Causes of the increased stroke rate after carotid endarterectomy in patients with previous strokes

The effect of the collateral cerebrovascular circulation on tolerance to carotid artery cross-clamping and on early outcome after carotid endarterectomy

OBJECTIVE

The Circle of Willis (CoW) serves as the primary source of contralateral blood supply in patients who undergo carotid artery cross-clamping (CC) for carotid endarterectomy (CEA). It has been suggested that the CoW's anatomy influences CEA outcomes. The aim of this study was to evaluate associations between the cerebral collateral circulation, a positive awake test for intraoperative neurologic deficit after carotid CC, and postoperative adverse neurologic events.

METHODS

A systematic review was conducted searching MEDLINE, Cochrane, and Web of Science databases for studies that assessed the cerebral circulation, including CoW variations, using neuroimaging techniques in patients who underwent carotid CC. For the metanalytical incidence, the statistical technique used was weight averaging. Otherwise, descriptive analysis was used due to the excessive heterogeneity of the studies.

RESULTS

Eight publications, seven cohort and one case-controlled study, involving 1313 patients who underwent carotid artery CC under loco-regional anesthesia, were included in the systematic review. The incidence of positive awake test in the cohort studies ranged from 4.4% to 19.7%. Carotid artery CC resulted in positive awake test in 5% to 91% of patients with alterations in the anterior portion and in 27% to 74% with alterations in the posterior portion of the CoW. A positive awake test in patients with contralateral carotid stenosis or occlusion ranged from 5.8% to 45.7%. Contralateral carotid stenosis >70% or occlusion were associated with a positive awake test (P < .001). Patients with incomplete CoW did not have statistically significant correlation with intraoperative neurological deficits after CC. Data were insufficient to evaluate the effect of the collateral circulation on early outcome after CEA.

CONCLUSIONS

In this systematic review, contralateral carotid artery stenosis or occlusion, but not CoW abnormalities, were associated with a positive awake test after carotid artery CC. Further research is needed to evaluate which specific CoW anomaly predicts neurologic deficit after CC and to confirm association between a positive awake test and clinical outcome after CEA.

Timing of carotid endarterectomy after recent minor to moderate stroke

OBJECTIVE

Early carotid endartectomy is generally favored by vascular surgeons in patients after a minor to moderate stroke. Herein, we compared the results of early versus delayed carotid endartectomy in patients presenting with similar National Institutes of Health Stroke Scale findings after a recent minor to moderate stroke.

METHODS

A retrospective analysis of 101 patients undergoing carotid endartectomy after a recent stroke in the distribution of the branches of the middle cerebral artery with >70% internal carotid artery stenosis from 2000 to February 2018 was performed.

RESULTS

Sixty patients had carotid endartectomy within 2 weeks (group A) and 41 had carotid endartectomy within 2-8 weeks of stroke (group B). Associated factors, such as coronary artery disease, hypertension, diabetes mellitus, hyperlipidemia, nicotine abuse, chronic obstructive pulmonary disease, and renal failure, were similar in both groups. However, there was preponderance of male patients in group B (0.01). In group A, 35 patients presented with minor stroke (National Institutes of Health Stroke Scale 1-4) and 25 had a moderate stroke (National Institutes of Health Stroke Scale 5-15). In group B, 21 had a minor stroke and 20 had a moderate stroke (P = .54). Perioperative stroke occurred in 4 patients in group A and none in group B (P = .14), with perioperative stroke and death rate of 4.0%. Postoperative seizures occurred in 1 patient in group A and three in group B (P = .30).

CONCLUSION

Early as well as delayed carotid endartectomy in patients with minor to moderate stroke results in a satisfactory outcome. To prevent recurrent stroke in the waiting period, early carotid endartectomy should be preferred.

Perioperative stroke

It is increasingly recognized that one can identify a higher risk patient for perioperative stroke. The risk of stroke around the time of operative procedures is fairly substantial and it is recognized that patients initially at risk for vascular events are those most likely to have this risk heightened by invasive procedures. Higher risk patients include those of advanced age and there is a cumulative risk, over time, of coexistent hypertension, atherosclerosis, diabetes mellitus, cardiac disease and clotting disorders. There are a number of possible mechanisms associated with the procedure (e.g., preoperative hypercoagulability, holding of antithrombic therapy at the time of the procedure and cardiac arrhythmia) that can promote a thrombo-embolic event. Examples of these include: direct mechanical trauma to extracranial vessels related to operations on the head and neck; and vascular injury as a consequence of vascular and innovative endovascular procedures affecting the cerebral circulation (e.g., carotid endarterectomy, extracranial or intracranial angioplasty with stenting, and use of the MERCI clot retrieval device), as well as various endovascular methods that have been developed to obliterate cerebral aneurysms and arteriovenous malformations as an alternative to surgical clipping and surgical resection, respectively.

