Carotid endarterectomy: does it work?

Characteristics of highly cited articles in cerebral angiography

OBJECTIVE

To present and analyze the characteristics of the 100 most cited articles that used cerebral angiography for clinical evaluation and intervention.

METHOD

Two researchers independently extracted articles from multiple databases and ranked them by citation count to create the "top 100 most-cited" list.

RESULTS

The top 100 articles received a total of 115,243 citations. Twenty-one of the top 100 articles were published between 2006 and 2010. Most studied disorder was ischemic stroke (n = 35), and cerebral angiography was used most frequently for diagnosis (n = 88).The United States was affiliated with the highest number of articles (n = 62), with Stroke publishing most articles (n = 22). Public sources funded 39 articles, private sources funded 35, and 38 articles reported conflicts of interest. Thirty-six studies were randomized controlled trials, and male authors held the majority of both first (n = 90) and senior (n = 88) authorship positions.

CONCLUSION

Within the scope of this study, the following features may define a typical highly cited article-a randomized controlled clinical trial conducted in the United States that studied ischemic stroke, used cerebral angiography for diagnosis, and was published relatively recently in a high-impact journal by male first and senior authors.

Evolution of Evidence-Based Medicine in Stroke

The introduction and evolution of evidence-based stroke medicine has realized major advances in our knowledge about stroke, methods of medical research, and patient outcomes that continue to complement traditional individual patient care. It is humbling to recall the state of knowledge and scientific endeavour of our forebears who were unaware of what we know now and yet pursued the highest standards for evaluating and delivering effective stroke care. The science of stroke medicine has evolved from pathophysiological theory to empirical testing. Progress has been steady, despite inevitable disappointments and cul-de-sacs, and has occasionally been punctuated by sensational breakthroughs, such as the advent of reperfusion therapies guided by imaging.

The Influence of Collagen Impregnation of a Knitted Dacron Patch Used in Carotid Endarterectomy

BACKGROUND

In selected populations, carotid endarterectomy (CEA) reduces long-term stroke risk. Studies have shown increased risk of restenosis with use of a collagen-impregnated Dacron patch compared to a polytetrafluorethylene patch. There is concern that collagen impregnation may initiate thrombosis or promote restenosis due to platelet activation. We performed a retrospective analysis of our CEA experience with routine patching using knitted Dacron patches with (Hemashield) and without (Sauvage) collagen impregnation.

METHODS

Our database was queried for all CEAs between January 2006 and December 2010. Seven surgeons performed 655 CEAs. Patients were excluded if no patch was used (n = 1), a primary CEA was performed before study period or by other surgeons (n = 11), or the patch type was indeterminable (n = 38). Demographics, clinical data, and outcomes were compared between the collagen-impregnated (C, Hemashield) group and non-collagen-impregnated (NC, Sauvage) group.

RESULTS

A total of 605 CEAs were analyzed (395 C and 210 NC). Demographics were similar except for coronary artery disease (C 54.3% vs. NC 41.6%, P = 0.003). There was no statistically significant difference in 30-day (C 99.7% vs. NC 99.5%, P > 0.99) or 5-year survival (C 80.0% vs. NC 83.7%, P = 0.26) or 30-day stroke rate (C 0.3% vs. NC 1.0%, P = 0.28). No late ipsilateral strokes occurred during 5-year follow-up. The 5-year freedom from restenosis >30% (C 85.3% vs. NC 86.4%, P = 0.33), restenosis >50% (C 94.5% vs. NC 95.5%, P = 0.44), and restenosis >70% (C 98.6% vs. NC 98.9%, P = 0.73) were similar. Two patients underwent carotid stenting for restenosis >70%. Two patients (both in the C group) developed occlusion of the carotid artery.

CONCLUSIONS

The thrombosis and restenosis rates in the 2 groups were similar. This suggests that collagen-impregnated patches do not initiate thrombosis or increase restenosis rates after CEA.

Vascular Surgery in Senescence Carotid Endarterectomy in Patients over 70 Years

In order to evaluate the immediate and long-term results of carotid endar terectomy in patients over seventy years of age, 54 patients undergoing a total of 59 surgical procedures were followed for a mean time of forty-three months. There was no operative mortality. Perioperative central neurological complica tions developed in 18 patients (33%), 9 (17%) of whom suffered permanent neurological deficits. During the follow-up period we found an annual stroke rate of 5% according to life table arialysis. The five-year survival rate was 67%. At termination of follow-up or before death, 85% of the patients lived indepen dently in their own homes. Compared with younger age groups, carotid endar terectomy in senescence yielded poorer results in terms of immediate and late neurological status. The old patients had, however, the same life expectancy as a contemporary age- and sex-matched population and had to a remarkable degree been able to maintain an independent life.

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 CEAresults.

Investigation:

Brain imaging with CTor 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 MRAor CTangiography, 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 ≥ 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.

