Impairment of blood-brain barrier integrity during carotid surgery as assessed by serum S-100B protein concentrations.

During carotid endarterectomy (CEA) the internal carotid artery is cross-clamped for a period of several minutes. This maneuver may cause cerebral hypoperfusion and/or impairment of the blood-brain barrier (BBB) even in cases where clinical signs are absent. The aim of the present study was to examine whether such alterations could be detected by monitoring the cerebral marker S-100B protein concentrations during and after CEA in the serum. Twenty-five consecutive patients (17 M/8 F, mean age: 64.2 years, range 47-79 years) undergoing elective CEA at our department were studied. All of these patients were without perioperative neurological deficit. Intraoperative samples were collected from internal jugular and peripheral venous blood: 1) before carotid cross-clamping; 2) immediately before declamping; 3) after clamp release. Postoperative samples were taken from peripheral blood at 6 and 24 h, respectively. S-100B was assayed in sera using an immunoluminometric technique. During carotid cross-clamping, S-100B protein concentrations in the ipsilateral jugular serum significantly (p < 0.02) increased to pre-clamp values. After declamping, however, S-100B returned to the baseline level. No differences were seen between the responses of hypertensive and normotensive patients. There was no correlation between carotid occlusion time and S-100B protein concentrations. In the peripheral venous serum no significant changes in S-100B concentrations were detected during or after CEA. We presume that the elevation of S-100B protein concentration during CEA in patients with no neurological deficits indicates the transient opening of the BBB elicited by carotid cross-clamping.     

Delayed carotid shunt occlusion detected by electroencephalographic monitoring

Little has been recorded in the anesthesia literature concerning the changes in the electroencephalogram (EEG) that may occur during carotid endarterectomy many minutes after shunt placement and restoration of flow and that may be attributed to delayed shunt occlusion or cerebral emboli. We describe a patient in whom EEG changes indicative of cerebral ischemia occurred at the time of carotid clamping. The changes resolved promptly after placement of a carotid shunt but recurred 11 minutes later. Because of the EEG changes, the carotid shunt was evaluated and found to have become occluded. EEG monitoring was crucial to the detection of shunt occlusion in the absence of other systemic changes or surgical difficulties. The rapidity and magnitude of the changes in the EEG suggest that, if the occlusion had not been discovered and the patency of the shunt restored, the patient would have been at increased risk for neurologic injury.     

Interference of automated electroencephalographic processing by an endocardial pacemaker

This article reports a patient with an endocardial pacemaker undergoing a carotid endarterectomy in whom cerebral function was monitored by using processed electroencephalography (EEG). The EEG was processed by means of aperiodic analysis. The pacemaker generated an artifact that was identified on the processed EEG display and on the raw EEG display. During the time of carotid cross-clamping, a loss of EEG activity was noted on careful examination of the processed EEG and confirmed by referring to the raw EEG. Nevertheless, because of the presence of the artifact, the activity edge remained essentially constant despite the change in underlying EEG activity. The cross-clamp was released based on the observed change in EEG activity, yielding a return to baseline EEG activity. The surgeon elected to shunt the patient. The patient awoke without neurologic sequelae. This case serves to demonstrate the importance of referring to the raw EEG signal and the limitations of the activity edge in the presence of artifact.     

Interference of automated electroencephalographic processing by an endocardial pacemaker

This article reports a patient with an endocardial pacemaker undergoing a carotid endarterectomy in whom cerebral function was monitored by using processed electroencephalography (EEG). The EEG was processed by means of aperiodic analysis. The pacemaker generated an artifact that was identified on the processed EEG display and on the raw EEG display. During the time of carotid cross-clamping, a loss of EEG activity was noted on careful examination of the processed EEG and confirmed by referring to the raw EEG. Nevertheless, because of the presence of the artifact, the activity edge remained essentially constant despite the change in underlying EEG activity. The cross-clamp was released based on the observed change in EEG activity, yielding a return to baseline EEG activity. The surgeon elected to shunt the patient. The patient awoke without neurologic sequelae. This case serves to demonstrate the importance of referring to the raw EEG signal and the limitations of the activity edge in the presence of artifact.Presented in part at the annual meeting of the Society of Cardiovascular Anesthesiologists, New Orleans, LA, April 1988.     