The impact of smoking on neurosurgical outcomes

Cigarette smoking is a common health risk behavior among the general adult population, and is the leading preventable cause of morbidity and mortality in the US. The surgical literature shows that active tobacco smoking is a major risk factor for perioperative morbidity and complications, and that preoperative smoking cessation is an effective measure to lower these risks associated with active smoking. However, few studies have examined the effects of smoking and perioperative complications following neurosurgical procedures. The goal of this review was to highlight the scientific data that do exist regarding the impact of smoking on neurosurgical outcomes, to promote awareness of the need for further work in the specific neurosurgical context, and to suggest ways that neurosurgeons can promote smoking cessation in their patients and lead efforts nationally to emphasize the importance of preoperative smoking cessation. This review indicates that there is limited but good evidence that smoking is associated with higher rates of perioperative complications following neurosurgical intervention. Specific research is needed to understand the effects of smoking and perioperative complications. Neurosurgeons should encourage preoperative smoking cessation as part of their clinical practice to mitigate perioperative morbidity associated with active smoking.

Urgent Carotid Endarterectomy for Patients with Unstable Symptoms: Systematic Review and Meta-Analysis of Outcomes

Current evidence suggests that carotid endarterectomy (CEA) performed within 2 weeks of symptoms produces better long-term results than if it is delayed. Urgent endarterectomy following unstable presentations such as crescendo transient ischemic attack (cTIA) or progressive stroke has been associated with variable results. The evidence for this treatment strategy required reviewing. A systematic review of articles related to urgent CEA between 1980 and 2008 was performed. For cTIA, there was an odds ratio of 5.6 (95% confidence interval 3.3–9.7, p ≤ .0001) for combined stroke or death compared with surgery for “standard” indications. For unstable stroke, the odds ratio was 5.5 (95% confidence interval 3.1–9.3, p ≤ .0001). Patients with unstable neurologic presentations are at higher risk of complications if operated on urgently. Clearer definitions would help more precise patient selection to avoid inadvertently operating on patients with an unacceptably high risk of poor outcome.

INTRAOPERATIVE NEUROLOGICAL CHANGES IN 1665 REGIONAL ANAESTHETIC CAROTID ENDARTERECTOMIES PREDICTS POSTOPERATIVE STROKE

BACKGROUND

To maximize the benefit of carotid endarterectomy (CEA) in stroke prevention its complication rate must be minimized. The purpose of this study was to report the outcomes of a large series of CEA carried out under regional anaesthesia with selective shunting, with particular emphasis on identifying predictors for perioperative stroke and mortality.

METHODS

Between 1987 and 2003 the data for 1665 consecutive regional anaesthetic CEA carried out in 1495 patients were collected prospectively; awake neurological testing facilitated selective shunting. Preoperative data, intraoperative events and postoperative in-hospital complications were recorded and analysed.

RESULTS

There were 38 non-fatal strokes (2.3%) and 10 deaths (0.6%), giving a combined stroke and mortality rate of 2.9%. Only patients who needed shunting were found to have significantly higher rate of postoperative stroke and mortality (7.0 vs 1.9%, P < 0.001). Patient characteristics, comorbidities, indication for operation (P = 0.34) and the degree of stenosis of the contralateral carotid artery (P = 0.65) were not found to be predictive of perioperative stroke or mortality, although the latter two were found to be predictive of the need for shunting (P < 0.001 and P = 0.002).

CONCLUSION

Regional anaesthetic CEA is a safe and effective technique with excellent morbidity and mortality rates. The technique can be undertaken safely regardless of the indication for endarterectomy or the status of the contralateral carotid artery. Patients who developed intraoperative neurological changes requiring shunting are identified as high risk for perioperative stroke or mortality and should therefore be carefully monitored postoperatively.

Risk Estimates of Stroke After Coronary Artery Bypass Graft and Carotid Endarterectomy

Neurologic complications of cardiovascular surgeries are well documented in the literature. Neurologic deficits may be mild and reversible or may be associated with permanent neurologic deficit. The incidence and severity of such complications vary according to the type of surgical procedure and usually correlate with patients' preoperative general medical condition, duration of surgeries, and intraoperative complications.

