Noninvasive assessment of stroke risk in asymptomatic and nonhemispheric patients with suspected carotid disease. Five-year follow-up of 294 unoperated and 81 operated patients

Carotid intraplaque haemorrhage: pathogenesis, histological classification, imaging methods and clinical value

Vulnerable carotid atherosclerotic plaques are characterised by several risk factors, such as inflammation, neovascularization and intraplaque haemorrhage (IPH). Vulnerable plaques can lead to ischemic events such as stroke. Many studies reported a relationship between IPH, plaque rupture, and ischemic stroke. Histology is the gold standard to evaluate IPH, but it required carotid endarterectomy (CEA) surgery to collect the tissue sample. In this context, several imaging methods can be used as a non-invasive way to evaluate plaque vulnerability and detect IPH. Most imaging studies showed that IPH is associated with plaque vulnerability and stroke, with magnetic resonance imaging (MRI) being the most sensitive and specific to detect IPH as a predictor of ischemic events. These conclusions are however still debated because of the limited number of patients included in these studies; further studies are required to better assess risks associated with different IPH stages. Moreover, IPH is implicated in plaque vulnerability with other risk factors which need to be considered to predict ischemic risk. In addition, MRI sequences standardization is required to compare results from different studies and agree on biomarkers that need to be considered to predict plaque rupture. In these circumstances, IPH detection by MRI could be an efficient clinical method to predict stroke. The goal of this review article is to first describe the pathophysiological process responsible for IPH, its histological detection in carotid plaques and its correlation with plaque rupture. The second part will discuss the benefits and limitations of imaging the carotid plaque, and finally the clinical interest of imaging IPH to predict plaque rupture, focusing on MRI-IPH.

Current Management of Extracranial Carotid Artery Disease

Stroke is the third most common cause of death in the United States. There are approximately 700,000 strokes/year; 80% are ischemic, and 20-30% of ischemic strokes are secondary to carotid disease. Carotid stenosis is traditionally treated by carotid endarterectomy (CEA). Multicenter, randomized, controlled trials have shown that surgery significantly reduces the risk of ipsilateral stroke in patients with severe symptomatic and asymptomatic carotid stenosis. Endovascular techniques for treating carotid stenosis have been developed over recent years. Carotid angioplasty and stenting (CAS) with cerebral protection has become an alternative to CEA for high-surgical-risk patients and the procedure of choice for stenoses inaccessible by surgery. In this review we summarize the existing data regarding the traditional state of management of extracranial carotid artery stenosis and compare these data to a critical analysis of the recent results of CAS.

Asymptomatic Carotid Stenosis and Risk of Stroke: A Natural History Study

In patients with asymptomatic carotid stenosis >70% diameter, the annual incidence of ipsilateral stroke is 3-4%. Multicentre randomised studies such as the asymptomatic carotid atherosclerosis study (ACAS) in the U.S.A. and the ACST in Europe aim to answer the question whether carotid endarterectomy can reduce the incidence of stroke in such patients. If the surgical risk is too close to benefit or if a high proportion of patients not at risk of stroke are entered into the ACAS or ACST studies, the latter may fail to demonstrate the benefit of carotid endarterectomy (CE). The need to identify a high risk stroke group (ipsilateral stroke >7% per annum) with randomisation of this group to a subsequent study will then become apparent. If the ACAS and ACST studies indicate that the risk of stroke is reduced by 50% (i.e., from 4 to 2%), it has been calculated that the cost of preventing one stroke will be 1.2 million US dollars because of the large number of operations required. It will still be necessary to identify a high-risk group or, better, a low-risk group in order to spare many patients unnecessary operation. A multicentre, natural history study has been set up under the auspices of the International Union of Angiology and monitored from St Mary's Hospital Medical School in London with over 50 centres taking part. Patients with asymptomatic carotid stenosis 50-70% and 70-90% are entered in a ratio of 1 to 2, a number of noninvasive tests are performed, and the patients are followed for 5 years. The tests performed are (a) Grading the degree of internal carotid stenosis using duplex scanning; (b) grading the opposite side; (c) plaque characterisation; (d) presence of ultrasonic ulceration; (e) plaque thickness (mm); (f) cerebral reactivity to CO2using velocity of internal carotid artery and (optional) middle cerebral artery ; (g) CT brain scan for the presence of silent infarction ; (h) intima-media thickness of the common carotid; and (i) identification of conventional risk factors: hypertension, hypercholeterolaemia, smoking, family history, diabetes. The key end points are stroke (including fatal stroke) and ipsilateral stroke. Patients who die from cardiovascular death other than stroke or noncardiovascular death and patients who develop hemispheric transient ischaemic attacks followed by CE are considered to have reached an exit end point. Because this is a natural history study, the clinician in charge of all patients is free to treat them in any way considered appropriate. Patients in the Medical Limb of the ACST study may be entered into the Natural History (ACSRS) study.

