The value of carotid endarterectomy in reducing the morbidity and mortality of recurrent stroke

Screening for Significant Carotid Artery Disease among a Cohort of 1,000 Egyptian Patients

The objective of this study was to determine the prevalence of significant carotid artery disease (SCAD) in a cohort of Egyptian patients to compare it with matched groups of patients in published data of Western populations. One thousand consecutive patients referred for color flow duplex scanning of the carotid arteries were included. SCAD was defined as carotid stenosis ≥ 50% or occlusion. There were 567 males (56.7%), and the mean age was 60.4 years. There were 382 (38.2%) patients presenting with and 617 (61.7%) patients without specific carotid territory symptoms. SCAD was significantly more prevalent in patients aged ≥ 60 (13.2%, vs 6.25%; p < .001), in symptomatic patients (16.45% vs 6.32%; p < .001), in diabetics (15.96% vs 7.39%; p < .001), in patients with ischemic heart disease (17.65% vs 7.22%; p < .001), in hypertensive patients (12% vs 7.54%; p = .025), and in patients with dyslipidemia (12.53% vs 6.56%; p < .025). The prevalence of SCAD in this cohort of Egyptian patients was similar to that of matched patients of Western populations. Screening for SCAD in patients with specific carotid territory symptoms is recommended. Screening of asymptomatic subjects could be considered if they are ≥ 60 years of age and have three or more associated risk factors.

Protection by a manganese porphyrin of endogenous peroxynitrite-induced death of glial cells via inhibition of mitochondrial transmembrane potential decrease

In the cerebral ischemic penumbra, progressive metabolic deterioration eventually leads to death of glial cells. The exact mechanism for the death of glial cells is unclear. Here we report that under glucose-deprived conditions immunostimulated glial cells rapidly underwent death via production of large amounts of peroxynitrite. The cell-permeable Mn(III)tetrakis(N-methyl-4'-pyridyl)porphyrin (MnTMPyP) caused a concentration-dependent attenuation of the increased death in glucose-deprived immunostimulated glial cells. The structurally related compound H(2)TMPyP, which lacks metals, did not attenuate this augmented cell death. MnTMPyP prevented the elevation in nitrotyrosine immunoreactivity (a marker of ONOO(-)) in glucose-deprived immunostimulated glial cells. In glucose-deprived glial cells, MnTMPyP also completely blocked the augmented death and nitrotyrosine immunoreactivity induced by the ONOO(-)-producing reagent 3-morpholinosydnonimine (SIN-1). The mitochondrial transmembrane potential (MTP), as measured using the dye JC-1, was rapidly decreased in immunostimulated or SIN-1-treated glial cells deprived of glucose. MnTMPyP, but not H(2)TMPyP, blocked the depolarization of MTP in those glial cells. The present data, at least in part, provide evidence for how glial cells die in the postischemic and/or recurrent ischemic brain.

Immunostimulated glial cells potentiate glucose deprivation-induced death of cultured rat cerebellar granule cells

The present study investigates whether immunostimulated glial expression of inducible nitric oxide synthase influences the glucose deprivation-induced death of rat cerebellar granule cells (CGC). CGC/glia cocultures were immunostimulated by interferon-gamma (200 U/ml) and lipopolysaccharides (1 microg/ml) and 2 days later were challenged by glucose deprivation. Neurotoxicity was assessed by measuring the release of lactate dehydrogenase. Neither a 2-h glucose deprivation nor a 2-day immunostimulation altered the viability of CGC. A 2-day immunostimulation, however, markedly potentiated the glucose deprivation-induced death of CGC. The increased death of glucose-deprived CGC after immunostimulation was mimicked by the nitric oxide (NO) releasing reagent 3-morpholinosydnonimine (SIN-1) and was partially prevented by the NO synthase (NOS) inhibitor N(G)-nitroarginine. The increased death of glucose-deprived CGC either after immunostimulation or by SIN-1 was not altered by various N-methyl-D-aspartate (NMDA) and non-NMDA receptor antagonists. Because superoxide dismutase and catalase, which remove superoxide anion, decreased the augmented death of glucose-deprived immunostimulated CGC, the reaction of NO with superoxide to form peroxynitrite appears to be implicated in the potentiated neurotoxicity. Our data indicate that immunostimulated glial cells potentiate the death of glucose-deprived neurons in part through the expression of inducible NOS but not through NMDA receptor activation. Potentiation of glucose-deprived CGC death by immunostimulated glial cells may be clinically implicated in the tendency of recurrent ischemic insults to be more severe and fatal than an initial ischemic insult.