Early carotid endarterectomy in symptomatic patients is associated with poorer perioperative outcomes

OBJECTIVE

The optimal timing of carotid endarterectomy (CEA) after ipsilateral hemispheric stroke is controversial. Although early studies suggested that an interval of about 6 weeks after a completed stroke was preferred, more recent data have suggested that delaying CEA for this period of time is not necessary. With these issues in mind, we reviewed our experience to examine perioperative outcome with respect to the timing of CEA in previously symptomatic patients.

METHODS

A retrospective review of a prospectively maintained database of all CEAs performed at our institution from 1992 to 2003 showed that 2537 CEA were performed, of which 1,158 (45.6%) were in symptomatic patients. Patients who were operated on emergently <or=48 hours of symptoms for crescendo transient ischemic attacks (TIAs) or stroke-in-evolution were excluded from analysis (n = 25). CEA was considered "early" if performed <or=4 weeks of symptoms, and "delayed" if performed after a minimum of a 4-week interval following the most recent symptom.

RESULTS

Of nonurgent CEAs in symptomatic patients, in 87 instances the exact time interval from symptoms to surgery could not be precisely determined secondary to the remoteness of the symptoms (>18 months), and these were excluded from further analysis. Of the remaining 1,046 cases, 62.7% had TIAs and 37.3% had completed strokes as their indication for surgery. Among the entire cohort, patients who underwent early CEA were significantly more likely to experience a perioperative stroke than patients who underwent delayed CEA (5.1% vs 1.6%, P = .002). Patients with TIAs alone were more likely to be operated on early rather than in a delayed fashion (64.3% vs 46.7%, P < .0001), likely reflecting institutional bias in selecting delayed CEA for stroke patients. However, even when examined as two separate groups, both TIA patients (n = 656) and CVA patients (n = 390) were significantly more likely to experience a perioperative stroke when operated upon early rather than in a delayed fashion (TIA patients, 3.3% vs 0.9%, P = .05; CVA patients, 9.4% vs 2.4%, P = .003). There were no significant differences in demographics or other meaningful variables between patients who underwent early CEA and those who underwent delayed CEA.

CONCLUSIONS

In a large institutional experience, patients who underwent CEA <or=4 weeks of ipsilateral TIA or stroke experienced a significantly increased rate of perioperative stroke compared with patients who underwent CEA in a more delayed fashion. This was true for both TIA and stroke patients, although the results were more impressive among stroke patients. On the basis of these results, we continue to recommend that waiting period of 4 weeks be considered in stroke patients who are candidates for CEA.

Safety of carotid endarterectomy in 2,443 elderly patients: lessons from nonagenarians--are we pushing the limit?

BACKGROUND

Elderly patients are a rapidly expanding segment of the population. Recent studies suggest that octogenarians have mortality and morbidity after carotid endarterectomy (CEA) similar to that in their younger cohort. Outcomes of CEA performed in nonagenarians have not been commonly reported; this study seeks to determine the safety of CEA in nonagenarians in general practice.

STUDY DESIGN

All patients in nonfederal Connecticut hospitals undergoing CEA between 1990 and 2002 were identified using the state discharge database (Chime Inc; ).

RESULTS

A total of 14,679 procedures were performed during the 12 study years. Sixty-four patients were nonagenarians (0.4%). Perioperative mortality was higher among nonagenarians (3.1%) compared with younger patients, including the 2,379 octogenarians (0.6%; p = 0.008, chi-square; odds ratio = 9.1, p = 0.006). No statistically significant difference was noted in perioperative stroke rates between nonagenarians (3.1%) and octogenarians (1.2%; p = 0.35, chi-square; odds ratio 2.3, p = 0.28). Nonagenarians had longer hospital lengths of stay (7.3 days, p < 0.0001), intensive care unit lengths of stay (1.2 days, p = 0.0013), and greater hospital charges ($17,967 +/- $1,907, p < 0.0001) than younger patients. Nonagenarians underwent operative procedures more frequently in an emergent setting (22%) compared with octogenarians (11%, p < 0.001) and had a greater percentage of symptomatic presentations (stroke: 14% versus 11%, p = 0.04; transient ischemic attack: 8% versus 5%, p = 0.04, respectively). All perioperative deaths and strokes occurred in symptomatic nonagenarians (15% versus 0%, p = 0.038; 15% versus 0%, p = 0.038; respectively).