Carotid endarterectomy for unilateral carotid system transient cerebral ischemia

This study involved 151 consecutive patients who had transient focal cerebral ischemia (TIA) in one carotid arterial system and who had carotid endarterectomy on the side corresponding to the ischemic symptoms. Each patient was examined preoperatively by a neurologist, who also judged the postoperative morbidity and mortality. All patients were operated on by one surgeon. A major or minor ischemic stroke occurred in 3% of patients during operation or within 30 days thereafter. The mortality was less than 1% at 1 month. After the first month, ischemic stroke occurred at a rate of 2% per year, and two-thirds of the strokes were ipsilateral to the endarterectomy. Long-term mortality was 3% per year. Long-term stroke morbidity was less than would have been expected for a comparable group of patients with TIA, and the percentage of deaths due to a cardiac cause was greater than expected, owing to a relative shift from stroke mortality to cardiac mortality. No patient who had a cerebral blood flow of 40 ml or greater per 100 g of brain per minute during occlusion for endarterectomy had a stroke during operation or during 4 1/2 years of follow-up.     

Prospective study of the effectiveness and durability of carotid endarterectomy

In a series of 252 consecutive patients who underwent 282 carotid endarterectomies, we conducted clinical and angiographic follow-up for 2 to 6 years (mean, 3.2 years). Digital subtraction angiography (DSA) was done postoperatively in 95% of cases. Clinical follow-up was achieved in 97% of cases, and DSA follow-up was obtained in 66% of cases. The overall group had a 1% operative minor morbidity (three cases of minimal new neurologic deficit), no major morbidity, and a 0.7% mortality (one death from stroke and one from myocardial infarction). Complications correlated well with the patient's preoperative risk category. During follow-up, 10 minor strokes, only 1 of which was attributable to the reconstructed artery, and 10 transient ischemic attacks, 3 of which were presumably related to recurrent stenosis, occurred. Asymptomatic mild to moderate restenosis of the internal carotid or common carotid artery was identified in 10% of follow-up DSAs and severe stenosis or occlusion in 3%. Stenosis in the opposite common carotid or internal carotid artery progressed in 48 cases (26% of follow-up DSAs and ultrasound studies), and 10 of these became symptomatic. An actuarial analysis of patients who had endarterectomy indicated that the cumulative probability of ipsilateral stroke was 1.5% at 1 month and 2% at 5 years. The cumulative probability of ipsilateral stroke, transient ischemic attack, or reversible ischemic neurologic deficit was 4% at 1 month and 8% at 5 years or less than 1% per year after the first month, with censoring at the time of the second surgical procedure.     

Complications of carotid endarterectomy: the influence of case load

We reviewed the records of 508 consecutive carotid endarterectomies done by 19 surgeons during a five-year period in one medical center to evaluate postoperative complications (stroke and death). Each of 16 surgeons did 32 operations or fewer, with case loads ranging from one to 32. Three surgeons did 70, 98, and 172 respectively. The incidence of stroke among patients of the 16 surgeons combined who did 32 cases or fewer in five years (fewer than ten cases per year) was 7%, with a combined stroke and death rate of 8%; in contrast, patients of the combined surgeons who did more than 32 operations in five years (more than ten cases per year) had a stroke rate of 3%, with a combined stroke and death rate of 3%. When the carotid disease was examined separately, it was apparent that the adverse event rate among patients with asymptomatic or nonhemispheric disease accounted for the difference. Patients of surgeons with fewer cases had 18% adverse events, whereas those of more experienced surgeons had 2% adverse events. The adverse events were similar for both groups in patients with focal transient ischemic attacks or stroke. Seven of the 16 surgeons who did fewer than 32 cases had no patients who had stroke, despite the few carotid endarterectomies they had done. Thus, the stroke rate was somewhat lower in the hands of those surgeons who did endarterectomy more often, but the number of carotid endarterectomies done by a surgeon is not the only factor to decrease the stroke rate. Proper selection of patients and attention to risk factors and technique are essential.     

