Natural history and management of the asymptomatic, moderately stenotic internal carotid artery

Contemporary Treatment of the Asymptomatic Carotid Patient

Stroke is a persistent leading cause of morbidity and mortality, and carotid artery atherosclerosis remains a treatable cause of future stroke. Although most patients with asymptomatic carotid artery disease may be at a relatively low risk for future stroke, most completed strokes are unheralded; thus, the identification and appropriate treatment of patients with asymptomatic carotid artery disease remains a critical part of overall stroke prevention. Select patients with asymptomatic carotid artery stenosis with an increased risk of future stroke based on the degree of stenosis and other imaging or patient-related characteristics are appropriate to consider for carotid artery intervention.

Survey of Current Management Practices for Carotid Webs

Background: Carotid webs are thick, fibrous intimal bands that appear as intraluminal shelf-like defects at the carotid bifurcation on vascular imaging. These lesions are a potential underrecognized cause of cryptogenic ischemic stroke. Although the recognition of carotid webs has increased, no evidence-based treatment guidelines are available. We surveyed subspecialists across multiple neurologic disciplines to assess the state of current clinical practice. Methods: An 8-question multiple-choice style survey of neurologists and radiologists assessed familiarity with this disease entity, preferred imaging modalities, and management strategies for asymptomatic and symptomatic (producing stroke) carotid webs. Responses were collected through SurveyMonkey software via anonymous responses to a posted survey link on the Society of Neurointerventional Surgery website in addition to invitation emails sent to colleagues in corresponding fields. Results: Of the 74 total respondents, 64% identified as neurointerventionalists. Respondents identified computed tomography angiography as the most commonly used imaging modality to place carotid webs in the differential diagnosis (57% of respondents' preference), while conventional digital subtraction angiogram was the preferred modality to confirm a web (54% of respondents' preference). Respondents preferred single and dual antiplatelet therapy to manage asymptomatic and acute stroke-producing carotid webs, while invasive treatment was most commonly sought for webs producing recurrent strokes. Conclusion: Familiarity with carotid webs varied across subspecialties. We found some consensus among respondents on the imaging modality preferred to identify webs, on asymptomatic carotid web management, and on recurrently symptomatic (multiple strokes) carotid web management. Less consistency was seen regarding preferences for confirmatory imaging and management of acutely symptomatic (initial stroke) carotid webs.

Carotid Artery Endarterectomy in the Octogenarian: A Community Hospital Experience

Between May 1995 and April 1998 three vascular surgeons performed 310 consecutive primary carotid endarterectomies (CEAs) in a 224-bed community hospital. Seventy-six CEAs were performed in octogenarians (Group 1) and 234 CEAs were performed in nonoctogenarians (Group 2). Demographic information, indication for surgery, and outcomes were compared. There were no strokes or deaths in Group 1; there was a single death and three strokes in Group 2. The overall rates of death, stroke, and combined stroke and death were 0.3%, 1%, and 1% respectively. No statistically significant difference existed in rates of morbidity and mortality in Groups 1 and 2. On follow-up (mean = 18 months), 94% of the patients were alive without stroke, 5% were dead, and 1% were alive with stroke. These data demonstrate that CEA can be performed safely in the octogenarian in the community hospital setting.

Carotid atherosclerosis progression and cerebrovascular events in patients with diabetes

AIM

Carotid atherosclerosis progression is associated with a higher risk of cerebrovascular events but there is no specific data for diabetes. We assessed in a cohort of patients with diabetes the rate of atherosclerosis progression by Doppler ultrasonography and the association with cerebrovascular events.

METHODS

We analyzed a retrospective cohort of 342 patients with a mean duration of diabetes of 13.6 ± 10.6 years. The mean delay between the first and last Doppler ultrasonography was 6.4 ± 4.6 years, with a mean of 3.4 examinations per person. Cerebrovascular events were noted.