Carotid artery stenting - current status of the procedure

Surgical carotid endarterectomy (CEA) was long considered the standard approach for the treatment of atherosclerotic carotid artery disease. This was based on results of several randomized trials demonstrating its effectiveness over the best medical therapy. In the past two decades, patients identified high-risk for surgery were offered carotid artery stenting (CAS) as a less invasive option. Despite its initial limitations, CAS has evolved into an elaborate method currently considered to be equivalent and in selected patients even preferable to CEA. However, outcomes of both procedures are highly operator dependent and a simple stratifying method to prioritize CAS, CEA or medical therapy only has not yet been proposed. In addition, recently published randomized trials highlighted the importance of proper patient selection and rigorous training contributing to low absolute rates of (procedural) adverse events. This review discusses the history and evidence for carotid revascularization and briefly presents technical aspects and innovations in CAS.

Chances and battles in stroke research

Here I have reviewed how good luck, bad luck and barriers determined my research directions in stroke over the last 30 or so years. Good luck should be exploited, and very often barriers can be not just overcome but put to good use as well. It is crucial for the young researcher to find mentors as good as I have had, and to move around to gain a broad experience, and for the experienced researchers to bring on the younger generation as I have tried to do.

Timing of clinically significant microembolism after carotid endarterectomy

PURPOSE

Post-operatively detected transcranial Doppler (TCD) embolic signals (ES) are associated with an increased risk of carotid endarterectomy (CEA) stroke/TIA. The aims here were to quantify this risk and determine the most efficient monitoring protocol.

METHODS

Sequential patients undergoing CEA (enrolled in a randomised, blinded, placebo-controlled trial of peri-operative dextran therapy) had 30-min TCD monitoring in the first post-operative hour. 30-min monitoring was also performed 2-3, 4-6 and 24-36 h post-operatively. First post-operative hour ES counts were correlated with peri-operative ipsilateral carotid stroke/TIA to determine the size of a clinically significant ES load and the magnitude of the associated risk. The exact Cochran-Armitage test for trend in proportions was used to determine when a clinically significant ES load was first detected.

RESULTS

141 patients (mean age 69.3 years, 72% male) were monitored during the first post-operative hour. An ES count >10 per recording was identified as the best overall predictor of ipsilateral stroke/TIA (sensitivity 72%, specificity 89%). 3/119 (2.5%) patients with 0-10 ES had ipsilateral carotid events compared to 8/22 (36.4%) patients with 11-115 ES (OR = 22.1, 95% CI 4.5, 138.4, p < 0.0001). 13/18 (72%) of subjects with >10 ES were identified in the first post-operative hour with no significant increase in the number of new cases over the subsequent 24-36 post-operative h (p = 0.354).

CONCLUSION

Patients with clinically significant post-operative microembolism had an approximately 15 times higher risk of ipsilateral stroke/TIA and most were identified during a 30-min study in the first post-operative hour.

Trends, complications, and mortality in peripheral vascular surgery

BACKGROUND

The recent evolution in treatments for peripheral vascular disease has dated available mortality statistics for vascular intervention. Moreover, many of our current mortality statistics are derived from single-institution studies that are often not reflective of outcomes in general practice. To provide current and generalizable data regarding mortality and trends for peripheral vascular interventions, we examined two national data sets (Nationwide Inpatient Sample, 1998-2003, and National Hospital Discharge Survey, 1979-2003) and four states (New York, California, Florida, and New Jersey, 1998-2003).

METHODS

Four procedures--abdominal aortic aneurysm repair (nonruptured), lower extremity revascularization, amputation, and carotid revascularization--were selected by cross-referencing International Classification of Diseases, 9th Revision, diagnostic and procedural codes. For significance, the t test was used for continuous variables, the chi2 test was used for dichotomous variables, and the chi2 test was used for mortality trends.

RESULTS

From 1998 to 2003, there was a progressive decrease in the national per capita rate of amputations: 13.2% overall and 21.2% for major amputations (P < .0001). Nationally and regionally, mortality has only slightly declined. For lower extremity revascularization, after a sharp increase during the 1980s to 100,000 open procedures, the volume remained constant for 10 years and began to decline in 1998, reaching 70,000 cases in 2003. In contrast, since 1996, endovascular interventions have increased 40%. Mortality during the 1998 to 2003 period remained virtually stable at 1.5% to 2% for endovascular procedures and 3% to 4% for open procedures. The overall volume of abdominal aortic aneurysm repair has not changed substantially for the past 6 years; however, endovascular repair is now used for nearly half the cases (46.5% regional and 43.0% national). Mortality for open repair has not changed, remaining at approximately 5%, whereas for endovascular repair, mortality has declined from 2.6% in 2000 to less than 1.5% in 2003. After the rapid increase in open carotid revascularization in the early 1990s, the total volume has declined 5% nationally from 1998 to 2003. Regional data demonstrated an overall 12% reduction in carotid revascularization volume since 1998; this reduction was due to a 16% decline in open carotid revascularization. During this same period, the use of angioplasty-stent carotid revascularization doubled. Mortality for the open procedures is 0.5% and is significantly higher (2%-3%) for endovascular carotid revascularization. Stroke rates for endovascular carotid revascularization are also higher: 2.13% vs 1.28% for open procedures (P < .0001).