Preoperative cerebral hemodynamics and shunting during carotid endarterectomy in patients with severe unilateral carotid stenosis

PURPOSE: To estimate the possible predictors for the need for shunting during carotid endarterectomy in patients with severe unilateral carotid stenosis based on preoperative transcranial Doppler sonographic examination. MATERIALS AND METHODS: One hundred twenty-six patients were included in the study. Pulsatility index, flow acceleration, peak systolic velocity, and mean velocity were measured in the middle cerebral artery (MCA) and anterior cerebral artery on both sides. Cerebrovascular reactivity (CVR) was evaluated in 21 patients with shunts and in 55 patients without shunts. RESULTS: The shunted and nonshunted groups did not differ with regard to demographic and clinical characteristics. The side-to-side difference in peak systolic velocity and mean velocity of the MCA was significantly higher in patients with shunts. CVR were significantly higher in the patients without shunts (36.0 +/- 17.2%) than in patients with shunts (16.6 +/- 11.4%; p = 0.0003). The peak systolic velocity and mean velocity asymmetry of the MCA had relatively low receiver operating characteristics, whereas CVR exhibited a relatively high accuracy in predicting the need for shunting. CONCLUSION: Low CVR and increased asymmetry of MCA velocities were found in patients who subsequently required shunting during carotid endarterectomy. The relatively low accuracy of the MCA asymmetry should prevent the use of this criterion as a reliable preoperative predictor for shunting during carotid surgery, whereas CVR was more accurate and may prove useful in this setting.     

The role of surgery in ischemic stroke.

Surgery in the management of stroke is useful primarily as a stroke-preventive measure for patients with extracranial carotid artery occlusive disease. Ideally, lesions that are potential sources of ischemia are removed before a fixed neurologic deficit can occur. Patients with transient ischemic attacks and no deficit or only minor neurologic deficit comprise the largest group of surgical candidates. Diagnostic angiography must be carried out before endarterectomy and should include aortic arch studies of both extracranial and intracranial carotid arteries. Placement of an intra-arterial catheter at the beginning of surgery provides the best method of monitoring arterial pressure. A postoperative angiogram allows visual confirmation of the patency of reconstructed vessels. Such confirmation is particularly important if patients have severely stenotic bilateral carotid artery disease. The surgical mortality for all patients with TIAs is between 1% and 2% in those clinics in which this type of operation is commonly done.     

Contralateral stroke during carotid endarterectomy due to abnormalities in the circle of Willis

Approximately 10-20% of patients will not tolerate cross-clamping of the common carotid artery for carotid endarterectomy procedures. The most frequent causes of neurological deficits are either embolization of particulate matter or cerebral hypoperfusion. Insufficient blood flow through primary collaterals of the circle of Willis is the main reason for hypoperfusion that requires immediate shunt placement. Although excessive preoperative imaging is not indicated in many patients undergoing disobliteration of a stenosed internal carotid artery, there are some patients with particular anatomic constellations who would benefit from a more detailed preoperative work-up. In these cases, the specific risk should be evaluated prior to surgery in order to make plans for appropriate intraoperative management regarding neurologic monitoring and shunt insertion. As regional anesthesia permits early detection of ischemic symptoms, it is advantageous in these patients. We report a case where regional anesthesia allowed early detection of rapidly progressing signs of bi-hemispheric brain ischemia in a patient with diabetes and with at that time unknown severe abnormalities of the circle of Willis. Lack of adequate collateralization was detected only after surgery, in a combined perfusion-magnetic resonance imaging study. In symptomatic diabetics with low-grade stenosis of the internal carotid artery, preoperative assessment of the function of the circle of Willis may therefore be helpful in predicting any increased risk for intraoperative cerebral ischemia.     