RESULTS

A progression of carotid atherosclerosis was observed in 20.1% of cases. No factor was significantly associated with progression. A prophylactic carotid endarterectomy was performed on 6 of the 27 patients with a stenosis ≥50%. A cerebrovascular event occurred in 1.2% of patients; none of them had carotid atherosclerosis progression.

CONCLUSIONS

Carotid atherosclerosis progression in patients with diabetes is frequent but surgical treatment and cerebrovascular events are low. The benefit of a systematic follow-up of carotid atherosclerosis seems limited.

Progression of moderate-to-severe carotid disease

OBJECTIVE

Our goals were to investigate the degree to which patient demographics, risk factors, laboratory data, and medications influence moderate carotid disease progression among patients with asymptomatic moderate carotid disease and whether such associations are solely based on how progression is defined. In addition, we aimed to establish optimal threshold criteria to categorize patients at high risk of progression.

METHODS

In this retrospective study, 621 arteries were evaluated for internal carotid artery (ICA) stenosis between January 1997 and January 2014 and were determined to have moderate (50%-79%) stenosis via color duplex ultrasonography. "Moderate stenosis" was defined as an ICA peak systolic velocity (PSV) ≥120 cm/s and a diastolic ICA velocity <140 cm/s. Kaplan-Meier analysis of the time to progression was conducted using three independent end points: PSV ≥230 cm/s (liberal criterion); ICA/common carotid artery (CCA) ratio ≥4.0 (moderate criterion), and diastolic ICA velocity ≥140 cm/s (strict criterion). Kaplan-Meier survival curves were generated, and multivariate analysis was performed using Cox regression models. Risk stratification criteria were based on optimal sensitivity and specificity generated from receiver operating characteristic (ROC) curve analysis.

RESULTS

The overall rate of progression was 28.5%, 21.1%, or 5.1% of study-eligible arteries over 5 years using liberal, moderate, or strict criterion, respectively. Using liberal criterion, multivariate analysis suggested that initial PSV ≥200 cm/s, ICA/CCA ratio ≥3, and male gender were significantly associated with progression. Using the moderate criterion, multivariate analysis revealed that initial PSV ≥200 cm/s, ICA/CCA ratio ≥3, age, and male gender were significantly associated with progression. Using the strict criterion, multivariate analysis revealed that initial PSV ≥200 cm/s was the only statistically significant predictor of progression. No additional patient demographics, comorbidities, initial laboratory values, or medications consistently influenced disease progression across any criteria in our study. ROC analysis suggests PSV ≥165 cm/s is an ideal threshold value for the categorization of high risk patients, as this resulted in an optimal screening sensitivity of nearly 91% and a specificity of 59% over 2 years.

CONCLUSIONS

The timing and incidence of carotid disease progression depends on the definition of disease progression. Among all three criteria, only severity of disease at initial presentation reliably predicted progression. Based on the results of our ROC curve analysis, we propose that an initial ICA PSV ≥165 cm/s (sensitivity: 90.7%, specificity: 58.7%) represents a reasonable value for defining high progression risk over a 2-year interval.

Carotid revascularization: risks and benefits

Despite a decline during the recent decades in stroke-related death, the incidence of stroke has remained unchanged or slightly increased, and extracranial carotid artery stenosis is implicated in 20%–30% of all strokes. Medical therapy and risk factor modification are first-line therapies for all patients with carotid occlusive disease. Evidence for the treatment of patients with symptomatic carotid stenosis greater than 70% with either carotid artery stenting (CAS) or carotid endarterectomy (CEA) is compelling, and several trials have demonstrated a benefit to carotid revascularization in the symptomatic patient population. Asymptomatic carotid stenosis is more controversial, with the largest trials only demonstrating a 1% per year risk stroke reduction with CEA. Although there are sufficient data to advocate for aggressive medical therapy as the primary mode of treatment for asymptomatic carotid stenosis, there are also data to suggest that certain patient populations will benefit from a stroke risk reduction with carotid revascularization. In the United States, consensus and practice guidelines dictate that CEA is reasonable in patients with high-grade asymptomatic stenosis, a reasonable life expectancy, and perioperative risk of less than 3%. Regarding CAS versus CEA, the best-available evidence demonstrates no difference between the two procedures in early perioperative stroke, myocardial infarction, or death, and no difference in 4-year ipsilateral stroke risk. However, because of the higher perioperative risks of stroke in patients undergoing CAS, particularly in symptomatic, female, or elderly patients, it is difficult to recommend CAS over CEA except in populations with prohibitive cardiac risk, previous carotid surgery, or prior neck radiation. Current treatment paradigms are based on identifying the magnitude of perioperative risk in patient subsets and on using predictive factors to stratify patients with high-risk asymptomatic stenosis.