CONCLUSIONS

Dramatic shifts in the management of peripheral vascular disease have occurred together with an overall decline in mortality. There seems to be a significant mortality advantage for endovascular as compared with traditional surgery except for carotid endarterectomy. The increasing safety of vascular interventions should be considered when deciding which patients to treat but with the caveat that endovascular interventions are not always safer than open repair.

Carotid artery surgery vs. stent: A cardiovascular perspective

Stroke is a major health catastrophe that is responsible for the third most common cause of death and the leading cause of disability. Carotid artery stenosis is an important cause of brain infarctions and the risk of stroke is directly related to the severity of carotid artery stenosis and to the presence of symptoms. Familiarity with different methods of measuring degrees of carotid artery stenosis is a key in understanding the role of revascularization of this disorder. Carotid endarterectomy (CEA), surgical removal of the carotid atherosclerotic plaque, is intended to prevent stroke in patients with carotid artery stenosis and currently the most commonly performed vascular procedure in the United States. Several randomized clinical trials had demonstrated the benefits of CEA in selected groups of patients with symptomatic and asymptomatic carotid artery stenosis. However, CEA can cause stroke, the very thing it intended to prevent, and is associated with significant perioperative complications such as those related to general anesthesia, cardiac or nerve injury. Moreover, several anatomical and medical conditions may limit candidates for CEA. Carotid artery stenting (CS) is an evolving and less invasive technique for carotid artery revascularization. Recent studies demonstrated that CS with embolic protection devices has become an alternative to CEA for high-surgical-risk patients and the procedure of choice for stenoses inaccessible by surgery. The role of CS in low risk patients awaits the completion of several ongoing studies.

Understanding trends in inpatient surgical volume: vascular interventions, 1980-2000

OBJECTIVE

To help understand past and future trends in vascular intervention, we examined changes in the rate of utilization, patient demographics, and length of stay from 1980 to 2000.

METHODS

We reviewed the ICD-9 codes for all vascular procedures using the National Hospital Discharge Survey of non-federal United States hospitals (1980-2000).

RESULTS

The number of vascular procedures performed in this country increased from 412,557 in 1980 to 801,537 in 2000 (per capita increase of >50%). This increase was most evident in elderly patients (>75 years, 67% per capita increase in discharges). Long hospital stays (> or =7 days) for vascular procedures fell 41%, and short hospital stays (<24 hours) increased 15% over the period of study. The frequency of abdominal aortic aneurysm repairs remained relatively constant. Except for an interval in the late 1980s, and a minor decrease from 1997 to 2000, the frequency of carotid endartarectomy rose dramatically (69%). Lower extremity revascularizations increased steadily until 1990 but then declined 12%. From 1995 to 2000, there was a 27% per capita decrease in the number of renal-mesenteric operations. Correspondingly, over the past 5 years there has been a 979% growth in the number of percutaneous/endovascular interventions. Despite a substantial number of interventions for lower extremity vascular disease, there was a concomitant increase in the number of major and minor amputations.

CONCLUSION

Interventions for vascular disease have increased dramatically, with a major shift toward less invasive treatments, particularly for the renal and mesenteric vessels and the lower extremities. These trends in procedural use suggest that vascular surgeons need to embrace catheter-based approaches if they want to remain leaders in the treatment of peripheral vascular diseases.

Variation and changes in state-specific carotid endarterectomy and 30-day mortality rates, United States, 1991-2000

OBJECTIVES

The objectives of this study were to investigate variations between states and changes in state-specific carotid endarterectomy (CEA) and 30-day mortality rates. Cross-sectional variations and changes over time in such measures may be indicative of improvement in the quality of care.

METHODS

We performed retrospective analyses of pre-existing administrative data on Medicare beneficiaries aged 65 years and older in the United States. Age-adjusted, state-specific CEA rates and 30-day postoperative mortality rates in 1991, 1995 and 2000 were examined, as well as changes in these rates from 1991 to 1995 and from 1995 to 2000. Stroke mortality in the general population of each state was used as a crude measure of the need for CEA procedure in the state. The Spearman rank correlation analysis was used to study correlations between rates. Oldham's method was used to avoid the effect of regression to the mean.

RESULTS

There were wide variations in the state-specific CEA rates, 30-day mortality, and in changes in these rates over time. The states with relatively low procedure rates in 1991 also had low rates in 1995 and 2000, and relatively higher increases in the rates. The states with relatively high 30-day mortality in 1991 or 1995 had lower increases or greater decreases in the rate. CEA rates were not correlated with any measure of surgical mortality, but they were correlated with stroke mortality in the general population.

