颈动脉内膜剥脱术抑或颈动脉支架术: 颈动脉狭窄手术治疗的金标准之争

脑卒中是当今第三大致死病因,是成年人致残的首要原因。颈动脉狭窄是导致缺血性卒中事件发生的最常见原因。20世纪80～90年代已有多个随机对照试验证实颈动脉内膜剥脱术相比于内科药物治疗对于预防卒中具有明显优势。近年来,随着介入技术和器材的不断进步,血管腔内介入治疗愈发成熟,其安全性及有效性正在为一些大规模的临床随机对照试验所证实,腔内介入治疗颈动脉狭窄正在挑战着外科内膜剥脱术的＂金标准＂地位。     

颈动脉内膜切除术和支架植入术的合理选择

颈动脉内膜切除术（CEA）及颈动脉支架植入术（CAS）是目前广泛应用的治疗颅外段颈动脉狭窄的有效手段,由于操作方式、适应人群及围手术期并发症的不同,一直存在关于如何选择治疗方式的争论,笔者就其发展历史和相关临床对照研究结果进行总结。

     

Altered flow territories after carotid stenting and carotid endarterectomy

BACKGROUND: The hemodynamic effects of carotid angioplasty with stent placement (CAS) on the collateral blood supply and on the regional cerebral blood flow (rCBF) have not been established. Recently, arterial spin-labeling (ASL) magnetic resonance imaging (MRI) has been introduced as the first method to quantify the actual territorial contribution of individual collateral arteries as well as to noninvasively measure rCBF. This study investigated alterations in flow territories and rCBF in patients with symptomatic internal carotid artery (ICA) stenosis and compared them with healthy control subjects. In addition, we investigated whether possible differences in flow territories and rCBF were present between patients undergoing CAS and patients undergoing carotid endarterectomy (CEA). METHODS: The study included 24 consecutive patients (15 men and 9 women; age 67+/-9 years) with symptomatic ICA stenosis. CAS was performed in 12 patients, and 12 patients underwent CEA. Flow territory mapping and rCBF measurements were performed with ASL MRI before intervention and 1 month after. The control group consisted of 40 subjects (25 men and 15 women; age 67+/-8 years). RESULTS: The flow territory of the ipsilateral ICA in patients with ICA stenosis was smaller, and the territories of the contralateral ICA and vertebrobasilar arteries were larger compared with control subjects (P<.05). After CAS, rCBF in the ipsilateral hemisphere increased from 60.2+/-16.9 mL/(min.100 g) to 68.9+/-9.2 mL/(min.100 g) (P<.05). Differences in flow territories and rCBF between patients and control subjects disappeared after CAS. Changes in flow territories and rCBF were similar in patients who underwent CAS or CEA. CONCLUSIONS: CAS results in a normalization of the territorial distribution and rCBF, as assessed by ASL MRI. The degree of improvement is similar to that seen after CEA.     

Carotid artery stenting after carotid endarterectomy

Atherosclerotic carotid artery disease remains an important cause of cerebrovascular ischemic disease. We present a patient with residual stenosis of the distal internal carotid artery following carotid endarterectomy that was treated with stenting. The case highlights the potential complimentary benefits of carotid endarterectomy and carotid stenting.     

颈动脉内膜剥脱术和颈动脉支架的客观评述

自1954年Eastcott完成首例颈动脉内膜剥脱手术(CEA)以来,已有50多年的历史,但初期并没有得到人们的认同和接受.直至20世纪90年代初,欧美国家进行了一系列关于颈动脉狭窄治疗的前瞻性临床研究,包括对于有症状和无症状颈动脉狭窄以及中度和重度颈动脉狭窄的前瞻性临床研究,证实颈动脉内膜剥脱术是一种安全有效的方法,治疗效果优于药物治疗,可以使有症状或无症状的中、重度颈动脉狭窄患者获益,多年来一直被认为是治疗颈动脉狭窄、预防卒中的金标准.     