[Carotid artery screening for stroke prevention]

CLINICAL/METHODICAL ISSUE

The aim was to identify the risk of impending stroke originating from diseases of the carotid artery.

STANDARD RADIOLOGICAL METHODS

Duplex scanning is the standard method for clinical examination of carotid arteries.

METHODICAL INNOVATIONS

By implementing the new standardized German Society for Ultrasound in Medicine (DEGUM) criteria, ultrasound examination enables reliable grading of carotid artery disease and identification of the progression of stenosis.

PERFORMANCE

Current guidelines recommend duplex scanning as the standard method. In consequence of finding atherosclerosis, intensive monitoring and therapy of cardiovascular risk factors is mandatory. In cases showing rapid progression of stenosis or a very high degree of stenosis indicating increased risk of stroke, carotid endarterectomy or stenting is warranted.

ACHIEVEMENTS

Detection of carotid artery atherosclerosis is uncomplicated and the method is not demanding; however, identification of high-risk carotid disease by exact grading of carotid stenosis requires investigation by an experienced examiner.

PRACTICAL RECOMMENDATIONS

Screening is recommended for patients exhibiting cardiovascular risk factors but is not recommended for the general population. On detection of carotid stenosis an exact grading of stenosis by an experienced examiner is absolutely essential.

Neuroimaging of the vulnerable plaque

Plaque vulnerability due to inflammation has been shown to be a participating factor in the degenerative process in the arterial wall that contributes to stenosis and embolism. This is believed to have an important role to play also in the genesis of stroke or cerebrovascular diseases. In order to appropriately screen patients for treatment, there is an absolute need to directly or indirectly visualize both the normal carotid and the suspected plaque. This can be done with a variety of techniques ranging from ultrasound to computed tomography (CT) and magnetic resonance imaging (MRI). In addition to angiographic techniques, direct imaging of the plaque can be done either by ultrasound or by the so-called molecular imaging techniques, i.e. positron emission tomography (PET). These findings, together with other clinical and paraclinical parameters should finally guide the therapeutic choice.

[Natural history of moderate-degree carotid stenosis in patients with peripheral artery disease]

BACKGROUND AND OBJECTIVE

To understand the evolution of moderate asymptomatic carotid stenosis, the factors that influence its progression and the related morbimortality.

PATIENTS AND METHODS

Retrospective observational study of 133 patients with asymptomatic carotid stenosis between 50-69% in one or both carotids between 2002 and 2009. Included patients were subjected to screening for peripheral arterial disease (PAD), aneurysmal disease or carotid bruit. The monitoring was carried out using an annual duplex scan. The rate of progression, the variables related to this, the appearance of neurological events, and global and cardiovascular mortality were evaluated. Descriptive studies, univariate analysis (chi-squared test and Student's t-test), multivariate analysis (logistic regression), and survival curves (Log-Rank test) were carried out.