Decision analysis and carotid endarterectomy

A data base and a framework for clinical decision analysis are provided to enable the clinician to determine the value of carotid endarterectomy in patients with transient ischemic attacks. This approach permits optimal utilization of available data, maximizes the value of informed consent by clearly delineating areas of physician and patient expertise, and permits a quantitative assessment of the impact of uncertainty regarding underlying variables on decision outcome. The results of the analysis indicate that (a) the late nonstroke death rate has little effect on the value of endarterectomy, (b) the patient's relative valuation of stroke and immediate versus delayed death are among the most crucial variables underlying the value of endarterectomy, and (c) endarterectomy may be indicated in certain patients with transient ischemic attacks, but when its utility is measured in terms of value rendered to the patient, its relative cost may be greater than that of certain life-saving operations such as heart or liver transplant.

Medical (Nonsurgical) Intervention Alone Is Now Best for Prevention of Stroke Associated With Asymptomatic Severe Carotid Stenosis

Significant advances in vascular disease medical intervention since large randomized trials for asymptomatic severe carotid stenosis were conducted (1983–2003) have prompted doubt over current expectations of a surgical benefit. In this systematic review and analysis of published data it was found that rates of ipsilateral and any-territory stroke (+/−TIA), with medical intervention alone, have fallen significantly since the mid-1980s, with recent estimates overlapping those of operated patients in randomized trials. However, current medical intervention alone was estimated at least 3 to 8 times more cost-effective. In conclusion, current vascular disease medical intervention alone is now best for stroke prevention associated with asymptomatic severe carotid stenosis given this new evidence, other cardiovascular benefits, and because high-risk patients who benefit from additional carotid surgery or angioplasty/stenting cannot be identified.

Carotid plaque morphology correlates with presenting symptomatology

PURPOSE

In carotid artery disease, correlation of carotid plaque morphology with the patient's presenting symptoms has drawn conflicting conclusions. The purpose of this series was to correlate carotid plaque characteristics with the presenting symptoms from a large cohort of patients who underwent operation for carotid artery disease.

METHODS

From a series of 1252 consecutive patients who underwent carotid endarterectomy, presenting symptoms were divided into three groups: transiently symptomatic (transient ischemic attack [TIA] or amaurosis fugax), prior stroke, and asymptomatic. Plaque characteristics, including ulceration, intraplaque hemorrhage, and degree of stenosis, were recorded prospectively for 1008 procedures. All endarterectomy specimens were inspected during the procedure, and plaque characteristics were recorded immediately after operation.

RESULTS

There was a higher incidence of plaque ulceration in the transiently symptomatic and prior stroke groups (391 of 508 [77%] and 91 of 115 [79%]) than in the asymptomatic cohort (231 of 385 [60%]; p < 0.0001, chi2 test). There was no significant difference in the incidence of plaque hemorrhage between the transiently symptomatic and prior stroke patients compared with the asymptomatic patients. There was no statistical difference for ulcerated plaque or plaque hemorrhage between the transiently symptomatic and prior stroke group. Intraplaque hemorrhage occurred more frequently in patients with high-grade stenosis (90% to 99%) than in those with less than 90% stenosis (202 of 299 [68%] versus 97 of 299 [32%]; p = 0.01, chi2 test).

CONCLUSIONS

On gross examination of the carotid specimen in the operating room, plaque ulceration correlates with an initial presentation of amaurosis fugax, TIA, or prior stroke compared with patients operated on for asymptomatic disease. The presence of intraplaque hemorrhage is associated with more advanced stenosis of the internal carotid artery. These findings suggest that plaque morphology does play an important role in the presentation of carotid artery disease.