Guidelines for carotid endarterectomy. A multidisciplinary consensus statement from the Ad Hoc Committee, American Heart Association

BACKGROUND AND PURPOSE

Indications for carotid endarterectomy have engendered considerable debate among experts and have resulted in publication of retrospective reviews, natural history studies, audits of community practice, position papers, expert opinion statements, and finally prospective randomized trials. The American Heart Association assembled a group of experts in a multidisciplinary consensus conference to develop this statement.

METHODS

A conference was held July 16-18, 1993, in Park City, Utah, that included recognized experts in neurology, neurosurgery, vascular surgery, and healthcare planning. A program of critical topics was developed, and each expert presented a talk and provided the chairman with a summary statement. From these summary statements a document was developed and edited onsite to achieve consensus before final revision.

RESULTS

The first section of this document reviews the natural history, methods of patient evaluation, options for medical management, results of surgical management, data from position statements, and results to date of prospective randomized trials for symptomatic and asymptomatic patients with carotid artery disease. The second section divides 96 potential indications for carotid endarterectomy, based on surgical risk, into four categories: (1) Proven: This is the strongest indication for carotid endarterectomy; data are supported by results of prospective contemporary randomized trials. (2) Acceptable but not proven: a good indication for operation; supported by promising but not scientifically certain data. (3) Uncertain: Data are insufficient to define the risk/benefit ratio. (4) Proven inappropriate: Current data are adequate to show that the risk of surgery outweighs any benefit.

CONCLUSIONS

Indications for carotid endarterectomy in symptomatic good-risk patients with a surgeon whose surgical morbidity and mortality rate is less than 6% are as follows. (1) Proven: one or more TIAs in the past 6 months and carotid stenosis > or = 70% or mild stroke within 6 months and a carotid stenosis > or = 70%; (2) acceptable but not proven: TIAs within the past 6 months and a stenosis 50% to 69%, progressive stroke and a stenosis > or = 70%, mild or moderate stroke in the past 6 months and a stenosis 50% to 69%, or carotid endarterectomy ipsilateral to TIAs and a stenosis > or = 70% combined with required coronary artery bypass grafting; (3) uncertain: TIAs with a stenosis < 50%, mild stroke and stenosis < 50%, TIAs with a stenosis < 70% combined with coronary artery bypass grafting, or symptomatic, acute carotid thrombosis; (4) proven inappropriate: moderate stroke with stenosis < 50%, not on aspirin; single TIA, < 50% stenosis, not on aspirin; high-risk patient with multiple TIAs, not on aspirin, stenosis < 50%; high-risk patient, mild or moderate stroke, stenosis < 50%, not on aspirin; global ischemic symptoms with stenosis < 50%; acute dissection, asymptomatic on heparin. Indications for carotid endarterectomy in asymptomatic good-risk patients performed by a surgeon whose surgical morbidity and mortality rate is less than 3% are as follows. (1) Proven: none. As this statement went to press, the National Institute of Neurological Disorders and Stroke issued a clinical advisory stating that the Institute has halted the Asymptomatic Carotid Atherosclerosis Study (ACAS) because of a clear benefit in favor of surgery for patients with carotid stenosis > or = 60% as measured by diameter reduction. When the ACAS report is published, this indication will be recategorized as proven. (2) acceptable but not proven: stenosis > 75% by linear diameter; (3) uncertain: stenosis > 75% in a high-risk patient/surgeon (surgical morbidity and mortality rate > 3%), combined carotid/coronary operations, or ulcerative lesions without hemodynamically significant stenosis; (4) proven inappropriate: operations with a combined stroke morbidity and mortality > 5%.

Guidelines for carotid endarterectomy. A multidisciplinary consensus statement from the ad hoc Committee, American Heart Association

BACKGROUND AND PURPOSE

Indications for carotid endarterectomy have engendered considerable debate among experts and have resulted in publication of retrospective reviews, natural history studies, audits of community practice, position papers, expert opinion statements, and finally prospective randomized trials. The American Heart Association assembled a group of experts in a multidisciplinary consensus conference to develop this statement.

METHODS

A conference was held July 16-18, 1993, in Park City, Utah, that included recognized experts in neurology, neurosurgery, vascular surgery, and healthcare planning. A program of critical topics was developed, and each expert presented a talk and provided the chairman with a summary statement. From these summary statements a document was developed and edited onsite to achieve consensus before final revision.