RESULTS

With an average time of monitoring: 30.8 ± 1.7 months, stenosis progression was observed in 33% of the patients, with an average progression time of 31.3 ± 2.7 months. Greater progression was observed in the subgroup of patients with PAD and ischemic heart disease (odds ratio [OR] 2.84, confidence interval [CI] 95% 1.14-7.03). In the multivariate analysis only the PAD was identified as a risk factor for progression (P=.043). The group of patients with progression showed greater rates of neurological events: 15 vs. 1.6% (P=.01), greater global mortality: 15 vs. 3% (P=.04), and greater cardiovascular mortality: 12.1 vs. 1.5% (P=.03).

CONCLUSIONS

The progression of asymptomatic carotid stenosis between 50-69% is common in patients subjected to screening, especially in those with a history of ischaemic heart disease and/or PAD. This progression is associated with an increased rate of cardiovascular complications. For this reason, we recommend clinical and echographic follow-up of these patients.

Asymptomatic carotid artery stenosis and the risk of ischemic stroke according to subtype in patients with clinical manifest arterial disease

BACKGROUND AND PURPOSE

Because best medical treatment is improving, the risk of stroke in asymptomatic carotid artery stenosis (ACAS) may decline. We evaluated the risk of ischemic stroke and stratified it according to stroke subtype in patients with ACAS during long-term follow-up.

METHODS

In total, 4319 consecutive patients in the Second Manifestations of Arterial disease study with clinically manifest arterial disease or specific risk factors, but without a history of cerebrovascular disease, were included. Degree of stenosis was evaluated with duplex ultrasound scanning. Strokes during follow-up were classified according to subtype. Cox-proportional hazard-regression models were used to evaluate the relationship between ACAS and future stroke.

RESULTS

We identified 293 (6.8%) patients with ACAS 50% to 99%, of whom 193 had 70% to 99% stenosis. In these subgroups, mean follow-up was 6.2 and 6.0 years, respectively. In total, 94 ischemic strokes occurred, of which 8 in ACAS 50% to 99% patients. The any territory annual ischemic stroke risk was 0.4% in 50% to 99% ACAS and 0.5% per year for 70% to 99% ACAS patients. The risk of ischemic stroke was not significantly increased in patients with ACAS 70% to 99% (hazard ratio, 1.5; 95% confidence interval, 0.7-3.5). Patients with ACAS 50% to 99% and ACAS 70% to 99% tended to have nonsignificantly more large vessel disease strokes (hazard ratio, 1.5; 95% confidence interval, 0.5-4.2 and hazard ratio, 1.7; 95% confidence interval, 0.5-5.6).

CONCLUSIONS

Patients with clinically manifest arterial disease or type 2 diabetes mellitus have a low risk of developing ischemic stroke, irrespective of its subtype and independent of the degree of ACAS stenosis.

Cilostazol prevents progression of asymptomatic carotid artery stenosis in patients with contralateral carotid artery stenting

BACKGROUND AND PURPOSE

The progression of atherosclerosis is related to various factors. Although antiplatelet therapy is used for the management of acute ischemic stroke and for the prevention of recurrent stroke, the antiplatelet agent cilostazol may also reduce restenosis after stent implantation in any vessel. This study was performed to assess the impact of cilostazol on plaque progression in the carotid artery contralateral to a stented artery.

MATERIALS AND METHODS

Ninety-five patients who underwent contralateral CAS who also had ipsilateral 0%-79% ICS were enrolled. ICS was assessed by duplex sonography every 6 months and by MR imaging/angiography, and digital subtraction angiography if necessary, every 12 months according to the NASCET method. Patient age, sex, past history, and perioperative medical conditions were recorded.

RESULTS

While 22.1% of patients experienced disease progression, symptomatic ipsilateral stroke occurred in only 1.1% of patients over 36.2 ± 18.8 months. On multivariate analysis, precarotid stenosis (HR per 10% increase, 2.08; 95% CI, 1.43-3.05; P < .001) and cilostazol use (HR 0.16; 95% CI, 0.03-0.85; P = .03) were independent predictors for the progression of ICS.

CONCLUSIONS

A higher degree of initial stenosis is associated with progression of asymptomatic ICS. Cilostazol may reduce the rate of disease progression in patients with asymptomatic ICS.

