Improved prognosis for asymptomatic carotid stenosis with prophylactic carotid endarterectomy.

BACKGROUND AND PURPOSE: The value of carotid endarterectomy in asymptomatic patients with high-grade stenosis is controversial. The objective of this study is to compare the immediate and long-term outcome of patients after carotid endarterectomy for asymptomatic carotid stenosis (greater than 75%) with the reported natural history of patients followed nonoperatively to determine whether carotid endarterectomy reduces the subsequent neurological event rate. METHODS: The data from 141 carotid endarterectomies performed in 123 patients between January 1980 and December 1986 were reviewed from the perspective of perioperative results and long-term follow-up to January 1990, providing a follow-up ranging from 3 to 10 years. The mean follow-up was 56.6 months (range 27-117 months). RESULTS: There were no perioperative deaths. There were two postoperative stokes: one in the cerebellar distribution and one in the middle cerebral distribution. During the course of follow-up, no patient suffered a stroke in the hemisphere ipsilateral to carotid endarterectomy. One patient developed ipsilateral transient ischemic attacks 24 months after surgery associated with carotid restenosis. A total of three patients developed four recurrent carotid stenoses, for an incidence of 2.8%. All four recurrences were corrected surgically. CONCLUSIONS: These findings are in marked contrast to the reported natural history of patients with greater than 75% stenosis in which the 1-year neurological event rate is 18% and the 1-year stroke rate is 5%. Although final proof of efficacy for prophylactic carotid endarterectomy in asymptomatic patients will await the outcome of randomized trials, until these data are available, prophylactic carotid endarterectomy is justified in centers of excellence that can perform the surgery with low perioperative risk.     

Cranial nerve paralysis following carotid endarterectomy

During the past seven years 347 patients have been entered into a data bank at the Duke University Medical Center for evaluation of transient neurologic ischemia. One hundred fifty eight of these patients had carotid endarterectomies of whom 24 (15.1%) developed 26 (16.4%) peripheral cranial nerve palsies. Injury to the peripheral portion of the hypoglossal nerve was noted in 13 patients, to the cervical branch of the facial nerve in five and to the recurrent laryngeal nerve branch of the vagus in eight. Complete recovery of nerve function usually occurred within four months but residual deficit was present at one year in two patients with facial nerve and four with hypoglossal nerve involvement. Even though these complications of carotid endarterectomy are generally benign and transient, the frequency of occurrence can be reduced if careful attention is given to anatomic localization of the cranial nerves during surgery.     

Cerebral hyperperfusion syndrome

Cerebral hyperperfusion syndrome (CHS) after carotid endarterectomy is characterised by ipsilateral headache, hypertension, seizures, and focal neurological deficits. If not treated properly it can result in severe brain oedema, intracerebral or subarachnoid haemorrhage, and death. Knowledge of CHS among physicians is limited. Most studies report incidences of CHS of 0-3% after carotid endarterectomy. CHS is most common in patients with increases of more than 100% in perfusion compared with baseline after carotid endarterectomy and is rare in patients with increases in perfusion less than 100% compared with baseline. The most important risk factors in CHS are diminished cerebrovascular reserve, postoperative hypertension, and hyperperfusion lasting more than several hours after carotid endarterectomy. Impaired autoregulation as a result of endothelial dysfunction mediated by generation of free oxygen radicals is implicated in the pathogenesis of CHS. Treatment strategies are directed towards regulation of blood pressure and limitation of rises in cerebral perfusion. Complete recovery happens in mild cases, but disability and death can occur in more severe cases. More information about CHS and early institution of adequate treatment are of paramount importance in order to prevent these potentially severe complications.     

Risk of stroke during coronary artery bypass graft surgery in patients with internal carotid artery disease documented by angiography

We retrospectively identified 144 patients who underwent coronary artery bypass graft (CABG) surgery in the presence of angiographically documented greater than or equal to 50% internal carotid stenosis or occlusion. Of these, 115 patients had bilateral carotid lesions and received combined operations involving carotid endarterectomy on only one side. The remaining 29 patients, including 11 with bilateral carotid lesions, underwent coronary bypass alone. Nine cerebral infarcts occurred (6%), but only three strokes (2%) were appropriate to the cerebral hemisphere ipsilateral to unoperated carotid stenosis. There was one stroke (3%) among the 29 patients who did not undergo combined procedures. In the group of 115 patients with bilateral carotid disease who received unilateral combined carotid endarterectomy there were 8 perioperative strokes (7%), of which 6 were ipsilateral to the endarterectomy. Asymptomatic unilateral less than 90% ICA stenosis or ICA occlusion does not increase stroke risk during CABG surgery.     

