA-DSA, conventional angiography was obtained concurrently. Of 30 cases, three cases of severe carotid artery stenosis were detected. Carotid artery stenoses were in the right carotid bifurcation, and the extents of the stenoses were 70%, 75% and 90%. Ulceration was seen in the case with 75% stenosis. There were no complications associated with the coronary angiography, nor with the additional cervical IA-DSA which required less than 5 min to perform in all cases. Patients with ischaemic heart disease are a high risk group for carotid stenoses. This method of screening carotid stenosis is safe and requires only 20 ml of additional contrast media giving excellent resolution. The value of performing cervical IA-DSA in patients undergoing coronary angiography to screen for carotid stenosis is discussed.     

颈动脉支架成形术与药物治疗颈动脉狭窄的对比研究

目的 分析颈动脉支架成形术（CAS）与药物治疗颈动脉狭窄的疗效，并评价其安全性。方法 2003年11月至2006年3月采用颈动脉支架成形术治疗颈内动脉狭窄（狭窄率≥50％）21例,于围手术期进行抗血小板治疗及控制危险因素。单纯药物治疗组53例，药物治疗方案同治疗组。临床随访6～28个月。结果 21例手术操作完全成功，术后残余狭窄＜30％，术中3例患者出现一过性心率减慢、血压下降，2例出现颈内动脉远端血管痉挛，治疗后好转；术后未发生新的卒中，颈动脉超声未显示再狭窄。药物治疗组随访期间，5例患者再发卒中，颈动脉超声检查发现14例患者狭窄程度加重，其中2例血管造影证实颈内动脉完全闭塞。结论 与药物治疗组比较，CAS治疗颈内动脉狭窄可以提高患者的生活质量，而且比较安全，短期疗效较好，但有待大样本研究结果证实     

MR angiographic evaluation of carotid and intracranial arteries in Japanese patients scheduled for coronary artery bypass grafting

BACKGROUND AND PURPOSE: Stroke is a serious complication of coronary artery bypass grafting (CABG). Preoperative evaluation of the cerebral arteries to identify patients at increased risk of stroke after CABG is important. In a prospective study, we evaluated cerebral artery occlusive lesions with MR angiography in Japanese patients scheduled to undergo CABG to determine the prevalence of occlusive diseases in the extracranial carotid and intracranial arteries in this population and to identify preoperative risk factors for these patients. METHODS: The subjects were 151 consecutive patients (115 men and 36 women ranging in age from 41 to 82 years) who were scheduled for CABG under nonemergency conditions between October 1995 and February 1998. Carotid and intracranial arteries were examined for occlusive lesions with MR angiography. Patient demographics and risk factors including age, sex, hypertension, diabetes mellitus, hyperlipidemia, smoking habit, history of stroke, peripheral vascular disease and preoperative thromboembolic infarcts revealed by MR imaging were recorded and analyzed. RESULTS: Cervical carotid artery stenoses of more than 50% narrowing were detected in 16.6% of the subjects, and intracranial artery stenoses of more than 50% narrowing were detected in 21.2% of the subjects. Multiple logistic regression analyses identified peripheral vascular disease and lacunar infarcts in the basal ganglia as significant and independent predictors of cervical carotid arterial stenoses. No significant predictor for intracranial arterial stenoses was identified. CONCLUSIONS: The prevalence of extracranial carotid and intracranial artery stenosis in Japanese patients scheduled for CABG is considerably high. MR angiography is of value of identifying these patients. Preoperative evaluation of cranial arteries is recommended, particularly in patients with peripheral vascular disease and infarcts in the basal ganglia.     

Association between arterial bifurcation anatomy and angiographic plaque ulceration among 4,627 carotid stenoses

Stability of atheromatous plaques is influenced by local mechanical and haemodynamic factors, such as plaque motion and shear stress. However, although blood vessel anatomy is an important determinant of haemodynamics, particularly at bifurcations, there have been no previous clinical studies of the association between arterial anatomy and plaque ulceration. We therefore studied arterial anatomy and plaque ulceration using angiograms of 4,627 carotid bifurcations with atheromatous disease from the European Carotid Surgery Trial (ECST). We studied the vessel diameter and area ratios that have been shown in flow models to affect local haemodynamics and shear stress, and which are known to vary widely between and within individuals (internal to common, external to common, external to internal carotid artery and outflow/inflow area). Angiographic plaque surface morphology was defined as ulcerated or not ulcerated. To avoid any potential bias due to selective inclusion of patients in the ECST, we studied the contralateral, and usually asymptomatic, as well as the symptomatic carotid artery. To correct for the effects of systemic factors that might influence plaque stability, we also studied the relationship between the degree of asymmetry of bifurcation anatomy within individuals and the presence of plaque ulceration. Despite considerable inter-individual variation in carotid anatomy, we found no association between the prevalence of angiographic plaque ulceration and any of the anatomical parameters studied in either symptomatic or contralateral carotid arteries. There were also no associations between ipsilateral bifurcation anatomy and plaque ulceration in individuals with unilateral plaque ulceration. Carotid arterial anatomy does not appear to be an important determinant of plaque stability. Other factors that influence local haemodynamics, such as the anatomy and composition of the plaque itself may be more important.     