Carotid endarterectomy: still the standard of care for carotid bifurcation disease

Current treatment guidelines of symptomatic and asymptomatic carotid stenosis are based on studies performed over a decade ago. Since that time, significant advances have been made in medical management, namely high dose statin therapy and improved antiplatelet agents, and in carotid interventions, namely the advent of carotid artery stenting. Especially with carotid stenting, the technology has grown by leaps and bounds and continues to advance at a rapid pace. These advances have necessitated new studies to compare these treatments with the gold standard of carotid endarterectomy. In asymptomatic patients, the current data does not justify medical management alone for severe (>80%) carotid stenosis. Furthermore, in both asymptomatic and symptomatic patients current studies have failed to demonstrate equivalence of CAS to CEA for significant carotid stenosis. Clearly additional studies comparing CAS, CEA, and medical management are needed to further clarify this issue. In the future, advances in CAS technology and techniques may greatly expand the role of CAS beyond its current role in certain high-risk patient subsets. However, for the time being CEA still remains the gold standard for carotid intervention.

The value of a carotid duplex surveillance program for stroke prevention

BACKGROUND

Although duplex ultrasonography (DU) can readily identify progression of carotid stenosis, controversy regarding the natural history of asymptomatic carotid stenosis as well as the need and appropriate interval for carotid DU surveillance still exists. Furthermore, consensus has not yet been made in the surgical literature regarding the usefulness, cost-effectiveness, or timing of DU surveillance after carotid endarterectomy (CEA). The purpose of this study was to determine how often DU surveillance for asymptomatic carotid disease or postintervention stenosis resulted in any change in the patient's clinical management, how many strokes were prevented by DU surveillance, and the cost of such a DU surveillance program per stroke prevented.

METHODS

We reviewed a 9-year vascular surgical database to identify all patients enrolled in a carotid DU surveillance program for asymptomatic carotid stenosis or following CEA between January 1, 2000, and December 31, 2008. The number of duplex scans and CEAs performed in those patients through March 2010 was also determined. The results of the Asymptomatic Carotid Atherosclerosis Study were then used to estimate the number of strokes prevented by CEA in the study population. Reimbursement data were assessed to calculate the average cost of each DU and the cost of the DU surveillance program for each stroke prevented.

RESULTS

During the study period, there were 11,531 carotid duplex scans performed on 3,003 patients (mean: 3.84 scans per patient) who had been enrolled in the DU surveillance program. CEA for asymptomatic carotid stenosis was performed on 225 (7.5%) patients. The DU surveillance program prevented approximately 13 strokes (871 carotid duplex scans per stroke prevented). The mean cost of each duplex scan was $332 ± 170. The total cost of the DU surveillance program was approximately $3,830,000 or $290,000 per stroke prevented.

CONCLUSIONS

Although a carotid DU surveillance program generates substantial revenue for a vascular surgery practice, it is costly and inefficient. A reappraisal of the "value" of carotid DU surveillance in stroke prevention is warranted. Consideration should be given to eliminating routine surveillance of postendarterectomy carotids in the absence of contralateral disease and limiting the number of DU surveillance studies for asymptomatic carotid disease.

Clinical course of asymptomatic patients with carotid duplex scan end diastolic velocities of 100 to 124 centimeters per second

OBJECTIVE

With the decline of diagnostic angiography, clinicians increasingly rely upon duplex scan criteria to select appropriate asymptomatic candidates for carotid intervention. Some recent trials have enrolled patients for intervention based upon end diastolic velocities (EDVs) as low as 100 cm/second, and peak systolic velocities (PSVs) as low as 230 cm/second. In as much as we have used more selective duplex scan criteria, we reviewed the course of asymptomatic patients who had EDVs from 100 to 124 cm/second.