CONCLUSIONS

Carotid endarterectomy is performed in nonagenarians, as a group, with greater rates of perioperative mortality and morbidity than in younger patients, including octogenarians. But nonagenarians have a greater rate of symptomatic and emergent presentations than younger patients, which may account for their increased mortality, morbidity, length of stay, and incurred charges. Asymptomatic nonagenarians have similar outcomes after carotid endarterectomy compared with younger patients, including octogenarians, with low rates of mortality and morbidity.

Early versus delayed carotid endarterectomy after a nondisabling ischemic stroke: a prospective randomized study

BACKGROUND

Although many retrospective and a few prospective studies have analyzed the outcome of early and delayed carotid endarterectomy (CEA) after a recent minor or nondisabling stroke (ie, a minimal and stabilized focal neurologic deficit of acute onset persisting for more than 24 hours and not leading to a handicap or to a significant impairment of daily living activities), the optimal timing of surgery remains uncertain. The purpose of this study was to prospectively compare the perioperative death and stroke rates of CEA performed within 30 days (early group) or more than 30 days (delayed group) after a nondisabling ischemic stroke in patients with carotid bifurcation disease.

METHODS

During a 4-year period, of 86 patients experiencing a minor stroke, 45 were randomized to undergo early CEA and 41 to undergo delayed CEA. All patients underwent preoperative cerebral computed tomography, duplex ultrasonographic scanning and angiography of the supra-aortic trunks. All CEAs were carotid eversion endarterectomies and were performed by the same surgeon, using deep general anesthesia, with continuous electroencephalographic monitoring for the selective shunting. The perioperative death and stroke rates were compared between the 2 groups.

RESULTS

No perioperative deaths occurred in either group. No recurrent strokes occurred during the waiting period in the delayed group. The incidence of perioperative stroke was comparable in the 2 groups (1 of 45, 2% vs 1 of 41, 2%). The mean follow-up was 23 months (range, 6 to 50 months). Survival rates after 1, 2, and 3 years were similar in the 2 groups.

CONCLUSIONS

Early CEA after a nondisabling ischemic stroke can be performed safely with perioperative mortality and stroke rates comparable with those of delayed CEA. The timing of surgery does not seem to influence the benefit of the CEA.

Risk modelling study for carotid endarterectomy

BACKGROUND

The aims of this study were to identify factors that influence the risk of stroke or death following carotid endarterectomy (CEA) and to develop a model to aid in comparative audit of vascular surgeons and units.

METHODS

A series of 839 CEAs performed by four vascular surgeons between 1992 and 1999 was analysed. Multiple logistic regression analysis was used to model the effect of 15 possible risk factors on the 30-day risk of stroke or death. Outcome was compared for four surgeons and two units after adjustment for the significant risk factors.

RESULTS

The overall 30-day stroke or death rate was 3.9 per cent (29 of 741). Heart disease, diabetes and stroke were significant risk factors. The 30-day predicted stroke or death rates increased with increasing risk scores. The observed 30-day stroke or death rate was 3.9 per cent for both vascular units and varied from 3.0 to 4.2 per cent for the four vascular surgeons. Differences in the outcomes between the surgeons and vascular units did not reach statistical significance after risk adjustment.

CONCLUSION

Diabetes, heart disease and stroke are significant risk factors for stroke or death following CEA. The risk score model identified patients at higher risk and aided in comparative audit.

Causes of perioperative stroke after carotid endarterectomy: special considerations in symptomatic patients

In order to maximize the efficacy of carotid endarterectomy (CEA), the rate of perioperative stroke must be kept to a minimum. A recent analysis of carotid surgery at our institution found that most perioperative strokes were due to technical errors resulting in thrombosis or embolization. From 1992 through 1997 we have performed nearly 1200 additional CEAs; the purpose of this study was to examine recent trends in the causes of perioperative stroke, with specific attention to differences in symptomatic and asymptomatic patients. The records of 1041 patients undergoing 1165 CEAs were reviewed from a prospectively compiled database. Analysis of these data showed that a history of preoperative stroke appears to increase the risk of perioperative stroke after CEA. Surgical factors associated with perioperative stroke include an inability to tolerate clamping, use of an intraarterial shunt, and having surgery performed under general anesthesia; these factors are clearly interrelated and only the use of intraarterial shunting remains a risk factor by multivariate analysis. Over half of all perioperative strokes (54%) appear to be caused by intraoperative or postoperative thrombosis and embolization. The patient requiring use of intraarterial shunting and/or with a preoperative stroke most likely has a significant watershed area of brain at increased risk of infarction. However, technical errors are still the most common cause of perioperative stroke in these high-risk patients. Such high-risk patients may manifest clinical stroke from small emboli that may be tolerated by asymptomatic clamp-tolerant patients. Technical precision and appropriate cerebral protection are particularly critical for successful outcomes in high-risk patients.