CONCLUSIONS

The inter-state variation in CEA rates has not changed much since 1991, but variation in 30-day mortality decreased through 2000. The states with low procedure rates in 1991 did not have sufficient increase to catch up with the high-rate states by 1995, but they were prone to experience a higher increase in the subsequent 5 years. The validity of stroke mortality in a state as a measure of the need for CEA is questionable. Further research using clinical data is needed to better explain variations between states.

Overview of the principal results and secondary analyses from the European and North American randomised trials of endarterectomy for symptomatic carotid stenosis

OBJECTIVES

Review of the primary results and secondary analyses from the European Carotid Surgery Trial (ECST) and the North American Symptomatic Carotid Endarterectomy Trial (NASCET).

DESIGN

Review of 48 ECST and NASCET papers.

RESULTS

The simple assumption that all patients with a symptomatic stenosis >70% benefit from CEA is untenable. Approximately 70-75% will not have a stroke if treated medically. The ECST and NASCET have identified subgroups that should have expedited investigation and surgery (male sex, age >75 years, 90-99% stenosis, irregular plaque, hemispheric symptoms, recurrent events for >6 months, contralateral occlusion, multiple co-morbidity). Accordingly development of local protocols for patient selection/exclusion should involve surgeons and physicians and take account of the local operative risk. The ECST and NASCET have also shown that the ubiquitous "string sign" is not associated with a high risk of stroke, and emergency CEA is unnecessary.

CONCLUSIONS

Surgeons must quote their own results and be aware that a high operative risk reduces long-term benefit. Accordingly, in those centres with a higher operative death/stroke rate, some "lower risk" patients should probably be considered for best medical therapy alone. It is hoped that pooling of the ECST and NASCET databases will enable more definitive guidelines to be developed regarding who benefits most from CEA.

Surgical quality assurance in the Ischemic Optic Neuropathy Decompression Trial (IONDT)

The purpose of this article is to report the methods and results of the surgical quality assurance program associated with the Ischemic Optic Neuropathy Decompression Trial (IONDT). A surgical quality assurance committee developed and implemented a quality assurance program for a randomized clinical trial requiring surgical intervention. A surgical technique questionnaire was administered at two times during the study course, and maintenance of surgeon certification required submission and approval of a masked videotape of an optic nerve sheath decompression surgery by each study surgeon. Surgical quality was assessed through completion of surgical report forms and standardized, masked review of operative notes. Rates of compliance and intra- and interreviewer agreement were assessed for each aspect of the program. Twenty-five of 32 surgeons (81%) successfully completed and maintained certification. Item agreement varied from 21-92% among reviewers of satisfactory videotapes and 22-89% on unsatisfactory videotapes. Intrarater agreement for videotape acceptability was 11 of 13 (85%), and for specific surgical steps, 147 of 182 (81%). Operative notes were submitted for 123 of 125 (98%) patients receiving surgery. Interrater agreement on individual items ranged from 73-100%. Classification of individual items was identical on first and second review for 1285 of 1344 (95.6%) items. Overall agreement for individual reviewers was 93.8-97.8%. We conclude that use of a small peer review committee, which developed and oversaw a quality assurance program, allowed for consistent certification and monitoring of surgical performance. This in turn increased the credibility of the IONDT results, which demonstrated no difference in outcome between operated and unoperated groups of patients.

Noninvasive analysis of conjunctival microcirculation during carotid artery surgery reveals microvascular evidence of collateral compensation and stenosis-dependent adaptation

OBJECTIVE

Hemodynamically relevant internal carotid artery (ICA) stenosis is a major cause of ischemic stroke. Despite its long-term benefit, carotid endarterectomy may also be associated with severe neurologic deficits. Intraoperative and early recognition of ischemia in the region of the ICA may reduce this risk. To date, direct imaging and quantitative analysis of microvascular structures and function in the human ICA region have not been possible. We purposed to visualize and quantify ischemia/reperfusion-induced microcirculatory changes in the terminal vascular bed of the ICA in patients undergoing unilateral ICA endarterectomy.

METHODS

Sequential analysis of the ipsilateral and contralateral conjunctival microcirculation was performed with orthogonal polarized spectral imaging in 33 patients undergoing unilateral ICA endarterectomy because of moderate or severe ICA stenosis (North American Symptomatic Carotid Endarterectomy Trial score, 75% +/- 13%), before clamping the ICA (baseline), during clamping of the external carotid artery and ICA, during reperfusion of the ICA (intraluminal shunt), during the second clamping of the ICA (shunt removal), after declamping (reperfusion) of the external carotid artery and ICA, and 15 to 20 minutes after the second ICA reperfusion.

RESULTS

During ICA clamping for shunt placement, ipsilateral and contralateral conjunctival capillary perfusion was significantly decreased, but it was completely restored after reperfusion with carotid shunting. Reclamping of the ICA for shunt removal caused microvascular dysfunction, which was significantly less pronounced than that observed during the first clamping. The individual degree of ICA stenosis was inversely correlated with the ipsilateral and contralateral decrease in conjunctival functional capillary density during the first ICA clamping.