METHODS

Of the patients evaluated in our Intersocietal Commission for the Accreditation of Vascular Laboratories (ICAVL) accredited laboratory from 2002 to 2007, 144 patients had an EDV 100 to 124 cm/second. Of these, 47 patients underwent initial carotid intervention for concomitant symptoms (10), contralateral occlusion (3), or other imaging findings felt to warrant intervention. The remaining 97 asymptomatic patients were followed. One patient had both arteries fall within this EDV range. The mean follow-up for the 98 arteries was 29.1 months (range, 2-116 months).

RESULTS

Five patients (5.2%) developed ipsilateral symptoms consisting of one stroke and four transient ischemic attacks (TIAs), at a mean time of 35.3 months (range, 12-58 months). Twenty-six patients (26.8%), including 3 who also developed ipsilateral symptoms, progressed to having an EDV of ≥ 125 cm/second at a mean time of 24 months (range, 2-58). Two of these (2.1%) progressed directly to occlusion without symptoms and with no documented interim worsening of stenosis.

CONCLUSION

For asymptomatic individuals with an initial EDV of 100 to 124 cm/second, the risk of ipsilateral stroke is small and, therefore, medical management is appropriate in most cases. However, the risk of progression to a more severe degree of stenosis, often warranting carotid intervention, is clinically meaningful. Yearly duplex scan follow-up is necessary to assess disease progression in this patient cohort.

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.

Multidetector-row computed tomography in evaluation of atherosclerotic carotid plaques complicated with intraplaque hemorrhage

Our aim was to determine the sensitivity and specificity of multidetector-row computed tomography (CT) in detecting atherosclerotic carotid plaques complicated with intraplaque hemorrhage. We examined carotid plaques from 31 patients operated for carotid artery stenosis. Results of preoperative multidetector-row CT analysis of carotid plaques were compared with results of histological analysis of the same plaque areas. Carotid endarterectomy was performed within 1 week of multidetector-row CT. American Heart Association classification of atherosclerotic plaques was applied for histological classification. Median tissue density of carotid plaques complicated with intraplaque hemorrhage was 22 Hounsfield units (HU). Median tissue density of noncalcified segments of uncomplicated plaques was 59 HU (p=0.0062). The highest tissue density observed for complicated plaques was 31 HU. Multidetector-row CT detected plaques complicated with hemorrhage with sensitivity of 100% and specificity of 64.7%, with tissue density of 31 HU as a threshold value. Multidetector-row CT showed a high level of sensitivity and a moderate level of specificity in detecting atherosclerotic carotid plaques complicated with hemorrhage.

High-Sensitivity CRP Is Correlated With Neurologic Symptoms and Plaque Instability in Patients With Severe Stenosis of the Carotid Bifurcation

The aim of this study is to investigate the correlation of high-sensitivity C-reactive protein and E-selectin with clinical manifestations and plaque characteristics in 88 patients (69 with and 19 without neurological symptoms) with high-grade stenosis of the carotid bifurcation who underwent endarterectomy. The grade of stenosis was quantified by duplex ultrasonography and digital subtraction angiography. Preoperatively, serum high-sensitivity C-reactive protein and E-selectin were measured. Postoperatively, carotid plaque morphology was established according to the American Heart Association classification. High-sensitivity C-reactive protein levels were significantly ( P < .001) higher in symptomatic than in asymptomatic patients, as well as in patients with unstable compared with those with stable plaques ( P < .001). Serum high-sensitivity C-reactive protein levels correlated significantly ( P < .05) with macrophage count on the plaque. In conclusion, serum high-sensitivity C-reactive protein levels are associated with presence of neurological symptoms and plaque instability in patients with high-grade stenosis of the carotid bifurcation.

Asymptomatic Carotid Artery Stenosis and the Risk of New Vascular Events in Patients With Manifest Arterial Disease

Background and Purpose— The frequency of asymptomatic carotid artery stenosis (CAS) increases with age from 0.5% in individuals below 50 years of age to 5% to 10% in individuals over 65 years of age in the general population. Its prognostic value has been examined in the general population but less often in patients with clinical manifestations of arterial disease other than retinal or cerebral ischemia. We examined the relationship between asymptomatic CAS and the risk of subsequent events in this specific group of patients.