Interrelation between plaque surface morphology and degree of stenosis on carotid angiograms and the risk of ischemic stroke in patients with symptomatic carotid stenosis. On behalf of the European Carotid Surgery Trialists' Collaborative Group

BACKGROUND AND PURPOSE: The risk of ischemic stroke distal to an atherothrombotic carotid stenosis increases with the degree of stenosis. The main mechanism of stroke is thought to be embolism from fissured or ruptured plaque, but there are few published data on the relationship between plaque morphology and severity of stenosis and their independent effects on the risk of ischemic stroke. We sought to determine the interrelation between plaque surface morphology, degree of carotid stenosis, and the risk of ipsilateral ischemic stroke. METHODS: Severity of stenosis and plaque surface morphology were assessed on angiograms of the symptomatic carotid artery in 3007 patients in the European Carotid Surgery Trial and were related to baseline clinical characteristics, pathological characteristics of plaques examined at endarterectomy, and the risks of carotid territory ipsilateral ischemic stroke and other vascular events on follow-up. RESULTS: The early risk of ipsilateral ischemic stroke on medical treatment was closely related to the degree of carotid stenosis. However, the initial degree of carotid stenosis was not predictive of strokes occurring >2 years after randomization. Angiographic plaque surface irregularity and plaque surface thrombus at endarterectomy increased in frequency as the degree of stenosis increased (both P<0.0001). However, the degree of stenosis was still predictive of the 2-year risk of stroke on medical treatment after correction for plaque surface irregularity. Angiographic plaque surface irregularity was an independent predictor of ipsilateral ischemic stroke on medical treatment at all degrees of stenosis (hazard ratio=1.80; 95% CI, 1. 14 to 2.83; P=0.01). This relationship was maintained when the analysis was confined to strokes occurring >2 years after randomization (hazard ratio=2.75; 95% CI, 1.30 to 5.80; P=0.01). Neither the degree of stenosis nor plaque surface irregularity was predictive of the "background" stroke risk after endarterectomy or the risk of nonstroke vascular events. CONCLUSIONS: Angiographic plaque surface irregularity is associated with an increased risk of ipsilateral ischemic stroke on medical treatment at all degrees of stenosis. The increase in stroke risk with degree of stenosis is partly accounted for by the parallel increase in plaque surface irregularity and thrombus formation, but the degree of narrowing of the vessel lumen is still an independent predictor of ischemic stroke within 2 years of presentation.     

Risk factors and outcome of patients with carotid artery stenosis presenting with lacunar stroke. North American Symptomatic Carotid Endarterectomy Trial Group

OBJECTIVE: To examine the relationship between carotid artery stenosis, other risk factors, and lacunar stroke. BACKGROUND: Carotid artery stenosis in patients presenting with lacune stroke may be coincidental or causal. The distinction by risk factor profile is uncertain. The risk and cause of subsequent stroke, and benefit of carotid endarterectomy (CE) is unknown. METHODS: Stroke in patients entering the North American Symptomatic Carotid Endarterectomy Trial were classified as nonlacunar, possible lacune (symptoms without CT lacunae), or probable lacune (symptoms with CT lacunae). RESULTS: Of 1,158 patients with hemispheric stroke, 493 had features of lacunar stroke (283 possible and 210 probable). Lacunar stroke presented more commonly in patients with milder (<50%) degrees of internal carotid artery (ICA) stenosis (p = 0.003). History of diabetes and hyperlipidemia, not hypertension, were associated independently even after accounting for the degree of stenosis. Medically treated patients presenting with nonlacunar stroke had a low risk of subsequent lacunar events of 2.9% at 3 years in comparison with 9.2% for probable lacunar presentation (p = 0.03). For patients with 50 to 99% ICA stenosis, the relative risk reductions (RRRs) in stroke from CE were 35% when the presenting stroke was probable lacunar versus 61% when the stroke was nonlacunar. Patients presenting with a possible lacunar stroke had a 53% RRR. CONCLUSIONS: History of diabetes and hyperlipidemia were more important than arterial hypertension as risk factors for patients with lacunar stroke. Patients presenting with lacunar stroke more often had milder ICA stenosis. Although CE reduced the risk of stroke in all patients with 50 to 99% ICA stenosis, lesser benefits were observed in patients presenting with lacunar stroke.     