Prophylactic carotid endarterectomy without arteriography in patients without hemispheric symptoms: surgical morbidity and mortality and long-term follow-up

Between January 1980 and December 1992, 75 prophylactic carotid endarterectomies (CE) were performed on 72 asymptomatic patients presenting high-grade stenosis of the internal carotid artery (ICA). In all patients preoperative assessment consisted of continuous Doppler or duplex scanning. There were 33 women and 39 men with a mean age of 66 +/- 7 years. Surgical exploration confirmed high-grade ICA stenosis in all patients. Mean transstenotic gradient and residual carotid stump pressure determined in 24 patients were 34 +/- 25 mmHg and 51 +/- 20 mmHg, respectively. Combined operative mortality and neurologic morbidity was 1.3% (one death, no permanent neurologic defect). At 5 years, 74% +/- 8% of patients were free of neurologic complications, 89% +/- 8% of patients were free of neurologic complications affecting the ipsilateral cerebral hemisphere, and actuarial survival was 75% +/- 8%. Most deaths were due to heart-related causes. Multivariate analysis showed that hypertension, age, recurrent stenosis, and contralateral stenosis greater than 50% were risk factors for neurologic complications. When only ipsilateral complications were considered, only hypertension was a risk factor. Based on the results of this study, we conclude that prophylactic CE based only on continuous Doppler or duplex scanning is a reliable and safe procedure. Prophylactic CE was effective in avoiding long-term neurologic complications due to ipsilateral hemispheric lesions. However, the higher incidence of contralateral neurologic complications suggests that close surveillance of contralateral lesions is necessary.

The identification of the high risk carotid plaque

OBJECTIVE

To determine the influence of carotid plaque morphology and severity of stenosis on symptoms of cerebrovascular disease and cerebral infarction.

PATIENTS AND METHODS

One hundred and ninety patients with 329 carotid plaques producing 50-99% stenosis were studied. Carotid plaque echogenicity on ultrasonography was evaluated using computerised measurement of the median of the overall grey scale content (GSM). Heterogeneity was evaluated as the difference between the GSMs of the most echogenic and the most echolucent areas within each plaque and expressed as the heterogeneity index (HI). All patients had a CT brain scan and the presence of ipsilateral cerebral infarction noted.

RESULTS

Cerebral infarction was more common in symptomatic than asymptomatic plaques (42% vs. 29%, p<0.02) and in echolucent than echogenic plaques (mean GSM of 37.8 vs. 29.7, p<0.01). Plaques with GSM below or equal to 32 were associated with a higher incidence of cerebral infarction as compared to those above this level, this was significant in both symptomatic and asymptomatic plaques. Symptomatic carotid plaque were less heterogenous than asymptomatic plaques. Plaques associated with cerebral infarction were less heterogenous than those not associated with infarction.

CONCLUSION

This study has shown that the identification of the high risk carotid plaques, i.e. those associated with a high incidence of cerebral infarction is possible both in symptomatic and asymptomatic patients. The potential of such analysis in the identification of patients with asymptomatic carotid stenosis with high and low risk of stroke should be explored in a natural history study.

Asymptomatic cervical artery stenoses in Moscow

The risk of stroke related to asymptomatic carotid artery stenosis is known to be increased in high-grade or rapidly progressive stenosis. Information of the prevalence in the general population is required for the recommendation of screening methods to detect patients needing prophylactic treatment. We studied the prevalence and the grade of severity of extracranial carotid and vertebral artery obstructions by means of Doppler sonography in 529 asymptomatic Russians (m: 343, f: 186; 36-84 years, mean: 58.4 years) living in Moscow city. Internal carotid artery obstructions of more than 50% stenosis were present in 22 (= 4.2%) subjects, 8 of them (1.5%) had bilateral lesions. Appropriate abnormal findings in vertebral arteries were found in 11 (= 2.1%) subjects, in 1 of them bilaterally. Affection of both the carotid and the vertebral arteries was noted in 4(= 0.8%) individuals. There were no sexual differences. The risk factor which correlated most significantly with cervical arterial lesions was hypertension. Carotid lesions were also significantly associated with age and smoking, but not with diabetes or hyperlipoproteinemia. The prevalence of cervical artery stenoses was found to be lower than in western reports, which may be due to different technical equipment and different study design.

Carotid plaque morphology: a review

The recent North American Symptomatic Carotid Endarterectomy Trial has answered fairly conclusively the questions concerning the optimal management of patients with symptoms who have a > 70% stenosis of the internal carotid artery. It has also had the effect of refocusing attention on carotid pathology. The main question still to be answered is whether surgical management is the optimum treatment for other groups of patients with carotid disease. From various studies done on the natural history of carotid plaques it is apparent that there are subgroups who may benefit from surgery, namely those who will progress to stroke if not treated. The problem comes in identifying these subgroups by the factors which cause them to progress. This paper aims to review the role that plaque morphology has in the development of symptoms and whether it should be included with degree of stenosis in assessing the risk of a carotid plaque. The non-invasive assessment of plaque morphology is also reviewed. The evidence from this review does not support the use of plaque morphology as a discriminating factor for carotid endarterectomy at present.