Should carotid stenting replace carotid endarterectomy in routine clinical practice?

Carotid stenting has the advantage over endarterectomy of avoiding the complications of neck incision, and often of general anaesthesia too, but it has not yet been shown convincingly to be either as safe or as effective. Only randomised controlled trials allow proper comparison of these aspects of stenting and endarterectomy, but the results to date have been contradictory. Some trials have shown similar 30-day risks of stroke or death, while others have been stopped early because of significantly worse outcome in the stenting group. Inclusion of investigators with limited experience of carotid stenting devices may have contributed to poor results in some trials. The published trials are rather heterogeneous, none is large enough to provide convincing data, and there is very limited long-term follow-up information. We therefore need more data from the ongoing randomised trials before recommending that stenting should in general replace endarterectomy for either symptomatic or asymptomatic carotid stenosis.     

Prognosis of asymptomatic carotid occlusion

Ninety-four asymptomatic patients with internal carotid artery occlusion were followed for a mean of 44 months, 16% suffered strokes and 11.7% reported transient ischemic attacks (TIA). The annual stroke and TIA rates were 4.4% and 3.2%, respectively, the annual mortality was 11.3%. In 27 asymptomatic patients progression of extracranial arterial disease to occlusion was observed: 7.4% of these patients suffered from stroke and 18.5% reported TIA's during that period. Thus the annual stroke rate was lower (1.9%) but the TIA rate higher (4.7%) than post-occlusive rates. These data reflect an increase risk in patients with progressive high-degree carotid stenosis which continues after occlusion. This may favour carotid endarterectomy for selected patients in the pre-occlusive state because medical treatment has not been shown to prevent progression of stenosis to occlusion.     

Measurement of cerebral reserve capacity using acetazolamide loading xenon CT CBF before carotid endarterectomy

BACKGROUND AND PURPOSE: Brain swelling and/or hemorrhage can occur after carotid endarterectomy. This phenomenon is called the hyperperfusion syndrome. Several factors contribute to this syndrome. One is reperfusion in a maximally dilated vessel which means disappearance of cerebral reserve capacity (CRC). The aim of the study was to determine whether CRC measurement was useful for intraoperative and postoperative management of carotid endarterectomy. PATIENTS AND METHODS: We studied 64 cases (male 53, female 11), 49-79 years. CRC was measured preoperatively using acetazolamide loading Xenon CT CBF examination (XeCT). Hypothermia (34-35 C) was induced during surgery in a patient with no CRC. Anesthesia was maintained the night after surgery and the systolic blood pressure was controlled below 120 mmHg. RESULTS: CRC was absent in 10 patients. Postoperative CT did not reveal any hemorrhage or brain swelling. One patient experienced a transient restless state. DISCUSSION: and conclusions: Cerebral hyperperfusion syndrome has been reported in 0.3 approximately 6.0% of patients following carotid endarterectomy (vs 1.6% in our study without hemorrhage or brain swelling). These data suggest that information on CRC could be useful for selection and perioperative management of patients during carotid endarterectomy.     