Long-term mortality and stroke morbidity after superficial temporal artery-middle cerebral artery bypass operation

Among 239 patients with transient ischemic attacks, mild stroke, or transient monocular visual symptoms who had superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass, no deaths occurred during the operation or within 30 days thereafter. After the first month, mortality on an actuarial basis was 3% per year. Survival at 5 years was 84% in comparison with an expected survival of 89% for persons of comparable age and sex in a general population. Among the 25 deaths that occurred during follow-up, 2 were due to stroke and 16 to cardiac causes. Of 28 strokes that occurred, 5 occurred during operation or that same day, and 3 others occurred within 30 days postoperatively. Thereafter, strokes occurred at the rate of 2.5% per year on an actuarial basis; a third of the strokes occurred contralateral to the surgical site. No difference was found in survival or in survival free of stroke among patients who had proven carotid artery occlusion (N = 157), carotid siphon stenosis (N = 53), or MCA stenosis or occlusion (N = 29). In regard to the probability of stroke, this group of patients compares favorably with population studies of patients with transient ischemic attacks of undetermined cause. When this surgical group was compared with 130 nonsurgical patients who had had ischemic symptoms related to proven internal carotid artery occlusion between 1965 and 1975, however, we could not conclude that the risk of occurrence of stroke was less in patients who had STA-MCA bypass than in the nonsurgical patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

颈动脉内膜剥脱术治疗颈动脉狭窄的临床研究

[目的]探讨颈动脉内膜剥脱术治疗颈动脉狭窄的指证与手术技巧.[方法]回顾分析在2007年6月至2009年5月期间20例颈动脉狭窄患者行颈动脉内膜剥脱术并随访的相关资料.[结果]手术均成功,颈动脉内膜剥脱术1例术后第2天出现脑梗死,3例出现局部淤血,其余未出现明显神经功能障碍.术后平均随访15个月,未有一过性脑卒中或脑梗死发生.[结论]颈动脉内膜剥脱术治疗颈动脉狭窄是安全可靠的,但需要严格掌握手术指证并由技术娴熟的专科医师操作,手术的疗效才能得到保证.     

When to operate in carotid artery disease

Carotid endarterectomy has proved to be beneficial in the prevention of stroke in selected patients. The procedure is indicated in symptomatic patients with carotid-territory transient ischemic attacks or minor strokes who have carotid artery stenosis of 70 to 99 percent. With a low surgical risk, carotid endarterectomy provides modest benefit in symptomatic patients with carotid artery stenosis of 50 to 69 percent. Platelet antiaggregants and risk factor modification are recommended in symptomatic patients with less than 50 percent stenosis. In the Asymptomatic Carotid Atherosclerosis Study, carotid endarterectomy was beneficial in patients who had asymptomatic carotid artery stenosis of 60 percent or greater and whose general health made them good candidates for elective surgery, provided that the arteriographic and surgical complication rates were low. However, in asymptomatic patients, surgery reduced the absolute risk of stroke by only 1 percent per year.     

Heparin-induced thrombocytopenia and thrombosis in ischemic stroke

We reviewed the records of all patients who underwent carotid endarterectomy at our institution during the period from January 1970 through December 1986 to determine the frequency of postoperative occlusions and the role of heparin-induced thrombosis in patients with such occlusions. After 2,527 carotid endarterectomies, a total of 19 occlusions occurred in 18 patients. Of these 18 patients, 6 had an associated heparin-induced coagulation disorder, 3 of whom are described in detail. Although heparin is a useful anticoagulant, it may precipitate occlusion of vessels after an endarterectomy procedure, either at the endarterectomy site or elsewhere. Physicians should be aware of the potentially increased risk for embolic or thrombotic cerebrovascular events in patients who receive heparin therapy.     

Carotid body tumour surgery. A report of seven patients

The purpose of the present paper is to analyse diagnostic and therapeutic aspects of carotid body tumours. Seven patients with carotid body tumour underwent surgery at our department between 1982 and 1998. All of them had an asymptomatic cervical lateral mass. The preoperative evaluation included angiography in 7 patients, duplex scanning in 2 patients and computed tomography in one patient. Tumour excision was performed in 5. Carotid artery resection with the tumour was required in 2 patients and in both, interposition of a 5-mm polytetrafluoroethylene graft was performed. During the resection, temporary carotid shunt was required in one patient. Perioperative transcranial Doppler was used once; the use of a shunt during carotid artery resection was not required in the second case. All tumours were identified as carotid paragangliomas without evidence of malignancy. There was no mortality and no hemiplegia. After surgery, temporary cranial nerve dysfunction was noted in 2 cases. In the follow-up period of 2 to 14 years (mean, 7 years), no recurrent disease occurred. Patency of the grafts was good at 4 and 7 years after carotid artery reconstruction. We conclude that with non-invasive investigation and arteriography it is possible to obtain an early and precise diagnosis. The decision to perform simple tumour excision or additional arterial resection is based on diagnostic preoperative as well as intraoperative evaluation of the individual tumour. As demonstrated in our cases, after resection of the internal carotid artery a polytetrafluoroethylene graft may be used for carotid reconstruction. Early surgery is recommended because it minimises the risk of complications associated with large tumours.     