颈动脉狭窄手术及介入治疗的围术期管理

背景 脑卒中是造成人类死亡的主要原因之一.15％～20％的缺血性脑血管病归因于颈动脉狭窄或闭塞,颈动脉内膜剥脱术(carotid endarterectomy,CEA)和颈动脉血管腔内球囊成形及支架植入术(carotid angioplasty and stenting,CAS)对预防缺血事件发生有效,但围手术期卒中、死亡等并发症对围术期管理提出挑战. 目的 对颈动脉狭窄手术及介入治疗围术期管理进行综述. 内容 重点阐述CEA和CAS围术期危险因素控制、术前评估、麻醉方法与管理、术中神经功能监测和脑保护. 趋向 积极谨慎的围术期管理是保证颈动脉狭窄患者围术期脑氧供需平衡、降低围术期并发症的有效措施.     

Hemodynamic instability after extracranial carotid stenting

Summary Objective. Hemodynamic instability (hypertension, hypotension and bradycardia) is a well-known complication of carotid endarterectomy. Carotid angioplasty and stenting (CAS) is becoming a valuable alternative treatment for patients with severe carotid stenosis and increased surgical risk. CAS implies instrumentation of the carotid bulb, so baroceptor dysfunction may provoke hemodynamic instability. The aim of this work was to calculate the incidence of this complication and to detect factors to predict it. Methods. Medical records and angiograms of 51 consecutive patients submitted to CAS for severe atherosclerotic stenosis (40 cases) or postsurgical restenosis (11 cases) were retrospectively reviewed in order to detect the occurrence of intra- and post-procedural hypertension (systolic blood pressure >160 mmHg), hypotension (systolic blood pressure <90 mmHg) and bradycardia (heart rate <60 beats/min). The relationship between clinical, procedural and angiographic factors and the occurrence of hemodynamic instability was assessed with univariate and multivariate analysis (logistic regression). Results. Transient mild systolic post-procedural hypertension occurred in five cases (10%); preprocedural hypertension, asymptomatic stenosis and ipsilateral post-surgical restenosis predicted this. Hypotension with bradycardia also occurred in five cases (10%), one with neurological sequelae. Transient periprocedural bradycardia occurred in 19 cases (37%). Severe bradycardia without hypotension arose in one case only. Factors predicting post-procedural hypotension included the presence of a fibrous plaque and the ratio between the pre- and post-stenting diameter of the internal carotid artery. Peri-procedural bradycardia predicted post-procedural bradycardia. None of these factors were confirmed by multivariate analysis as a significant prognostic predictor. Conclusion. Mild systolic hypertension may occur after CAS, but is resolved by medical treatment. Prolonged hypotension and bradycardia may also arise and this can be dangerous because it may cause neurological deterioration due to hypoperfusion. These complications cannot be predicted by clinical, procedural, and angiographic factors.     

Clinical results of carotid artery stenting compared with carotid endarterectomy

OBJECTIVES: Carotid artery stenting (CAS) is an alternative to carotid endarterectomy (CEA) for treating carotid artery stenosis. We conducted a systematic review and meta-analysis of the clinical trials to date comparing these two procedures to determine their relative safety and efficacy. METHODS: Searches of the Cochrane Controlled Trials Register, MEDLINE, and EMBASE identified two cohort studies and eight randomized, controlled trials (RCTs) comparing CEA and CAS. Meta-analysis was performed for the primary outcome of 30-day stroke or death, using an intention-to-treat analysis. Between-trial heterogeneity was assessed using the chi2 test, and fixed-effects models were used to pool estimates in the absence of heterogeneity. Meta-regression was conducted to investigate potential effect differences by patient, intervention, and trial characteristics. To evaluate the effect of study design and inclusion criteria, sensitivity and subgroup analyses were performed. RESULTS: Ten trials encompassing 3580 patients were analyzed. Patients who underwent CAS had a higher risk of 30-day stroke/death relative to patients who underwent CEA (risk ratio [RR], 1.30; 95% CI, 1.01-1.67). Meta-analysis and meta-regression demonstrated no between-trial heterogeneity. Sensitivity analysis of only RCTs showed similar higher risk for stroke/death (RR, 1.38; 95% CI, 1.06-1.79) in CAS patients. Subgroup analysis of trials enrolling only symptomatic patients showed higher risk of 30-day stroke/death (RR, 1.63; 95% CI, 1.18-2.25), but trials enrolling both symptomatic and asymptomatic patients showed no significant differences (RR, 0.89; 95% CI, 0.59-1.35). CONCLUSIONS: Meta-analysis of trials to date shows CAS is associated with higher 30-day risk of stroke/death compared with CEA. Thus, for the patient at average surgical risk, the role of CAS is unproven, especially for symptomatic patients. And for the patient at high surgical risk, the role of any intervention is uncertain in the setting of competing comorbidities. The results of ongoing clinical trials in this area will likely provide additional evidence to support treatment choices for carotid artery stenosis.     