The natural history of moderate (50% to 79%) internal carotid artery stenosis in symptomatic, nonhemispheric, and asymptomatic patients

PURPOSE

This study was undertaken to determine the incidence of disease progression of moderate (50% to 79%) internal carotid artery stenosis in patients with symptoms, patients with nonhemispheric symptoms, and symptom-free patients and to define the risk of development of new neurologic events in each group.

METHODS

Over a 6-year period, 272 patients with moderate internal carotid artery stenoses were monitored for a mean of 44 months with color-flow duplex scanning (CFS). At the time of the initial scan, 142 patients were symptom free, 87 had experienced transient ischemic attacks, amaurosis fugax, or mild strokes, and 43 had ill-defined nonhemispheric symptoms. The average number of follow-up scans was 2.4 per patient (range 1 to 11).

RESULTS

During follow-up, 23 (26%) of the patients with symptoms, 17 (40%) of the patients with nonhemispheric symptoms, and 30 (21%) of the symptom-free patients had development of additional neurologic symptoms. Life-table comparison of ipsilateral ischemic events showed a significantly (p = 0.03) higher cumulative rate in the symptomatic group (20%) than in the asymptomatic group (7%) at 2 years. Mean annual stroke rates were 6% and 2% in patients in the symptomatic and asymptomatic groups, respectively. None of the patients in the nonhemispheric group had a stroke within 4 years of the initial study. Disease progression occurred in 16% of the patients. In the asymptomatic group, ipsilateral stroke occurred more frequently (p = 0.0001) in patients with disease progression (25%) than in patients with stable lesions (1%). CFS detected disease progression in 19 (79%) of 24 patients before the artery occluded or stroke occurred. In patients with symptoms, stroke was more frequent (p = 0.02) in patients with six or more risk factors (29%) than in those with five or fewer risk factors (7%).

CONCLUSION

Although the risk of stroke is less in patients with moderate stenosis than it is in patients with severely stenotic lesions, symptom-free patients with advancing disease and patients with symptoms and multiple risk factors are at increased risk for development of neurologic events. These findings support the use of CFS to monitor patients with carotid artery disease and suggest that a more aggressive surgical approach may be indicated in selected patients with moderate carotid artery stenosis.

Accuracy of duplex versus angiography in patients undergoing carotid surgery

The operative findings of 23 carotid arteries were compared with pre-operative duplex scans and angiography. Both duplex and angiography had a high degree of accuracy in detecting haemodynamically significant lesions of 50-99% (88 and 92%, respectively). Their accuracy, however, in correctly predicting the grade of stenosis was significantly lower; 30 and 48%, respectively (P < 0.001). They each exhibited an accuracy of 70% and 78%, respectively, in the detection of ulceration. Overall, both duplex and angiography displayed an accuracy of 87% in indicating the proper management course. The combination of both investigations increased this accuracy to 94.6%. In severely stenotic lesions, duplex to rule out occlusion was not reliable. On statistical analysis, there was no difference between duplex and angiography in predicting haemodynamically significant lesions of 50-99%, estimating the grade of stenosis, the detection of ulceration, or indicating the proper management course. In most situations, duplex alone equalled the accuracy of angiography in the pre-operative assessment of patients for carotid surgery. For stenotic lesions of > 90%, however, we recommend supplemental angiography to rule out occlusion.

Immediate and long-term results of carotid endarterectomy for asymptomatic high-grade stenosis

We examined the operative risks and long-term results of carotid endarterectomy for asymptomatic patients in terms of stroke, death, and recurrent stenosis. The results of a nonrandomized study with a follow-up of 1 to 104 months (mean 46 months) is reported. A tertiary referral center served as the setting for this report. One hundred consecutive patients with severe but asymptomatic carotid artery stenosis out of a total of 514 patients undergoing carotid endarterectomy were entered into this study. The severity of carotid disease was determined by duplex scanning and confirmed arteriographically. No patients were lost to follow-up after surgery. Eighty-nine operations (77%) were done under cervical block anesthesia and all arteries were closed with saphenous vein patches. Life-table analysis showed that the stroke-free rate at 5 years was 96.3% with an ipsilateral stroke-free rate of 98.2%. The 5-year overall survival rate was 78.2% with a stroke-free survival rate of 75%. Carotid endarterectomy can be performed safely for asymptomatic patients believed to be at risk for stroke. The potential for early death due to myocardial disease, late stroke, and recurrent stenosis do not justify advising patients against undergoing prophylactic carotid endarterectomy for asymptomatic high-grade stenosis.