CONCLUSIONS

These results suggest adaptive mechanisms of capillary perfusion with increasing stenosis and development of collateral compensatory circulation in the vascular region of the human ICA. Conjunctival orthogonal polarized spectral imaging during unilateral ICA reconstruction enables continuous noninvasive analysis of bilateral conjunctival microcirculation in the terminal region of the ICA and enables monitoring for efficient carotid shunt perfusion during and after endarterectomy.

Association of sex with perioperative mortality and morbidity after carotid endarterectomy for asymptomatic carotid stenosis

OBJECTIVE

To examine whether perioperative morbidity and mortality after carotid endarterectomy depend on the sex and the presence of symptoms on presentation.

DESIGN

Retrospective review of quality assurance database prospectively collected.

SETTING

A university teaching hospital.

PARTICIPANTS

One thousand two hundred eighty-seven patients who had 1,503 carotid endarterectomies from 1990 to 1999 from a quality assurance database.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The cases were divided into 4 groups by sex and symptoms on presentation: male-symptomatic (MS), male-asymptomatic (MA), female-symptomatic (FS), and female-asymptomatic (FA). The 4 groups were compared for preoperative demographic and comorbidity profiles, carotid plaque characteristics, and outcome. Outcome measures included in-hospital stroke, myocardial infarction (MI), congestive heart failure (CHF), and death. There were 496 cases in the MS group, 407 in the MA group, 315 in the FS group, and 285 in the FA group. Women were less likely to have a history of coronary artery disease, prior MI, or smoking, and their carotid plaques were less likely to be ulcerated or contain intraplaque hemorrhage. Even when controlling for the comorbidities and plaque characteristics, the incidence of each of the complications examined was low and not significantly different between the sexes in both the symptomatic and asymptomatic groups. The rate of stroke or death was 3.0% (MS) versus 1.9% (FS) (p = NS) and 1.2% (MA) versus 1.8% (FA) (p = NS).

CONCLUSION

There is no significant sex difference in perioperative cardiac or cerebrovascular complications. Women with symptomatic or asymptomatic carotid stenosis can have acceptably low complication rates from carotid endarterectomy and may benefit from the surgery as much as men.

Auditing carotid endarterectomy: a regional experience

BACKGROUND

Proof from randomized controlled trials that carotid endarterectomy (CEA) is efficacious in stroke prevention has resulted in a large resurgence of its use in recent years. We wished to determine if patients in our region were being selected and treated with complication rates consistent with the randomized trials.

METHODS

We have completed four audits of CEAs performed in our region since 1994, each followed by feed-back of results to the participating surgeons. Operations for > 70% symptomatic stenosis were considered appropriate, those for 50%-69% symptomatic and > 60% asymptomatic stenosis were considered uncertain and all others, including those in medically or neurologically unstable patients, were designated inappropriate. In part 4, the referral source and nature of the patients was also determined.

RESULTS

Part 1 (April 1994-September 1995) found that of 291 CEAs performed 33% were appropriate, 48% were uncertain and 18% were inappropriate, and 40% of patients who underwent CEA were asymptomatic. In part 2 (September 1996-September 1997) appropriate indications significantly improved to 49% of 184 CEAs (P=0.005), uncertain indications remained nearly the same at 47%, inappropriate indications fell to 4% (P=.00002), and asymptomatic patients remained at 40%. The results of part 3 (October 1997-October 1998) remained nearly the same as part 2 (249 CEAs, 47% appropriate, 51% uncertain, 2% inappropriate, 45% asymptomatic). Part 4 (October 1999-October 2000) results were significantly better than part 3, appropriate indications increasing from 47% to 58% of 222 CEAs (P=0.02), and an elimination of inappropriate operations (P=0.03). Stroke and death complications declined over the study period from an overall rate of 5.2% in part 1 to 2.3% in part 4. In part 4 the majority of patients (69%) were referred to surgeons directly from general practitioners, including 58 (73%) of the 80 asymptomatic patients who underwent CEA.

INTERPRETATION

Regular auditing and feedback of results and information to surgeons has resulted in significant and continued improvements in the surgical performance of CEA in our region. Since the majority of patients are referred directly to surgeons by general practitioners, it is important that this group of physicians be familiar with current CEA guidelines.

Carotid artery stent placement for atherosclerotic disease: rationale, technique, and current status

Carotid arterial endarterectomy is considered to be the standard for the treatment of atherosclerotic carotid arterial occlusive disease. This has been validated with results of several randomized controlled trials in which its effectiveness has been demonstrated over that of the best nonsurgical therapy. In the past several years, however, carotid angioplasty with stent placement has emerged as a potential alternative to carotid endarterectomy. This article represents a critical examination of the rationale for carotid revascularization; the history of endovascular techniques for the treatment of carotid atherosclerosis, beginning with balloon angioplasty and evolving to the use of stents; and the evidence supporting the effectiveness of the endovascular approach. A brief description of the current technical aspects of carotid artery stent placement is presented. The future status of the endovascular approach will be determined with randomized trials in which carotid artery stent placement is directly compared with endarterectomy, as well as by the potential for further innovation and improvement in endovascular devices, technique, and safety.