标准式与翻转式颈动脉内膜切除术的对比分析

目的 探讨标准式颈动脉内膜切除术（standard carotid endarterectomy,sCEA）和翻转式颈动脉内膜切除术（eversion carotid endarterectomy,eCEA）治疗颈动脉狭窄的临床应用。 方法 回顾性分析2008年4月～2011年10月我科住院的颈动脉狭窄患者265例（其中11例患者分期行双侧手术,每例按2例单独病例进行计算,共计276例）。根据狭窄的部位和程度采取标准式与翻转式两种不同手术方式,sCEA组80例,eCEA组196例。回顾性分析两种术式患者术中阻断时间、术中神经损伤发生率、术后症状缓解率、术中转流管的应用及术后血管再狭窄率。 结果 两组患者术中阻断时间［sCEA组（25.3±11.2）min vs eCEA组（23.1±9.8）min,P＝0.106］、神经损伤发生率［sCEA组（3.75%） vs eCEA组（6.12%）,P＝0.62］、术后症状缓解率［sCEA组（95.00%）vs eCEA组（96.93%）,P＝0.669］差异均无显著性。术中应用转流管12例。术后再狭窄率sCEA组2例（2.50%）,eCEA组无再狭窄患者,差异具有显著性（P＝0.026）。随访3～35个月,两组患者均未再有新发脑梗死。 结论 标准式及翻转式颈动脉内膜切除术均可有效地治疗颈动脉狭窄。     

Carotid endarterectomy: a review

BACKGROUND: Since the validation of carotid endarterectomy (CEA) as an effective means of stroke prevention, there has been renewed interest in its best indications and methods, as well as in how it compares to carotid angioplasty and stenting (CAS). This review examines these topics, as well as the investigation of carotid stenosis and the role of auditing and reporting CEA results. INVESTIGATION: Brain imaging with CT or MRI should be obtained in patients considered for CEA, in order to document infarction and rule out mass lesions. Carotid investigation begins with ultrasound and, if results agree with subsequent, good-quality MRA or CT angiography, treatment can be planned and catheter angiography avoided. An equally acceptable approach is to proceed directly from ultrasound to catheter angiography, which is still the gold-standard in carotid artery assessment. INDICATIONS: Appropriate patients for CEA are those symptomatic with transient ischemic attacks or nondisabling stroke due to 70-99% carotid stenosis; the maximum allowable stroke and death rate being 6%. Uncertain candidates for CEA are those with 50-69% symptomatic stenosis, and those with asymptomatic stenosis > or = 60% but, if selected carefully on the basis of additional risk factors (related to both the carotid plaque and certain patient characteristics), some will benefit from surgery. Asymptomatic patients will only benefit if surgery can be provided with exceptionally low major complication rates (3% or less). Inappropriate patients are those with less than 50% symptomatic or 60% asymptomatic stenosis, and those with unstable medical or neurological conditions. TECHNIQUES: Carotid endarterectomy can be performed with either regional or general anaesthesia and, for the latter, there are a number of monitoring techniques available to assess cerebral perfusion during carotid cross-clamping. While monitoring cannot be considered mandatory and no single monitoring technique has emerged as being clearly superior, EEG is most commonly used. "Eversion" endarterectomy is a variation in surgical technique, and there is some evidence that more widely practiced patch closure may reduce the acute risk of operative stroke and the longer-term risk of recurrent stenosis. CAROTID ANGIOPLASTY AND STENTING: Experience with this endovascular and less invasive procedure grows, and its technology continues to evolve. Some experienced therapists have reported excellent results in case series and a number of randomized trials are now underway comparing CAS to CEA. However, at this time it is premature to incorporate CAS into routine practice replacing CEA. AUDITING: It has been shown that auditing of CEA indications and results with regular feed-back to the operating surgeons can significantly improve the performance of this operation. Carotid endarterectomy auditing is recommended on both local and regional levels.     

Progression of carotid disease after endarterectomy: A Doppler ultrasound study

The clinical prognosis and evolution of carotid lesions after unilateral endarterectomy were determined in 64 patients examined 1 to 13 years after surgery (mean observation period, 6 years). Surgery mainly was confined to symptomatic patients with a stenosis only on the appropriate side. Average annual stroke rate was 1.6% on the operated and 0.8% on the nonoperated side. Direct Doppler examination at follow-up revealed a recurrent stenosis (≥50%) or occlusion in 36% of the operated carotid arteries, not significantly different from the proportion of progressive carotid lesions on the nonoperated side (27%). In total, 43.8% of the patients had developed new lesions in one or both carotid arteries, as compared to previous angiographic findings. About 30% of the progressive lesions were associated with symptoms of transient ischemic attacks or stroke, as opposed to 5.5% of vessels without progression of lesions (p < 0.001). The incidence of recurrent stenosis on the operated side is considerably higher than that previously reported for symptomatic recurrent stenosis, but may represent the natural course of carotid disease in this population, in which carotid surgery thus should not be regarded as definitive treatment.     