RESULTS

The first section of this document reviews the natural history, methods of patient evaluation, options for medical management, results of surgical management, data from position statements, and results to date of prospective randomized trials for symptomatic and asymptomatic patients with carotid artery disease. The second section divides 96 potential indications for carotid endarterectomy, based on surgical risk, into four categories: (1) Proven: This is the strongest indication for carotid endarterectomy; data are supported by results of prospective contemporary randomized trials. (2) Acceptable but not proven: a good indication for operation; supported by promising but not scientifically certain data. (3) Uncertain: Data are insufficient to define the risk/benefit ratio. (4) Proven inappropriate: Current data are adequate to show that the risk of surgery outweighs any benefit.

CONCLUSIONS

Indications for carotid endarterectomy in symptomatic good-risk patients with a surgeon whose surgical morbidity and mortality rate is less than 6% are as follows. (1) Proven: one or more TIAs in the past 6 months and carotid stenosis > or = 70% or mild stroke within 6 months and a carotid stenosis > or = 70%; (2) acceptable but not proven: TIAs within the past 6 months and a stenosis 50% to 69%, progressive stroke and a stenosis > or = 70%, mild or moderate stroke in the past 6 months and a stenosis 50% to 69%, or carotid endarterectomy ipsilateral to TIAs and a stenosis > or = 70% combined with required coronary artery bypass grafting; (3) uncertain: TIAs with a stenosis < 50%, mild stroke and stenosis < 50%, TIAs with a stenosis < 70% combined with coronary artery bypass grafting, or symptomatic, acute carotid thrombosis; (4) proven inappropriate: moderate stroke with stenosis < 50%, not on aspirin; single TIA, < 50% stenosis, not on aspirin; high-risk patient with multiple TIAs, not on aspirin, stenosis < 50%; high-risk patient, mild or moderate stroke, stenosis < 50%, not on aspirin; global ischemic symptoms with stenosis < 50%; acute dissection, asymptomatic on heparin. Indications for carotid endarterectomy in asymptomatic good-risk patients performed by a surgeon whose surgical morbidity and mortality rate is less than 3% are as follows. (1) Proven: none. (As this statement went to press, the National Institute of Neurological Disorders and Stroke issued a clinical advisory stating that the Institute has halted the Asymptomatic Carotid Atherosclerosis Study (ACAS) because of a clear benefit in favor of surgery for patients with carotid stenosis > or = 60% as measured by diameter reduction. When the ACAS report is published, this indication will be recategorized as proven. (2) acceptable but not proven: stenosis > 75% by linear diameter; (3) uncertain; stenosis > 75% in a high-risk patient/surgeon (surgical morbidity and mortality rate > 3%), combined carotid/coronary operations, or ulcerative lesions without hemodynamically significant stenosis; (4) proven inappropriate: operations with a combined stroke morbidity and mortality > 5%.

Internal carotid artery surgery: ten-year results

The twofold purpose of this study was to compare the immediate results of surgery for lesions of the internal carotid artery in two series of patients operated on at 10-year intervals and to assess long-term results in the earliest series. Series I comprised 242 reconstructions in 220 patients (160 men and 60 women, mean age 64.4 years) performed between 1980 and 1982. Seventy patients (35%) were asymptomatic, 113 had monocular or hemispheric symptoms, and 30 had nonhemispheric symptoms. Contrast arteriograms revealed internal carotid artery stenosis of < 30% in 74 cases (30.6%), between 30% and 70% in 49 (20.2%), and > 70% in 119 (49.2%). Reconstruction was achieved by endarterectomy in 164 cases (67.8%), by vein graft in 75 cases (31%), and by other methods in 3 cases (1.2%). Postoperative mortality was 5% (11/110). Nonfatal postoperative stroke occurred in 1.8% (4/220) and transient ischemic attack in 0.5% (1 patient). All reconstructions were patent on postoperative control. The combined mortality/morbidity rate in patients in series II operated on between 1990 and 1991 was significantly lower, that is, 2.4% (4/170) vs. 6.8% (15/220) (p < 0.05). In series I, 11 patients (5%) were lost to follow-up and 124 were still alive at the beginning of the tenth postoperative year. Cumulative survival was 79 +/- 5.6% at 5 years and 60.9 +/- 6.7% at 10 years. The causes of late death were stroke in 7 cases, cardiovascular disease in 30 cases, cancer in 16 cases, and other causes in 20 cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Neurologic events following carotid endarterectomy: prediction of outcome