Methods— This study involved 2684 consecutive patients with clinical manifestations of arterial disease or type 2 diabetes mellitus, but without a history of cerebral ischemia, enrolled in the SMART study (Second Manifestations of ARTerial disease). The degree of asymptomatic CAS was assessed with Duplex scanning and defined on the basis of the blood flow velocity patterns at baseline in both carotid arteries. None of the patients underwent carotid endarterectomy or endovascular intervention. During the follow-up period, vascular events (vascular death, ischemic stroke, and myocardial infarction) were documented in detail. Data were analyzed with Cox proportional hazards regression and adjusted for age, gender, and classic vascular risk factors.

Results— Asymptomatic CAS of 50% or greater was present in 221 (8%) patients. During a mean follow up of 3.6 years (SD=2.3), a first vascular event occurred in 253 patients (9%). The cumulative incidence rate for the composite of subsequent vascular events after 5 years was 12.3% (95% CI=10.7 to 13.9), for cerebral infarction 2.2% (95% CI=1.4 to 2.8), and for myocardial infarction 8.0% (95% CI=6.6 to 9.4). Adjusted for age and gender, asymptomatic CAS of 50% or greater was related to a higher risk of subsequent vascular events (hazard ratio=1.5, 95% CI=1.1 to 2.1), in particular of vascular death (hazard ratio=1.8, 95% CI=1.2 to 2.6). After additional adjustment for vascular risk factors, the hazard ratios remained essentially the same.

Conclusion— Asymptomatic carotid artery stenosis is an independent predictor of vascular events, especially vascular death, in patients with clinical manifestations of arterial disease or type 2 diabetes but without a history of cerebral ischemia.

Progression of atherosclerosis in asymptomatic carotid arteries after contralateral endarterectomy: a 10-year prospective study

OBJECTIVE

The best way to manage both symptomatic and asymptomatic severe carotid stenoses has been thoroughly demonstrated by large randomized clinical trials, but less is known about the natural history and management of the contralateral asymptomatic internal carotid artery (ICA). This prospective study was undertaken to determine whether disease progressed in the contralateral ICA of patients who had undergone carotid endarterectomy (CEA) and were followed up clinically and by duplex ultrasound (US) scan.

METHODS

The contralateral asymptomatic ICAs of 599 patients who had undergone CEA for severe carotid disease over a 10-year period were followed up clinically and with duplex US scan at 1 month and then every 6 months. ICA stenosis was classified as mild (30%-49%), moderate (50%-69%), severe (70%-99%), or occlusion. Progression was defined as an increase in ICA stenosis of 50% or more for ICAs with a less than 50% baseline lesion or as an increase to a higher category if the baseline stenosis was 50% or more. End points of the study were the incidence of contralateral disease progression and late neurologic events. Kaplan-Meier analysis was used to estimate freedom from disease progression and from neurologic events. The relationship between progression and risk factors was also analyzed.

RESULTS

Overall, disease progressed in 25.2% of patients (151/599) after a mean follow-up of 4.1 years. Disease progressed in 34.3% of patients (101/294) with mild stenosis vs 47.9% of patients with moderate stenosis (47/98; P = .016). Three additional patients with mild lesions at baseline progressed to severe lesions. The median time to progression was 29.8 months for mild and 18.5 months for moderate stenoses (P = .033). The rate of late neurologic events referable to the contralateral ICA was 3.2% (19/599) for the entire series and 4.8% (19/392) for patients with a 30% or greater ICA stenosis: these included 4 (0.7%) strokes and 15 (2.5%) transient ischemic attacks. All but 3 events (16.3%; 16/98) occurred in patients with disease progression from moderate to severe stenosis. Overall, 53 late CEAs were performed.