Immediate and long-term results of carotid endarterectomy

We review the long-term results of carotid endarterectomy in 200 consecutive patients operated on from 1980 to 1987. The patients were part of an ongoing study using duplex scanning to assess the status of the carotid bifurcation before and after endarterectomy. The average follow-up for the patients was 31 months. The indications for surgery were transient ischemic attacks in 87 (43.5%) and stroke in 36 (18%) patients; 77 patients (38.5%) were asymptomatic. In 176 sides (88%), the degree of stenosis exceeded 50% in terms of diameter reduction. The perioperative stroke rate was 2.3% in patients with transient ischemic attacks, 2.8% in patients with strokes, and 1.3% in asymptomatic patients. There was one perioperative death (0.5%). There were five occlusions of the internal carotid artery, one during the perioperative period and four after discharge; in three patients the occlusion was associated with the development of a stroke. There was a restenosis rate of 19.7% secondary to myointimal hyperplasia; such lesions did not appear to contribute to new ischemic events during or after their development. The mean stroke incidence after the decision was made for carotid endarterectomy was 2.8%/yr in the patients with transient ischemic attacks, 6.2%/yr in the patients with stroke, and 0.65%/yr in the asymptomatic patients. The annual death rate was 6% for the entire group, 5.5%/yr in the patients with transient ischemic attacks, 9.2%/yr in the patients with stroke, and 4.6%/yr in the asymptomatic patients.     

MRI lesions after invasive therapy of carotid artery stenosis: a risk-modeling analysis

BACKGROUND: Diffusion-weighted imaging (DWI) abnormalities can frequently be detected after carotid endarterectomy (CEA) and carotid angioplasty with stent placement (CAS) of the carotid arteries. We looked for possible predictors for the development of DWI lesions during the intervention. METHODS: We investigated 41 patients who underwent CAS without protection devices and 93 patients who underwent CEA. DWI studies were performed 1 day before and after the intervention. RESULTS: Ischemic complications consisted of two strokes (2.2%) in the CEA group and one stroke (2.4%) in the CAS group. DWI lesions were detected in 28.0% of all patients after intervention. Using a multivariate regression analysis, diabetes mellitus (DM), hyperlipidemia, symptomatic stenosis, age and CAS were found to be significant predictors for the occurrence of DWI lesions. CONCLUSIONS: DWI is an objective and highly sensitive method for monitoring interventions of the carotid arteries. Our results point to an increased risk of patients with diabetes and hyperlipidemia to develop DWI lesions during invasive therapy of the ICA.     

New brain lesions after carotid stenting versus carotid endarterectomy: a systematic review of the literature

BACKGROUND AND PURPOSE: Against the background of a relatively low rate of clinical events during carotid angioplasty and stenting (CAS) or carotid endarterectomy (CEA), diffusion-weighted imaging (DWI) is increasingly being used to compare the incidence of new ischemic lesions after both procedures. In addition, DWI may also provide a means of defining the role of different CAS techniques on this adverse outcome. Therefore, we performed a PubMed search and systematically analyzed all peer-reviewed studies published between January 1990 and June 2007 reporting on the occurrence of new DWI lesions after CAS or CEA. Summary of Review- In 32 studies comprising 1363 CAS and 754 CEA procedures, the incidence of any new DWI lesion was significantly higher after CAS (37%) than after CEA (10%) (P<0.01). Similar results were obtained in a meta-analysis focusing on those studies directly comparing the incidence of new DWI lesions after either CEA or CAS (OR, 6.1; 95% CI, 4.19 to 8.87; P<0.01). The use of cerebral protection devices (33% vs 45% without; P<0.01) and closed-cell designed stents during CAS (31% vs 51% with open-cell stents; P<0.01), as well as selective versus routine shunt usage during CEA (6% vs 16%; P<0.01) significantly reduced the incidence of new ipsilateral DWI lesions. CONCLUSIONS: New DWI lesions occur more frequently after CAS than after CEA. However, technical advances mainly in the field of endovascular therapy potentially reduce the incidence of these adverse ischemic events. In this scenario, DWI appears to be an ideal tool to compare and further improve both techniques.     