Hemodynamic benefits of regional anesthesia for carotid endarterectomy

OBJECTIVE: The objective of this study was to define differences in perioperative hemodynamics and associated outcomes in patients who undergo carotid endarterectomy (CEA) with regional and general anesthesia. METHODS: All the patients who underwent CEA during a 25-month period were reviewed, with a comparison of those who underwent operation with cervical block anesthesia (CB) with those who underwent operation with general anesthetic (GA). Baseline intraoperative and postoperative blood pressure and heart rate were recorded, and deviation from initial values was calculated. The administration of vasoactive medications was assessed. Operative time, intensive care unit admission, postoperative length of stay, and cardiac/neurologic morbidity were recorded. RESULTS: From October 16, 1998, to December 1, 2000, 550 nonemergent CEAs were performed in 527 patients (226 with CB and 324 with GA). The patients in both groups were similar in age, presentation, and associated comorbidities. Although baseline blood pressure and heart rates were similar in both groups, those patients who underwent operation with GA had significantly greater intraoperative and postoperative hemodynamic variability and received more vasoactive medications during surgery (87% versus 51%; P <.001) and in the recovery room (36% versus 21%; P =.0009). Major postoperative blood pressure derangements were more common in the GA group (18% versus 10%; P <.05). Patients who underwent operation with GA more frequently needed intensive care unit admission (16% versus 7%; P =.01) and had more frequent delays in discharge (20% versus 11%; P =.008; postoperative length of stay, 2.1 versus 1.6 days; P =.01). Although no difference was seen in neurologic morbidity rates between groups (combined major stroke/death rate, 1.8%), the major cardiac morbidity rate was noted to be lower in the CB group (1% versus 4%; P =.05). The total in-room time was shorter in the CB group (108 versus 122 minutes; P <.001). CONCLUSION: CEA performed with CB is associated with significantly less perioperative hemodynamic instability than with GA. This results in fewer major adverse cardiac events. Ultimately, decreased critical care resource use is realized as is a shortened length of stay.     

Noninvasive investigation of autonomic activity after carotid stenting or carotid endarterectomy

OBJECTIVE: Carotid artery stenting (CAS) has been introduced as an alternative to carotid endarterectomy (CEA) for the treatment of carotid artery stenosis. Both techniques seem to be associated with postoperative hemodynamic lability. Both may induce baroreceptor dysfunction, possibly leading to transient impairment of cardiovascular autonomic activity and resulting in hemodynamic instability. This instability might contribute to postoperative morbidity. To elucidate these phenomena, we studied the cardiac baroreflex and autonomic cardiovascular control after CAS and CEA. METHOD: In 20 patients scheduled for CAS (n = 10) or CEA (n = 10), intra-arterial pressures and electrocardiograms were recorded during 10 minutes before and 8 and 24 hours after the procedure. Spontaneous cardiac baroreflex sensitivity was assessed using the sequence method and cross-spectral analysis. In addition, cardiovascular autonomic activity was investigated using spectral analysis of heart rate variability and systolic arterial pressure variability. RESULTS: After CAS, we demonstrated an increase of the spontaneous baroreflex sensitivity median (interquartile range) from 5.6 (5.1 to 6.2) ms/mm Hg before the procedure to 8.8 (6.8 to 10.5) ms/mm Hg and 7.7 (3.9 to 8.6) ms/mm Hg (P < .001), 8 and 24 hours after the procedure. This was consistent with the increase of the high frequency component of heart rate variability reflecting cardiac parasympathetic activity and a decrease of the low frequency of systolic arterial pressure variability reflecting sympathetic vascular activity. The postoperative period was also associated with decreased systolic arterial pressure from 173 (162 to 190) mm Hg at baseline to 122 (109 to 143) mm Hg and 136 (121 to 143) mm Hg at 8 and 24 hours after CAS (P < .001). No changes in baroreflex sensitivity or in autonomic activity were observed after CEA. CONCLUSIONS: These preliminary data suggest that CAS is associated with parasympathetic predominance postoperatively and may probably explain the lower systolic arterial pressure observed after CAS.     