High rate of restenosis after carotid artery stenting in patients with high-grade internal carotid artery stenosis

OBJECTIVE: Carotid endarterectomy (CEA) is the gold-standard procedure for the majority of patients with high-grade symptomatic internal carotid artery stenosis and also for specified high-grade asymptomatic stenoses; however, a proportion of patients are treated with carotid endovascular therapy. We aimed to document medium-term clinical and neurosonographical outcome after carotid artery stenting (CAS). METHODS: 53 patients (mean age: 65 +/- 8 years) with high-grade (> or = 70 % by means of duplex sonography) carotid artery stenosis were enrolled into the study. Nineteen patients had asymptomatic, 34 patients had symptomatic stenoses. All patients had a pre-interventional CT, Doppler and duplex sonography, and digital subtraction angiography (DSA) or magnetic resonance angiography (MRA) prior to the procedural DSA. All patients were offered CEA as the gold-standard procedure and as an alternative to CAS. Both clinical and Duplex sonographical follow-up was obtained at day 1 and 7, month 1, month 3, month 6, month 12, and every subsequent 6 months after the procedure. Mean follow-up time was 22 +/- 1.6 months (+/- SEM). RESULTS: 2/53 patients suffered from stroke. A further 2 patients suffered from carotid artery occlusion shortly after CAS. The cumulative rate of restenosis during follow-up was 24.5 % (13/53). Four of these (7.5 %) were of high-grade and led to further interventional or surgical therapy. CONCLUSIONS: A high rate of restenosis was found during follow-up after CAS. Our analysis of non-selected patients emphasizes that CEA remains the gold-standard procedure for the treatment of symptomatic internal carotid artery stenosis. The frequently performed endovascular treatment of carotid stenosis outside the setting of a randomized controlled trial is not supported by our data.     

Reversed ophthalmic Doppler signal: a study of its significance

The pathophysiological significance in carotid artery stenoses of a collateral circulation via the external carotid and ophthalmic arteries is investigated with the use of three non-invasive techniques: Doppler ultrasonography, ophthalmodynamometry and ophthalmodynamography . 21 Carotid arteries with and 26 without a stenosis greater than 50% at angiography are studied. Finding a reversed flow direction in the ophthalmic artery points towards a low pressure in the carotid syphon and indicates that the patient is, hemodynamically speaking, in danger. This concerns the cerebral as well as the retinal circulation.     

Safety of latest-generation self-expanding stents in patients with NASCET-ineligible severe symptomatic extracranial internal carotid artery stenosis

BACKGROUND: Patients with symptomatic extracranial internal carotid artery stenosis (> or =70%) benefit from carotid endarterectomy when compared with medical management. However, independent risk factors can significantly increase the combined stroke and death risk after carotid endarterectomy. Carotid angioplasty and stenting (CAS) is a therapeutic option in patients who are otherwise at high risk or ineligible for carotid endarterectomy. Previous-generation self-expanding stents were hampered by length foreshortening, which limited their application in multifactorial occlusive extracranial internal carotid artery stenosis. METHODS: This is a single-center, prospective, open-label, safety study of CAS with the latest-generation self-expanding stents in patients with extracranial internal carotid artery symptomatic stenosis (> or =70%). All patients included were adjudicated to be ineligible for carotid endarterectomy by a vascular surgeon and/or a neurologist according to the exclusion criteria. Primary adverse events included death and all strokes (ipsilateral and contralateral). Secondary adverse events included transient ischemic attack, myocardial infarction, stent thrombosis, need for reintervention, and presence of hematomas. All adverse events were recorded at 24 hours, 30 days, and 6 months after CAS. RESULTS: Between June 1, 2001, and January 30, 2003, 23 consecutive patients (14 women and 9 men; mean age, 65 years; age range, 48-85 years) underwent 24 extracranial CAS procedures with the latest-generation self-expanding stents. All patients had one or multiple criteria for ineligibility according to the North American Symptomatic Carotid Endarterectomy Trial. Extracranial CAS was successful in all patients, with average residual stenosis of less than 20%. One patient (4%) experienced a stroke by the 30-day periprocedure examination. The total number of primary adverse events at 6 months after CAS was 2 strokes (9%), 1 of which was contralateral to the stent placement; there were no deaths. Twenty-two patients were asymptomatic at 6 months, with a modified Rankin scale score of 1 or less. Of the 2 patients who had a stroke, 1 had a follow-up modified Rankin scale score of 3. CONCLUSION: Extracranial CAS with the latest-generation self-expanding stents is a valid alternative treatment in high-risk or North American Symptomatic Carotid Endarterectomy Trial-ineligible patients.     