Infrequency of blacks among patients having carotid endarterectomy

We reviewed demographic data on patients having 2,256 carotid endarterectomies in eight large hospitals in North Carolina to determine the frequency of blacks among these patients. Blacks comprised only 4.6% of the patients having carotid endarterectomy even though they comprised 26% of all patients discharged and 22% of the general population of the state. Data from the National Inpatient Profile of the Commission on Professional and Hospital Activities, which represents patients discharged from short-term, nonfederal hospitals throughout the United States, show that nationwide, blacks comprise only 2.7% of the patients having carotid endarterectomy, whereas they comprise 12.0% of all patients discharged, 12.1% of the general population, and 10.7% of patients discharged following Class I surgical procedures. Blacks have only 67 carotid endarterectomies per 100,000 patients discharged; this rate is five or more times higher in whites. Among black patients having carotid endarterectomy, women predominate, whereas men predominate among white patients having carotid endarterectomy (p = 0.006). The underrepresentation of blacks among patients having carotid endarterectomy lends support to the concept that carotid vascular disease in blacks is distributed intracranially rather than extracranially as opposed to the extracranial rather than intracranial distribution in whites.     

Systematic comparison of the early outcome of angioplasty and endarterectomy for symptomatic carotid artery disease

BACKGROUND AND PURPOSE: Endoluminal treatment is being increasingly used for carotid artery disease. The aim of this study was to compare the stroke and death risk within 30 days of endovascular treatment or endarterectomy for symptomatic carotid artery disease. METHODS: systematic comparison of the 30-day outcome of angioplasty with or without stenting and endarterectomy for symptomatic carotid artery disease reported in single-center studies, published since 1990, was performed. RESULTS: Thirty-three studies (13 angioplasty and 20 carotid endarterectomy) were included in this analysis. Carotid stents were deployed in 44% of angioplasty patients. Mortality within 30 days of angioplasty was 0.8% compared with 1.2% after endarterectomy (OR 0.68, 95% CI 0.43 to 1.05; P=0.6). The stroke rate was 7.1% for angioplasty and 3.3% for endarterectomy (OR 2.22, CI 1.62 to 3.04; P<0.001), while the risk of fatal or disabling stroke was 3.2% and 1.6%, respectively (OR 2.09, CI 1.3 to 3.33; P<0.01). The risk of stroke or death was 7.8% for angioplasty and 4% for endarterectomy (OR 2.02, CI 1.49 to 2.75; P<0.001), while disabling stroke or death was 3.9% after angioplasty and 2.2% after endarterectomy (OR 1.86, CI 1.22 to 2.84; P<0.01). CONCLUSIONS: In the treatment of symptomatic carotid artery disease, the risk of stroke is significantly greater with angioplasty than carotid endarterectomy. At present, carotid angioplasty is not recommended for the majority of patients with symptomatic carotid artery disease.     

Angioplasty and stenting for stroke prevention: good questions that need answers

Extracranial and intracranial angioplasty and stenting of the cerebral vessels are being performed more frequently. One clinical trial demonstrated equivalent outcomes between extracranial carotid angioplasty and carotid endarterectomy, but the results in both groups were suboptimal. Concerns remain about the iatrogenic stroke rate after angioplasty, especially for asymptomatic patients. Angioplasty, with or without stent placement, also offers a potential new therapeutic approach for patients with intracranial stenosis and vertebrobasilar lesions, although these procedures have been performed in uncontrolled fashion.     