Carotid endarterectomy in an awake patient with contralateral carotid occlusion: influence of selective shunting

The objectives of this study were to determine whether the presence of a contralateral carotid occlusion increases risk and whether the perioperative results are influenced by a systematic or selective policy of shunting during carotid endarterectomy (CEA) in an awake patient. In a retrospective study we compared patients with and without contralateral carotid occlusion (group I, n = 198 - group II, n = 1068) who required CEA. In 77 patients of group I, a shunt was systematically adopted (subgroup A); in the other 121 patients (subgroup B) and in all patients of group II a selective shunting policy was adopted. The risk for the patients with contralateral carotid occlusion was not significantly higher than that for patients without occlusion. Results were not influenced by systematic/selective shunting policy, and the incidence of signs of cerebral ischemia was higher in patients with contralateral carotid occlusion.

Early carotid endarterectomy in selected stroke patients

Although there are several reports suggesting the safety of performing carotid endarterectomy (CE) within 4 weeks (early) of a nondisabling stroke, at many institutions it is not standard practice. Benefits of early surgery may include reduction in the number of strokes or carotid occlusions during the time between stroke and surgery, as well as a reduction in the cost of medical care due to the elimination of interval anticoagulation and close follow-up. This review examines the outcomes of early CE in selected patients after a nondisabling stroke. A total of 1065 CEs were performed between November 1991 and April 1998. Seventy-five patients were identified by computerized hospital record and office chart review as having CE after a nondisabling stroke. Criteria for early surgery included 1) nondisabling stroke ipsilateral to a carotid stenosis >50%, 2) neurological stability, and 3) no evidence of hemorrhagic stroke or significant cerebral edema by CT/MRI evaluation. This review suggests that early CE can be performed in selected patients with an acceptable perioperative morbidity and mortality.

Complications in carotid endarterectomy are predicted by qualifying symptoms and preoperative CT findings

OBJECTIVES

To relate the 30-day perioperative rate of stroke or death in carotid endarterectomy (CEA) to preoperative qualifying symptoms and to the presence of cerebral infarction (CI) demonstrated on computed tomography (CT).

DESIGN

Retrospective clinical study.

MATERIAL AND METHODS

Two hundred and seventy-two consecutive CEAs for symptomatic stenosis in 262 patients were analysed.

RESULTS

The total complication rate was 5.9%. Patients with retinal symptoms (n = 81) had no complications, TIA patients (n = 76) had 6.6% (p < 0.001). Patients qualifying with minor stroke (n = 113) had complications in 9.7% (N.S. compared to TIA patients). Patients qualifying with cortical symptoms had a significantly higher complication rate compared to those with retinal (8.4% vs. 0%, p = 0.004). The presence of a preoperative CT-verified infarction resulted in a higher risk for stroke or death (9.8% vs 2.8%, p = 0.008). Within the subgroup presenting with minor stroke, the presence of CI resulted in stroke or death in 13.9%. In patients without CI the corresponding figure was 2.4% (p = 0.017).

CONCLUSION

The qualifying symptoms and the presence of CI visualized by CT influence the complication rate in CEA. When evaluating risk and comparing outcome, these parameters should be included in reporting standards.

Anesthesia for carotid endarterectomy

Patients presenting for carotid endarterectomy provide anesthesiologists with many challenges. These include optimization of cerebrovascular hemodynamics and oxygen balance, as well as minimizing myocardial risk. Fiscal pressures have encouraged the development of clinical pathways in many centers, with a remarkable trend towards decreased intensive care unit utilization and length of hospital stay. Anesthetic and surgical practices vary widely, but outcomes in these high-risk patients are usually excellent despite these differences. The potential for expanded indications for carotid endarterectomy and development of percutaneous treatment for carotid stenosis will provide neurovascular anesthesiologists with additional incentives to refine the anesthetic management of these patients.