Anaesthesia and multimodality intraoperative neuromonitoring in carotid endarterectomy. Chronological evolution and effects on intraoperative neurophysiology

Contingency data was retrospectively collected to evaluate the historical and current ability to provide multimodality intraoperative neurophysiological monitoring during carotid endarterectomy under two conditions: total intravenous anaesthesia (TIVA) and low dose halogenated anaesthesia (SEVO). 229 patients were monitored during carotid endarterectomy procedures under general anaesthesia between 2012 and 2020. 121 Patients were monitored with SEVO at a minimum alveolar concentration less than 0.7 and 108 were monitored using TIVA, according to common anaesthetic practice standards in our hospital across the years. Multimodality IONM was established with electroencephalography, somatosensory evoked potentials and motor evoked potentials. As compared to TIVA, patients monitored with SEVO showed significantly higher motor evoked potential thresholds (313.52?±?77.74 SEVO and 218.93 V?±?103.2 V TIVA p?<?0.05) and lower reproducibility. Electroencephalography and somatosensory evoked potentials showed no significant differences among the groups. When using SEVO, multimodality intraoperative neurophysiological monitoring during carotid endarterectomy could mask or miss a motor isolated change in patients in spite of low dose minimum alveolar concentration and of apparently adequate electroencephalography and somatosensory evoked potentials for monitoring. Given these difficulties, we believe the chronological transfer to TIVA could have improved our ability to establish multimodality intraoperative neurophysiological monitoring during carotid endarterectomy in recent times.

     

Comparison of the need for bypass shunt after stroke or transient ischemic attack in 97 patients

Using local anesthesia, we did 97 carotid endarterectomies--48 of them for acute completed stroke, stroke in evolution, or stroke associated with unstable neurologic status, and 49 for transient cerebral ischemic attack. The neurologic status of the awake patients was monitored continuously. Neurologic deterioration resulting from clamping of carotid circulation, and immediate recovery upon release of the clamp indicated need for a bypass shunt. Eighteen of the 48 patients who had had stroke and six of the 49 who had had a transient ischemic attack needed a bypass shunt. The difference was statistically significant (P less than .01).     

踝阵挛试验在脊柱侧凸矫形术中脊髓功能监测的应用价值

目的 :探讨踝阵挛试验在脊柱侧凸矫形手术中脊髓功能监测的应用价值。方法 :对 4 9例脊柱侧凸矫形手术的患者 ,在唤醒试验减浅麻醉时进行踝阵挛试验 ,并与唤醒试验结果相比较。结果 :4 9例患者中 ,4 5例双侧引出踝阵挛 ,1例单侧引出 ,3例双侧均未引出踝阵挛。而所有受试者唤醒试验的结果均为阳性 ,术后亦无脊髓损伤。因此在本观察中 ,踝阵挛试验无真阳性和假阴性结果 ,4例假阳性结果 (8.16 % )。踝阵挛出现的时间明显早于唤醒试验 (P <0 .0 0 1)。结论 :踝阵挛试验对脊柱侧凸矫形术中脊髓功能的监测具有应用价值 ,且出现较早、简单易行 ,应作为常规监测 ,甚至可取代唤醒试验。     

SEVERE HEADACHE AFTER CAROTID ENDARTERECTOMY

SYNOPSIS
A woman developed severe recurrent headache associated with transient neurologic dysfunction while recuperating from carotid endarterectomy performed for transient ischemic attacks. She had severe carotidstenosis preoperatively, but when studied during the period of severe headache had an angiographically normal carotid artery territory. The headaches and neurologic dysfunction appeared after a postoperative headache free period of 72 hours, were self limited, and had characteristics of migraine. Migrainous post-endarterectomy headache may be a manifestation of disordered autoregulation of cerebral blood flow.