A comparative analysis of long-term mortality after carotid endarterectomy and carotid stenting

Background

The value of carotid intervention is predicated on long-term survival for patients to derive a stroke prevention benefit. Randomized trials report no significant difference in survival after carotid endarterectomy (CEA) vs carotid artery stenting (CAS), whereas observational studies of “real-world” outcomes note that CEA is associated with a survival advantage. Our objective was to examine long-term mortality after CEA vs CAS using a propensity-matched cohort.

Eversion carotid endarterectomy for recurrent stenosis after carotid angioplasty/stenting

Restenosis requiring treatment after carotid angioplasty/stenting is uncommon in clinical practice. Treatment options include repeat angioplasty (with or without another stent) or carotid endarterectomy. This report describes a patient with recurrent stenosis treated with eversion carotid endarterectomy and stent removal.     

Comparative assessment of the results of open carotid endarterectomy and carotid aftery stenting

A comparative study of 48 carotid stent grafting and 23 open carotid endarterectomies was carried out. Patients of both groups were comparable by cerebrovascular insufficiency degree and concomitant diseases. General rate of complications after carotid stent grafting (CSG) was 5.1%. There was a small ischemic stroke with right-sided hemiparesis and aphasia in one patient during CSG. Complete regress of the neurological symptoms was seen on the 5th day. In the nearest postoperative period after CSG there was a big ischemic stroke in the territory of MCA in one patient. Rate of complications after open carotid endarterectomy (OCEAE) was 8.7% Transient ischemic attacks were seen in 2 patients in early postoperative period. Paresis of the IX cranial nerves was in one patient. In long-term postoperative period after CSG 2 patients died due to cardiac causes. One patient died 18 months after OCEAE due to ischemic stroke. In long-term period after OCEAE restenosis of the internal carotid artery was seen in 4.5% cases, while there were no restenosis after CSG. It is concluded that CSG is an effective method of treatment of carotid stenosis with lower lethality and postoperative complications rate compared with OCEAE. Indications for CSG are symptomatic stenosis of ICA (>60%), asymptomatic stenosis of ICA(>70%), two-sided lesions of the carotid arteries, carotid stenosis with lesions of other brachiocephalic arteries, insufficiency of Willis circle.     

Intrapatient comparison of restenosis between carotid artery angioplasty with stenting and carotid endarterectomy

AIM: Comparison of restenosis in patients who underwent both carotid artery angioplasty with stenting (CAS) and contralateral carotid endarterectomy (CEA). METHODS: From our CAS data registry (1998-present) all patients with a history of contralateral CEA at any other time were selected (n = 63). Mean age was 70.6, SD = 6.8 for CAS and 68.2, SD = 6.1 for CEA and symptomatic carotid artery stenosis was present in 24% of patients pre-CAS and 40% pre-CEA. All CEAs were primary interventions, 19% of CAS were secondary to restenosis after previous ipsilateral CEA. All patients were followed up prospectively with duplex at 1 year (CAS: n = 58, CEA: n = 59), 2 years (CAS: n = 44, CEA: n = 53), 3 years (CAS: n = 27, CEA: n = 41), and every year thereafter. Within each patient we compared restenosis (>50%) between CAS and CEA procedures. RESULTS: After a follow-up of 28.7 months for CAS (SD = 16.9) and 54.4 months for CEA (SD = 39.5) the rate of = or > 50% restenosis for CAS vs CEA at 1, 2, and 3 years was 23% vs 10%; 31% vs 19%; and 34 vs 24%, respectively (log rank P = NS). CONCLUSIONS: Our intrapatient comparison of patients who underwent both CAS and contralateral CEA did not reveal significant difference in restenosis between both procedures.     