Carotid artery stenting:the need for randomised trials

Endovascular treatment for carotid artery stenosis avoids some of the complications of carotid endarterectomy, but has not been widely accepted. Concerns about the risks and benefits of endovascular treatment led to the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS). There was no difference in major outcome events between endovascular treatment and carotid endarterectomy, but the rate of procedural stroke or death was higher than desirable. There was no difference either in the rate of stroke during follow-up, but the confidence intervals were very wide and severe ipsilateral carotid stenosis was more frequent 1 year after endovascular treatment than after carotid surgery. Two other randomised trials of carotid stenting were stopped early after poor outcomes in stented patients. These early trials used techniques which have now been superseded, but the results emphasise the need to improve the safety of endovascular treatment. Recent advances designed to improve safety include new designs of stents and delivery systems, and devices designed to protect the brain from embolisation during stenting. However, there is little convincing evidence that these new devices reduce the rate of stroke. Moreover, a systematic review of the existing randomised trial data concluded that there the current evidence does not support a shift away from recommending carotid endarterectomy as the standard treatment for carotid stenosis. There is therefore a clear need for further randomised trials of carotid stenting. Three of the ongoing trials, EVA-3S, SPACE and ICSS (CAVATAS-2), have prospectively agreed to combine individual patient data after completion of follow-up. This meta-analysis will provide results similar to a mega-trial and should also allow informative subgroup analyses. The co-operation between the trials in agreeing to perform this meta-analysis is a major advance in trial design. The result should determine whether carotid stenting truly rivals carotid endarterectomy as the treatment of choice for carotid stenosis.     

Cerebral blood volume, endarterectomy and SPECT

Cerebral blood flow and cerebral blood volume were measured and quantified using single photon emission computed tomography before and after unilateral endarterectomy in 3 patients with bilateral severe lesions of the internal carotid artery. These parameters were measured using an intravenous injection of 133 Xenon and 99m Technetium respectively. Before endarterectomy cerebral blood volume was high in all patients suggesting a focal vasodilatation in response to a reduced cerebral perfusion pressure. After endarterectomy a decrease of cerebral blood volume and an increase of cerebral blood flow were observed. These preliminary results confirm that the hemodynamic adaptative mechanisms secondary to carotid occlusion are reversible when the stenosis is removed and demonstrate that these changes can be accurately measured using single photon emission computed tomography. Positron emission tomography was previously considered to be the only method able to quantify cerebral blood volume in man. Single photon emission computed tomography can also be considered a reliable technique to measure both cerebral blood flow and cerebral blood volume. This technique can then be used to assess individual cerebral vascular adaptative states and to evaluate the influence of cerebral hemodynamic changes on stroke occurrence in large longitudinal studies.     

Variations in middle cerebral artery blood flow investigated with noninvasive transcranial blood velocity measurements

Observations on blood velocity in the middle cerebral artery using transcranial Doppler ultrasound and on the ipsilateral internal carotid artery flow volume were obtained during periods of transient, rapid blood flow variations in 7 patients. Five patients were investigated after carotid endarterectomy. A further 2 patients having staged carotid endarterectomy and open heart surgery were investigated during nonpulsatile cardiopulmonary bypass. The patient selection permitted the assumption that middle cerebral artery flow remained proportional to internal carotid artery flow. The integrated time-mean values from consecutive 5-second periods were computed. The arithmetic mean internal carotid artery flow varied from 167 to 399 ml/min in individual patients, with individual ranges between +/- 15% and +/- 35% of the mean flow. The mean middle cerebral artery blood velocity varied from 32 to 78 cm/sec. The relation between flow volume and blood velocity was nearly linear under these conditions. Normalization of the data as percent of the individual arithmetic means permitted a composite analysis of data from all patients. Linear regression of normalized blood velocity (V') on normalized flow volume (Q') showed V' = 1.05 Q' - 5.08 (r2 = 0.898).     

CEA治疗伴对侧颈内动脉闭塞的颈动脉重度狭窄的疗效

目的评价颈动脉内膜剥脱术治疗一侧颈内动脉重度狭窄伴对侧颈内动脉闭塞的疗效。方法回顾性分析11例患者的临床资料,包括围手术期并发症及近远期疗效;并比较术前及术后3个月颈部及大脑中动脉血管血流峰值。结果即刻成功率为100%,术后患者脑缺血症状均得到改善,围手术期无病例死亡或缺血性脑卒中等严重并发症发生,仅有1例出现皮下血肿、1例出现短暂声音嘶哑,经积极治疗后均好转。随访率100%,随访时间6~61(32.5±17.2)个月。患者均无术侧颈动脉再狭窄,其中1例再发对侧缺血性脑卒中。术后患者颈动脉血流峰值及大脑中动脉收缩期血流峰值与术前比较差异有统计学意义(均P0.05)。结论对于一侧颈内动脉重度狭窄伴对侧颈动脉闭塞的高危患者,颈动脉内膜剥脱术具有满意的围手术期结果和较好的远期脑卒中预防疗效。