Carotid Endarterectomy: Surgical Techniques, Emboli, and Outcomes

Carotid endarterectomy (CEA) is now the single most commonly performed peripheral vascular procedure in the western world, and is one of the few surgical procedures to be evaluated in level 1 randomized trials. Yet, despite that it has a proven role in selected patients it still remains a source of continuing debate. At pres ent, there is little consensus on many of the individual aspects of the procedure, such as the role of patching, shunting, and general anesthesia. More recently, there has been an increasing interest in the role of periopera tive monitoring, largely because of increasing aware ness that most strokes follow inadvertent surgeon error. This article reviews the surgical aspects of CEA together with an overview of the evolution of a monitor ing program, which has contributed to a 60% reduction in operative risk.

Stroke prevention: cardiac and carotid-related stroke

The aim of this article is to discuss cardiac sources of stroke as well as the management of symptomatic and asymptomatic carotid stenosis. The authors detail the risks of cardioembolic stroke in the following conditions: aortic arch atheroma, atrial fibrillation, atrial myxoma, atrial septal aneurysm, dilated cardiomyopathy, infective endocarditis, left ventricular thrombus, mitral annular calcification, mitral valve prolapse, patent foramen ovale, prosthetic heart valves, valvular strands, and the optimal medical management for these conditions. The indications for carotid endarterectomy, angioplasty, and stenting are also outlined.

The fall and rise of carotid endarterectomy in the United States and Canada

BACKGROUND

Randomized clinical trials have demonstrated the efficacy of carotid endarterectomy in the prevention of stroke when the procedure is performed in regional centers of surgical excellence. However, the relative effects of these studies on the rates of carotid endarterectomy in the United States and Canada have been unclear.

METHODS

We calculated the annual rate of carotid endarterectomy in the U.S. states of California and New York and in the Canadian province of Ontario from 1983 through 1995. We also studied whether patients in the early 1990s were selectively referred to hospitals with high volumes of procedures and historically low in-hospital mortality rates.

RESULTS

Rates of carotid endarterectomy fell in all three regions from 1984 to 1989 (from 126 to 66 per 100,000 adults 40 years of age or older in California, from 65 to 40 per 100,000 in New York, and from 40 to 15 per 100,000 in Ontario), after the publication of studies demonstrating that the rates of complications of carotid endarterectomy were unacceptably high. However, the clinical trials of the 1990s, which showed benefit from carotid endarterectomy, were associated with a dramatic resurgence in the rates of the procedure from 1989 to 1995 (from 66 to 99 per 100,000 in California, from 40 to 96 per 100,000 in New York, and from 15 to 38 per 100,000 in Ontario). These increased rates were not associated with proportionally greater numbers of referrals of patients to hospitals with low mortality rates.

CONCLUSIONS

There have been a dramatic fall and rise in the rates of carotid endarterectomy in both the United States and Canada, which correlate with the publication of first unfavorable and then favorable clinical studies. The absence of selective referral of patients to centers with the lowest mortality rates raises questions about whether the benefits of carotid endarterectomy in the general population are similar to those demonstrated in the clinical trials.

Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators

BACKGROUND

Previous studies have shown that carotid endarterectomy in patients with symptomatic severe carotid stenosis (defined as stenosis of 70 to 99 percent of the luminal diameter) is beneficial up to two years after the procedure. In this clinical trial, we assessed the benefit of carotid endarterectomy in patients with symptomatic moderate stenosis, defined as stenosis of less than 70 percent. We also studied the durability of the benefit of endarterectomy in patients with severe stenosis over eight years of follow-up.

METHODS

Patients who had moderate carotid stenosis and transient ischemic attacks or nondisabling strokes on the same side as the stenosis (ipsilateral) within 180 days before study entry were stratified according to the degree of stenosis (50 to 69 percent or <50 percent) and randomly assigned either to undergo carotid endarterectomy (1108 patients) or to receive medical care alone (1118 patients). The average follow-up was five years, and complete data on outcome events were available for 99.7 percent of the patients. The primary outcome event was any fatal or nonfatal stroke ipsilateral to the stenosis for which the patient underwent randomization.

RESULTS

Among patients with stenosis of 50 to 69 percent, the five-year rate of any ipsilateral stroke (failure rate) was 15.7 percent among patients treated surgically and 22.2 percent among those treated medically (P=0.045); to prevent one ipsilateral stroke during the five-year period, 15 patients would have to be treated with carotid endarterectomy. Among patients with less than 50 percent stenosis, the failure rate was not significantly lower in the group treated with endarterectomy (14.9 percent) than in the medically treated group (18.7 percent, P=0.16). Among the patients with severe stenosis who underwent endarterectomy, the 30-day rate of death or disabling ipsilateral stroke persisting at 90 days was 2.1 percent; this rate increased to only 6.7 percent at 8 years. Benefit was greatest among men, patients with recent stroke as the qualifying event, and patients with hemispheric symptoms.