A total of 1572 carotid endarterectomies were performed at one institution between 1975 and 1987. One hundred five patients had early (< 3 weeks) neurologic events following carotid endarterectomy. Sixty-five patients had cerebral vascular accidents (CVAs) (4.1%), 14 patients had reversible ischemic neurologic deficits (0.9%), and 26 patients had transient ischemic attacks (1.7%). Eight patients died from CVAs (0.5%). The mean follow-up was 31 months (range 1 to 137 months) with a 5-year cumulative survival of 77%. The median time of occurrence of neurologic events was 4 hours. Ages, cerebral protection, patches, carotid occlusion time (mean 29 minutes), gender, and status of the contralateral carotid arteries were not predictors of outcome. Death from neurologic events increased significantly in patients who had preoperative CVAs compared with patients with preoperative transient neurologic deficits (p < 0.05). The time of occurrence of CVA after carotid endarterectomy affected outcome, and an early CVA (< 4 hours) was associated with a higher mortality at 30 days and at 4 months as a consequence of the initial CVA (p = 0.11). Patients who had a neurologic event more than 4 hours after surgery had a significantly better resolution of their symptoms (66%) compared with patients who had an early neurologic event (35%, p < 0.05). The long-term follow-up of the surviving patients demonstrated an improvement in neurologic function in 75% of the CVA group (36/48) and 92% (76/83) of all patients who had neurologic events in long-term follow-up.

Impact of changing attitudes in carotid surgery on community hospital practice

In 1985, institutional guidelines for the evaluation and performance of carotid surgery were established in our community hospital. During the 5-year period from 1985 through 1989, 159 carotid reconstructions were done. There were four major strokes (3%), one eventually resulting in death, with the second death in this series from a myocardial infarction (mortality 1%). The combined mortality/major stroke morbidity incidence was 3%. Three transient ischemic attacks (2%) postoperatively cleared promptly without residua. During the latter 1980s, an increasing number of vascular surgeons were doing less carotid surgery. Monitoring institutional quality assurance and individual surgeon performance within the community hospital is becoming a reality. Our experience with institutional guidelines for the evaluation and conduct of carotid surgery, together with an assessment of results and ongoing individual surgeon performance, is presented. Maintaining acceptable morbidity and mortality statistics can be enhanced by having a plan for assessment, management, and concurrent review.

Role of arteriography in the preoperative evaluation of carotid artery disease

This retrospective study was undertaken to determine the role of arteriography in the treatment of patients being considered for carotid endarterectomy. The results of preoperative classification of disease severity by duplex ultrasound and arteriography were compared, and the impact of arteriography on patient management was ascertained. We reviewed the records of 83 patients who had carotid surgery planned on the basis of their clinical history and duplex scan results and who then underwent arteriography. Duplex scan results agreed with the classification of stenosis by arteriography in 87% of evaluated sides and were within one category in 98%. In 87% of the cases reviewed, the clinical presentation and duplex scan findings were sufficient for appropriate patient management. In the instances that arteriography was useful (13%), the need for arteriography was evident when the duplex scan (1) was technically inadequate or equivocal; (2) showed an unusual distribution of disease, atypical anatomy, or a recurrent lesion; or (3) demonstrated an internal carotid artery with diameter-reducing stenosis of less than 50% in a patient with hemispheric neurologic symptoms despite antiplatelet therapy.

Perioperative stroke. Part I: General surgery, carotid artery disease, and carotid endarterectomy

Although stroke, defined as a focal neurological deficit lasting more than 24 hr, is uncommon in the perioperative period, its associated mortality and long-term disability are high. No large-scale data are available to identify the importance of recognized risk factors for stroke in the perioperative period. A review of the literature shows that the incidence and mechanism of its occurrence are influenced by the presence of cardiovascular disease and the type of surgery. The most common cause of perioperative stroke is embolism. In non-cardiac surgery, the incidence of perioperative stroke is higher among the elderly. Properly administered, controlled hypotension is associated with minimal risk of stroke. Cerebral vasospasm may be the cause of focal cerebral ischaemia in eclamptic patients, and the aggressive treatment of hypertension may exacerbate the neurological damage. The risk of stroke associated with carotid endarterectomy is closely related to the preoperative neurological presentation, and the experience of the surgical/anaesthetic team. Symptomatic cerebrovascular disease, acute stroke, asymptomatic carotid lesions, preoperative assessment of risk, local and general anaesthesia, cerebral protection and monitoring during carotid endarterectomy are discussed with reference to reducing the risk of perioperative stroke. Adequate monitoring and protection have minimized the risk of ischaemia from carotid clamping, and the major mechanism of stroke is embolization.