颈动脉内膜切除术防治缺血性脑血管病的近远期随访分析

目的 评价颈动脉内膜切除术防治缺血性脑血管病的近远期疗效。方法 14例有症状的重度颈动脉狭窄患者接受了颈动脉内膜切除术,对13例患者进行了3月～5年的随访。每位患者来院复查时行全面神经系统检查及TCD、颈动脉彩色多普勒超声检查,在随访过程中均行DSA检查1次。结果 13例随访病例在随访期间均无中风发生。除2例患者外,其余均无TIAs。TCD、颈动脉彩色多普勒超声检查和DSA检查发现2例再狭窄,其中1例无症状,另1例有TIAs,予内科保守治疗。结论 颈动脉内膜切除术是防治缺血性脑血管病的有效方法。多普勒超声检查是首选的有效的无创检查方法。TCD对病变的诊断有辅助作用。     

Endarterectomy, best medical treatment or both for stroke prevention in patients with asymptomatic carotid artery stenosis

Carotid endarterectomy (CEA) is currently frequently performed in subjects with asymptomatic carotid artery stenosis over 70%, as clinical trials like the Asymptomatic Carotid Atherosclerosis Study and Asymptomatic Carotid Surgery Trial demonstrated a significant benefit for stroke prevention. A low risk reduction in the long-term prevention of stroke or death and the required lower than 3% of surgical risk are associated with surgery. That means that an important number of patients needs to be operated to prevent 1 stroke over 5 years (number needed to treat: 21) with an absolute risk reduction of 5.4%. It is reasonable to consider CEA for patients aged 40-75 years and with asymptomatic stenosis of 60-99%, for patients with a life expectancy of at least 5 years, and in centres with a surgical morbidity-mortality of less than 3%. Therefore, it is of interest to identify high-risk patients with asymptomatic carotid stenosis who will more likely benefit from surgery. Techniques such as ultrasound or magnetic resonance imaging may identify plaque morphology or detect clinically asymptomatic embolization. CEA combined with the best medical treatment and good management of modifiable risk factors might be superior to medical management alone or surgery in preventing stroke. There is no level I evidence to support carotid artery stenting in asymptomatic carotid stenosis even in a subgroup of patients with a high surgical risk.     

Asymptomatic cervical artery stenoses in Moscow

The risk of stroke related to asymptomatic carotid artery stenosis is known to be increased in high-grade or rapidly progressive stenosis. Information of the prevalence in the general population is required for the recommendation of screening methods to detect patients needing prophylactic treatment. We studied the prevalence and the grade of severity of extracranial carotid and vertebral artery obstructions by means of Doppler sonography in 529 asymptomatic Russians (m: 343, f: 186; 36-84 years, mean: 58.4 years) living in Moscow city. Internal carotid artery obstructions of more than 50% stenosis were present in 22 (=4.2%) subjects, 8 of them (1.5%) had bilateral lesions. Appropriate abnormal findings in vertebral arteries were found in 11 (=2.1%) subjects, in 1 of them bilaterally. Affection of both the carotid and the vertebral arteries was noted in 4 (=0.8%) individuals. There were no sexual differences. The risk factor which correlated most significantly with cervical arterial lesions was hypertension. Carotid lesions were also significantly associated with age and smoking, but not with diabetes or hyperlipoproteinemia. The prevalence of cervical artery stenoses was found to be lower than in western reports, which may be due to different technical equipment and different study design.     

Observer variation in the interpretation of intra-arterial angiograms and the risk of inappropriate decisions about carotid endarterectomy.

OBJECTIVE--To determine how often observer variation in the interpretation of intra-arterial angiograms might alter the decision whether or not to refer patients for carotid surgery. METHODS--A prospective study was carried out in a consecutive series of 99 patients with transient ischaemic attacks and minor strokes. Interpretable angiographic films were available for 179 carotid artery bifurcations. Stenosis of the internal carotid artery was measured using mm scales, independently by three different radiologists (A, B, and C), using the European Carotid Surgery Trial method. RESULTS--An analysis of the grouped data showed good to moderate agreement by kappa statistics for radiologists A v B, B v C, and A v C of 0.68, 0.60, and 0.70 respectively. The mean absolute difference in the estimate of stenosis by each of the different radiologists (interobserver variation) was 9.5% and for each radiologist on two separate occasions (intraobserver variation) 8.4%. The degree of observer error was smallest among severely stenosed arteries. Although the absolute differences were small, "clinically important" differences which could change the treatment recommended from surgery to no surgery (or vice versa) occurred between radiologists A and B, B and C, and A and C in: seven (3.9%), six (3.4%), and 11 (6.1%) vessels respectively. CONCLUSIONS--Because observer variation affects all of the imaging methods (Doppler, duplex, contrast arteriography, and MR angiography) used to select patients with transient ischaemic attack and stroke, these findings are likely to be widely relevant. Any centre assessing patients with cerebrovascular disease will need to implement strict quality control measures in the interpretation of angiograms (and other vascular imaging procedures) to minimise observer error and thereby reduce the number of inappropriate decisions made to refer for carotid artery surgery or not.