CONCLUSIONS

Endarterectomy in patients with symptomatic moderate carotid stenosis of 50 to 69 percent yielded only a moderate reduction in the risk of stroke. Decisions about treatment for patients in this category must take into account recognized risk factors, and exceptional surgical skill is obligatory if carotid endarterectomy is to be performed. Patients with stenosis of less than 50 percent did not benefit from surgery. Patients with severe stenosis (> or =70 percent) had a durable benefit from endarterectomy at eight years of follow-up.

Evaluation of cerebral function after carotid endarterectomy

Neuroimaging methods have failed to disclose correlation between degree of cerebral atrophy and blood flow in carotid artery stenosis patients. Moreover, intellectual improvement after carotid endarterectomy does not correlate fully with neuroimaging data in such patients. We performed brain electrical activity mapping and psychological testing before and 4 weeks after operation in 28 patients with symptomatic, high-grade, carotid stenosis. Postoperatively, electroencephalographic (EEG) mean frequency and absolute theta power improved significantly (p < 0.01). Mean frequency increased >1 Hz in most areas while power decreased dramatically, mainly because of resolution of high-voltage foci in 8 patients. Differences were conspicuous in both frontal lobes irrespective of the operated side, which suggests changes in perfusion affecting the whole brain. This is a positive effect of endarterectomy. Mini-Mental test and Set Test for verbal fluency had a positive correlation with the qEEG changes. Quantitative EEG as a measure of cerebral function has disclosed discriminative improvement in the early postoperative period. Our results support the thesis of improvement subsequent to endarterectomy.

Does the choice of material influence early morbidity in patients undergoing carotid patch angioplasty?

BACKGROUND

This study was undertaken to determine whether the choice of material influences the early morbidity of patients undergoing carotid patch angioplasty.

METHODS

Before undergoing carotid endarterectomy, 190 patients were randomized to receive 207 patch closures with either Dacron (USCI Sauvage knitted velour) or saphenous vein harvested from the thigh.

RESULTS

One hundred seven Dacron and 100 vein patch angioplasties were performed. No significant difference was seen between the two groups in patient age, sex preoperative risk factors, or indication for operation (p > 0.25 for each variable). Among the patients undergoing Dacron patch angioplasty three strokes (two temporary and one permanent), seven episodes of bleeding requiring reoperation, and two neck wound infections requiring rehospitalization occurred. The final 32 patients with Dacron patch closures had their anticoagulation reversed and had no bleeding complications. Complications inpatients undergoing vein patch closure included one fatal perioperative stroke, two episodes of bleeding requiring reoperation including one patch rupture, and three groin infections requiring hospitalization. No significant difference was seen between the two groups in the rate of perioperative stroke (p = 0.62), episodes of bleeding (p = 0.17), or infection (p = >0.67).

CONCLUSIONS

Carotid patch angioplasty can be performed with an acceptably low complication rate with either Dacron or vein, and the choice of patch material does not clinically affect patient morbidity. However, reversal of anticoagulation is recommended to minimize bleeding complications in patients undergoing Dacron patch angioplasty.

Carotid endarterectomy in Great Britain and Ireland: practice between 1984 and 1992

Of 356 questionnaires on carotid endarterectomy sent to all vascular surgeons in Great Britain and Ireland likely to undertake this procedure, 326 (92 per cent) were returned. Of those who replied 131 (40 per cent) performed at least one carotid endarterectomy in 1992; 57 (44 per cent) of these carried out ten or fewer operations and 74 (56 per cent) more than ten. The 131 surgeons were collectively responsible for 2628 operations in 1992, twice as many as were undertaken in either 1984 or 1989, years for which similar survey data are available. This sharp rise in the number of operations was accounted for by increased activity on the part of experienced operators, rather than any rise in the number of 'occasional' carotid surgeons. In 1992, although the neurologist remained a major source of patient referral, general practitioners (and others) were also referring patients in large numbers direct to the vascular surgeon; this represents a change in practice compared with previous years. Many of the technical aspects surrounding carotid endarterectomy remained unchanged over the years surveyed (1984, 1989, 1992) but by 1992 duplex scanning, intra-arterial (but not intravenous) digital subtraction angiography and transcranial Doppler ultrasonography had become established as clinically useful techniques.

Carotid endarterectomy for unstable and compelling neurologic conditions: do results justify an aggressive approach?

PURPOSE

In a retrospective study the outcome of 70 carotid endarterectomies (CEA) in 68 patients with neurologically unstable conditions or anatomically compelling findings on carotid angiography was examined to more accurately identify patients who might benefit from CEA in this setting.