The use of expected value as an aid to decisions regarding anticoagulation in patients with atrial fibrillation

BACKGROUND

The method described provides a rational means for determining whether to institute chronic anticoagulation to prevent stroke in patients with chronic atrial fibrillation under a variety of clinical circumstances.

SUMMARY OF COMMENT

The concept of expected value is used in conjunction with data from clinical studies to define the net value of anticoagulation to the patient. A full year of anticoagulation is warranted in patients with recent stroke or transient ischemic attack thought to be due to cardiogenic embolism who feel that stroke is a very serious event with nearly as much disvalue as death. If stroke has a lesser degree of negative value to the patient, or it is uncertain whether the stroke was in a large-vessel distribution, or it is uncertain whether a large-vessel distribution stroke was due to cardiogenic embolism, 6 months or less of anticoagulation may be warranted. Indefinite anticoagulation is justifiable in most patients with chronic atrial fibrillation without a history of stroke or transient ischemic attack but may be contraindicated in certain patients at extremely low risk for embolism and in patients who place a low value on stroke relative to death and who have a modest increase in risk for fatal hemorrhage.

CONCLUSIONS

The method described provides a means readily usable by clinicians to make anticoagulation decisions in patients with chronic atrial fibrillation that will address risk-benefit tradeoffs with somewhat greater precision than current approaches.

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)

Efficacy of carotid endarterectomy for asymptomatic carotid stenosis. The Veterans Affairs Cooperative Study Group

BACKGROUND

The efficacy of carotid endarterectomy in patients with asymptomatic carotid stenosis has not been confirmed in randomized clinical trials, despite the widespread use of operative intervention in such patients.

METHODS

We conducted a multicenter clinical trial at 11 Veterans Affairs medical centers to determine the effect of carotid endarterectomy on the combined incidence of transient ischemic attack, transient monocular blindness, and stroke. We studied 444 men with asymptomatic carotid stenosis shown arteriographically to reduce the diameter of the arterial lumen by 50 percent or more. The patients were randomly assigned to optimal medical treatment including antiplatelet medication (aspirin) plus carotid endarterectomy (the surgical group; 211 patients) or optimal medical treatment alone (the medical group; 233 patients). All the patients at each center were followed independently by a vascular surgeon and a neurologist for a mean of 47.9 months.

RESULTS

The combined incidence of ipsilateral neurologic events was 8.0 percent in the surgical group and 20.6 percent in the medical group (P < 0.001), giving a relative risk (for the surgical group vs. the medical group) of 0.38 (95 percent confidence interval, 0.22 to 0.67). The incidence of ipsilateral stroke alone was 4.7 percent in the surgical group and 9.4 percent in the medical group. An analysis of stroke and death combined within the first 30 postoperative days showed no significant differences. Nor were there significant differences between groups in an analysis of all strokes and deaths (surgical, 41.2 percent; medical, 44.2 percent; relative risk, 0.92; 95 percent confidence interval, 0.69 to 1.22). Overall mortality, including postoperative deaths, was primarily due to coronary atherosclerosis.

CONCLUSIONS

Carotid endarterectomy reduced the overall incidence of ipsilateral neurologic events in a selected group of male patients with asymptomatic carotid stenosis. We did not find a significant influence of carotid endarterectomy on the combined incidence of stroke and death, but because of the size of our sample, a modest effect could not be excluded.

The influence of contralateral disease on the natural history of nonoperated significant carotid stenosis