Carotid endarterectomy: a ten-year analysis of outcome and cost of treatment

Between 1978 and 1988, 215 patients with an average age of 67 years, underwent 246 carotid endarterectomies. Two hundred ten (85.4%) patients were symptomatic, and 36 (14.6%) were asymptomatic. Six patients (2.4%) had a postoperative stroke, and all had immediate reoperation. One of these patients died (30 day mortality rate, 0.4% for the series), and two (0.8%) recovered completely, whereas three (1.2%) had a mild permanent neurologic deficit. Two patients (0.8%) had nonfatal myocardial infarction. Mean follow-up of 42.2 months (range, 1 to 126 months) was achieved. At 5 and 8 years actuarial survival rates of 82% and 66% and stroke-free survival rates of 67% and 37% were observed. Actuarial stroke free rates of 90% at 5 and 8 years were noted. By introducing and observing guidelines that required preoperative study of most clearly defined classes of patients before admission for surgical treatment, the average length of stay for carotid endarterectomy was lowered from 9.5 days in the first 5 years of the study to 5.8 days in the second 5 years (p = 0.001). Average hospital charges, expressed in constant dollars, decreased from $3113 in the first 5 years to $2620 in the second 5 years (p = 0.02) despite an 88% inflationary increase in medical consumer price index. This experience shows that the length of hospitalization of patients with carotid endarterectomy can be reduced and the cost of admission lowered without untoward effect on perioperative morbidity and mortality rates.

Carotid endarterectomy in community practice: surgeon-specific versus institutional results

The efficacy of carotid endarterectomy in preventing stroke is clearly related to appropriate patient selection and low surgical morbidity and mortality. It has been suggested that since results at some centers are better than nationwide statistics, perhaps the operation should be limited to those institutions. In this paper we present an experience with carotid endarterectomy over the past twelve years. These 566 consecutive cases were performed by two vascular surgeons in a large metropolitan area using thirteen different hospitals ranging from 150 to 500 beds. Our mortality of 0.5% and permanent stroke incidence of 1.6% did not vary significantly from hospital to hospital. Where the results of surgical audits were available from the individual hospitals, the overall complication rates were significantly higher. We conclude that individual surgeons, not institutions, determine the efficacy of carotid endarterectomy in community practice.

Risk factors in carotid artery surgery: an evaluation of 414 operations

Four hundred and fourteen carotid reconstructions performed on 352 patients during the years 1971-82 were analysed retrospectively. Fifty-eight percent of the patients were operated on because of hemispheric transient ischaemic attacks (TIA). Twenty-eight percent had suffered a stroke before surgery. The overall combined mortality and morbidity was 7.7%. The procedure mortality was 2.9% with a slightly higher mortality i.e. 5.9% in the stroke group although not significantly higher than among non-stroke patients with a mortality of 1.4%. Patients of more than 70-years had a significantly higher operative mortality (11.1%) than the rest of the patients (1.7%). Non-fatal strokes occurred in 20 patients (4.8%). No correlation was found with the degree of stenosis of the contralateral artery.

Evaluation of a new classification of cerebrovascular disease: CHAT

A new scheme that classifies cerebrovascular disease on the basis of current and prior clinical symptoms, arteriographic findings, and target organ abnormalities has been evaluated. The scheme proved to be easy to learn and to use. Its utility was demonstrated by the previously unreported distinctions that became apparent when various patient subsets were analyzed according to the CHAT classification. These included an improved probability of stroke-free survival in patients operated on for brief strokes (transient ischemic attack) as opposed to temporary strokes (reversible ischemic neurologic deficit), and similarly improved survival probability in patients operated on for amaurosis fugax in comparison to those with carotid territory hemispheric transient ischemic attacks. The impact of multiple arterial lesions and positive computerized tomography scan findings appeared to be minimal with respect to both late stroke and survival in our preliminary observations. The simplicity and utility of the CHAT scheme make it a useful method to evaluate and report clinical experience with cerebrovascular disease.