Hemodynamic status following regional and general anesthesia for carotid endarterectomy

We prospectively studied 23 patients undergoing carotid endarterectomy under regional (n = 13) or general (n = 10) anesthesia to determine the hemodynamic basis of increased frequency in the need for postoperative vasopressor support when regional anesthesia was used. Anesthesia and postoperative care were conducted without reference to hemodynamic data from pulmonary artery catheterization. Although mean arterial pressure was similar in the two groups postoperatively, 11 of the 13 patients undergoing regional anesthesia and 3 of the 10 patients undergoing general anesthesia required phenylephrine postoperatively. No patient required therapy postoperatively to reduce a systolic pressure exceeding 160 mm Hg. Mean arterial pressure remained below the preoperative baseline value in both groups (p < 0.05 with general anesthesia; p = 0.06 with regional anesthesia) during follow-up. In the general anesthesia group, systemic vascular resistance declined significantly below baseline (p < 0.05) following the operation, accompanied by a decline in mean arterial pressure (p < 0.05) and a higher cardiac output. Intraoperative fluid requirements were greater during general anesthesia than during regional anesthesia (p < 0.01). Pulmonary artery occlusion pressure was lower postoperatively than at baseline in both groups (p < 0.05). Pulmonary artery occlusion pressure was higher in the general anesthesia group despite the greater use of phenylephrine in the regional anesthesia group.     

The effect of statin medications on perioperative and long-term outcomes following carotid endarterectomy or stenting

Statins belong to a class of drugs known to inhibit 3-hydroxy 3-methylglutaryl coenzyme A reductase, and block hepatic cholesterol synthesis. Since the initial statin was approved by the Food and Drug Administration in 1987, these agents quickly became the gold standard for treatment of hypercholesterolemia. Effective lipid-lowering has been found to improve the long-term prognosis of patients with coronary artery disease. In addition, statins have also been found to be highly effective in primary and secondary stroke prevention among medically managed patients with cardiovascular disease, and it appears that this benefit is largely due to the non-cholesterol-lowering, so-called pleiotropic, effects of statins. During the past decade, agents such as beta-blockers, aspirin, or other antiplatelet medications have proven to reduce the incidence of adverse postoperative outcomes among vascular surgical patients, and have rightfully assumed a place in our overall therapeutic armamentarium. There is growing evidence that statins may be especially effective in reducing cardiovascular morbidity and improving outcomes after major vascular surgery. A recent study from Johns Hopkins Hospital demonstrated a threefold reduction in the rate of perioperative stroke (P < .05) and fivefold reduction of perioperative mortality (P < .05) among 1,566 patients undergoing carotid endarterectomy (CEA). This benefit was confirmed in a series of 3,360 CEAs performed at multiple hospitals throughout Western Canada. Statin use was independently associated with a 75% reduction (odds ratio [OR] = 0.25; 95% confidence interval [CI], 0.07-0.90) in the odds of death and 45% reduction (OR = 0.55; 95% CI, 0.32-0.95) in the odds of ischemic stroke or death among patients with symptomatic carotid disease. Further, there is some data indicating that statin use may reduce long-term incidence of restenosis following CEA. Preliminary work indicates that a similar benefit of statin use in reducing neurologic morbidity among patients undergoing carotid angioplasty and stent procedures. A number of the pleiotropic effects of statin medications may be responsible for these clinical observations. Further work is necessary to better elucidate these mechanisms, as well as to determine the optimal agents, dosing, and timing of drug administration among patients undergoing carotid interventions.