METHODS

Out of a total of 1734 CEAs performed from 1978 to 1992, five groups of patients were selected: group A, stroke in evolution with tight stenosis (n = 5); group C, crescendo transient ischemic attacks (CTIA) continuing despite heparin (n = 14); group D, CTIA (above criteria) ceasing with heparin (n = 21); and group E, anatomically compelling situation on carotid angiography (n = 13). Data collected included preoperative and postoperative Neurologic Event Severity Score (NESS), CHAT classification, arteriosclerosis risk factors, demographics, and long-term overall and transient ischemic attack/stroke-free survival rates.

RESULTS

Risk factors and demographics were similar in all groups. By NESS criteria the conditions of 97.3% of patients in the neurologically unstable groups A to C were improved or stabilized after operation, with one deterioration (2.7%). All patients in group B either stabilized or improved. In group D, one patient's NESS deteriorated, resulting in 3.5% overall morbidity rate and no deaths for groups A to D. Follow-up showed an overall survival rate by Kaplan-Meier analysis equivalent to a matched control population, with 85% alive at 5 years. The cumulative TIA/stroke-free survival rate at 5 years was 75%.

CONCLUSIONS

In this retrospective series, CEA performed for compelling or unstable neurologic findings carried low morbidity and mortality rates. Early aggressive surgical therapy of neurologically unstable patients may be warranted because our results improved on the anticipated natural history of the conditions studied. Further clarification of proper patient selection is necessary before this principle can be applied broadly.

The geriatric "medical and public health" imperative revisited

Attempts to reduce the future demand for institutional care through community services are likely to have limited success. For this reason, health professionals must focus on preventing or ameliorating functional decline in older persons. To focus attention on this aspect of the geriatric imperative, we use an epidemiologic model to estimate the potential impact of existing or potential medical and public health interventions that might decrease the incidence of functional decline. For at least three major causes (stroke, hip fracture, and incontinence) of disability, the potential exists for reducing the incidence and burden of functional disability by a number of mechanisms. For example, treating just half of adults age 65-74 with currently untreated diastolic or isolated systolic hypertension would reduce the incidence of stroke by 2.77% in this age group (or 1,500 fewer cases of stroke annually). The estimates presented indicate the need (1) to better implement those interventions that are known to be efficacious, and (2) to identify and to test new interventions for conditions contributing to functional impairment in the elderly.

Prevention of ischemic stroke: the role of carotid endarterectomy in symptomatic patients

Carotid endarterectomy (CE) has recently been proved to be beneficial in symptomatic patients with severe (70-99%) appropriate carotid stenosis. After discussing the historical evolution of CE as a possible preventive treatment of ischemic stroke, we review the results of North American and European trials in order to give practical information for the management of cerebrovascular patients.

Comparison of multicenter study designs for investigation of carotid endarterectomy efficacy

BACKGROUND

Our report summarizes and compares the characteristics of six prospective, multicenter, randomized clinical trials of carotid endarterectomy underway in North America and Europe.

SUMMARY OF REVIEW

Three trials are designed to evaluate the safety and efficacy of endarterectomy in patients with asymptomatic carotid artery stenosis. The other three trials enroll patients who have had transient ischemic attacks or a minor cerebral infarction in the distribution of the randomized artery. Considered together, these six clinical trials span the range of candidates for carotid endarterectomy. The inclusion and exclusion criteria, methodology, and statistical considerations of each study are detailed in tables.

CONCLUSIONS

The results from these trials will be helpful in resolving some of the questions surrounding endarterectomy, provided the similarities and differences in the study designs are considered when interpreting the results.

Progression to total occlusion is an underrecognized complication of the medical management of carotid disease

One potential complication of carotid disease is progression to total occlusion while under medical management. To investigate this important issue, 44 patients (31 men; 13 women) ranging in age from 44 to 83 (mean, 65.9) years with internal carotid artery occlusions as a result of arteriosclerosis were identified among 993 patients undergoing carotid angiography from Jan. 1, 1985 to Dec. 31, 1989, and their prior medical records were reviewed. Clinical presentations included stroke in 9 (20.5%), retinal infarct in 8 (18.2%), transient ischemic attacks in 10 (22.7%), amaurosis fugax in 4 (9.1%), nonhemispheric symptoms in 3 (6.8%), and 10 (22.7%) were asymptomatic. A review of these patients' medical records documented that prior hemispheric symptoms referrable to the now occluded internal carotid artery had occurred in five (55%) of the nine patients who were admitted with stroke, five (62%) of the eight patients with a retinal infarct, six (60%) of the 10 patients who were admitted with a transient ischemic attack, all four (100%) patients who were admitted with amaurosis fugax, one (33%) of three patients with nonhemispheric symptoms, and in seven (70%) of the 10 patients who were asymptomatic when the internal carotid artery occlusion was identified angiographically. In summary, 28 (64%) of the 44 patients had experienced ipsilateral symptoms from 2 to 120 (mean, 30) months before the diagnosis of internal carotid artery occlusion; only eight (28%) had undergone noninvasive or angiographic evaluation, and all were placed on antiplatelet therapy when prior hemispheric symptoms developed.(ABSTRACT TRUNCATED AT 250 WORDS)