The influence of contralateral disease on the natural history of ipsilateral nonoperated carotid stenosis greater than 50% was analyzed in 90 carotid arteries imaged by contrast arteriography or duplex scanning with a mean follow-up of 23.6 months. Ipsilateral stenosis was greater than 80% in 24 arteries and 50-79% in 66 arteries. Contralateral disease was present in 30 (Group I) and absent in 60 (Group II) patients. In Group I, the contralateral disease consisted of total occlusion in nine (30%), greater than 80% stenosis in five (17%), 50-79% stenosis in 12 (40%) with a mean of 78.6%. No significant difference existed in the incidence of initially asymptomatic vessels (57% versus 67%), stroke (13% versus 2%), or transient ischemic attack (17% each) between Groups I and II on the ipsilateral side (p greater than .05). New ipsilateral neurologic events occurred significantly more often in arteries with greater than 80% ipsilateral stenosis than those with 50-79% stenosis (p less than .02). The incidence of subsequent ipsilateral neurologic events (37% versus 22%), strokes, or transient ischemic attacks (20% versus 13%) was no different in Groups I and II, respectively (p greater than .05). Combined ipsilateral and contralateral neurologic events occurred significantly more often in patients with contralateral disease (p less than .05). Whereas in Group I, new ipsilateral symptoms were significantly more common in initially symptomatic vessels compared to asymptomatic ones (61.5% versus 17.6%, p less than .04), no such difference existed in Group II.

Therapy for isolated, low and high grade symptomatic carotid artery stenosis

This study evaluates whether medical therapy alone can achieve satisfactory results in the treatment of low grade carotid stenosis or ulcerated plaques. Out of 525 patients presenting with transient or minor strokes, 64 were found with unilateral extracranial vascular disease as the sole potential source for their neurological symptoms. Utilizing arteriographic criteria, 35 patients with ulcerated plaques or carotid artery stenosis of less than 50% luminal artery diameter were treated conservatively with aspirin and dipyridamole (300 mg/day each). Twenty-nine patients with unilateral internal carotid artery stenosis of greater than 50% luminal artery diameter were treated by means of carotid endarterectomy. Follow-up in the two groups for a mean period of 24-26 months revealed no major strokes or neurological deaths in either group. Myocardial infarction was the major cause of death. Two patients developed subsequent transient ischemic attacks, and one a minor stroke with total recovery in the conservatively treated group. All became asymptomatic when warfarin replaced aspirin therapy. The findings in this study confirmed that "low grade" stenoses can be safely treated by medical measures alone.

A prospective study of vein patch angioplasty during carotid endarterectomy. Three-year results for 801 patients and 917 operations

From 1983 through 1985, 801 consecutive patients (mean age: 66 years) underwent 917 primary carotid endarterectomies at the Cleveland Clinic. Conventional arteriotomy closure was performed during 483 operations, while patch angioplasty using a distal segment of saphenous vein was employed in 434. Preoperative risk factors, surgical management, and antiplatelet therapy were equivalent in the vein patch (VP) and nonpatch (NP) groups. Early results were evaluated by intravenous angiography (DSA) in 715 patients (89%), and 332 reconstructions (36%) have been reassessed by objective imaging during a mean follow-up interval of 21 months. Ischemic strokes occurred after 18 (1.9%) of the 917 procedures (0.7% VP, 3.1% NP; p = 0.0084), and symptomatic (N = 9) or unsuspected (N = 8) thrombosis of the internal carotid artery was confirmed by neck exploration or routine DSA after 1.9% of all operations (0.5% VP, 3.1% NP; p = 0.0027). Only ten patients (1.2%) have required reoperations for severe recurrent lesions, but the cumulative 3-year incidence of new defects (greater than or equal to 30% stenosis) documented by objective studies in the VP and NP groups was 9% and 31%, respectively (p = 0.0066). These results strongly suggest that VP angioplasty enhances the safety and durability of carotid endarterectomy.

Surgical versus nonoperative treatment of asymptomatic carotid stenosis. 290 patients documented by intravenous angiography

From 1980 through 1982, intravenous extracranial digital subtraction angiography (DSA) was performed in 6684 patients at the Cleveland Clinic. Of these, 290 previously unoperated patients had asymptomatic carotid stenosis exceeding 50% of lumen diameter on unequivocal DSA studies. Either the presence or the absence of carotid bruits substantially misrepresented the severity of angiographic stenosis on approximately 30% of sides. Nonoperative management was employed in 195 patients, including 104 (53%) who received antiplatelet therapy, while another group of 95 patients underwent prophylactic carotid endarterectomy. During mean follow-up intervals of 33-38 months, surgical treatment significantly reduced the cumulative incidence of subsequent neurologic events in men (p = 0.05). Statistically unconfirmed trends also suggested that carotid endarterectomy tended to prevent late strokes in subsets of patients with greater than 70% stenosis or bilateral carotid lesions. The overall stroke rate for women was higher in the surgical group (p = 0.03), in part because of their unusual risk for perioperative complications (9%) in this particular series.