CONCLUSIONS

This prospective analysis has shown that disease progression in contralateral asymptomatic ICAs after CEA is relatively common in patients with a diseased ICA at the baseline and strongly supports duplex US surveillance, approximately every 6 months, in patients with more than mild disease. A baseline lesion is significantly predictive of progression to severe stenosis, and progression from moderate to severe stenosis is strongly associated with neurologic clinical events. No demographic or clinical factor proved useful in identifying patients likely to experience disease progression.

Asymptomatic Carotid Artery Stenosis: Past, Present and Future

BACKGROUND

The role of carotid endarterectomy (CEA) for asymptomatic carotid artery stenosis (aCAS) remains a matter of debate. It seems that not only the degree of stenosis, but also other factors have to be taken in account to improve patient selection and increase the benefit of CEA for aCAS.

METHODS AND RESULTS

The literature pertaining aCAS was reviewed in order to describe the natural history, risk of stroke and benefit of CEA for patients with aCAS in regard to several factors.

CONCLUSION

The benefit of CEA for aCAS is low. Current factors influencing the indication for CEA are severity of stenosis, age, contralateral disease, stenosis progression to >80%, gender, concomitant operations and life expectancy. To improve patient selection investigations will concentrate on plaque characteristics and instability and cerebral hemodynamics and metabolism.

Cognitive functions in patients with cerebrovascular disease: potential impact of revascularization

The purpose of this review is to assess the impact of luminal restoring of carotid artery stenosis on cognitive functions. Therefore, papers dealing with the neuropsychological influence of carotid artery stenosis and studies comparing the neuropsychological course after respective recanalization have been included.

Disease Progression in the Contralateral Carotid Artery after Endarterectomy

Our objectives were to establish the incidence and progression of stenotic lesions in the contralateral carotid artery (CCA) after endarterectomy, to identify subpopulations of patients at risk of contralateral disease progression, and to evaluate the efficacy of duplex scanning surveillance at detecting these lesions. We performed a prospective study on 180 patients in whom the CCA to the operated artery was healthy or showed <70% stenosis. All patients had completed a clinical and hemodynamic follow-up program, including duplex scanning of both carotids, with sessions 3 and 6 months after surgery and then every semester until 2 years. Thereafter, examinations were scheduled according to the severity of stenosis. Mean follow-up time was 26.2 months (range 1.6-67.6). Disease progression was observed in 26 lesions (15%), nine of which (5.5%) progressed to severe stenosis (SS). Kaplan-Meier event-free rates of any disease progression were 89%, 88%, 82%, and 79% for 1, 2, 3, and 4 years, respectively. Event-free rates of progression to SS were 98%, 96%, 93%, and 90.6%, respectively, for 1, 2, 3, and 4 years. The risk of progression to SS was five times higher for stenoses that were moderate at the start of the study (p = 0.025). Severe contralateral stenoses were more common and appeared later during follow-up than ipsilateral restenoses. Progression of contralateral stenotic lesions is not uncommon and is essentially related to the presence of a moderate lesion at the start of follow-up. Indeed, moderate stenosis is a risk factor for progression to SS, which appears later and more frequently than ipsilateral restenosis. It therefore seems that patients with a moderate contralateral lesion would benefit from long-term duplex ultrasound surveillance.

Evaluation and management of asymptomatic carotid artery stenosis

Internal carotid artery stenosis (ICAS) is responsible for approximately 30% of ischemic strokes. Internal carotid artery stenosis of greater than 50% is present in about 4% to 8% of the population aged 50 to 79 years. Natural history studies and clinical trials have shown a small increase in stroke risk in patients with increasing degrees of ICAS, especially in those with greater than 80% reduction in carotid artery diameter. Randomized, prospective multicenter trials have revealed the superiority of carotid endarterectomy (CEA) over medical therapy in recently symptomatic patients with severe ICAS. However, the evidence from several randomized controlled trials of CEA in asymptomatic patients does not support the use of CEA in most of these patients; also, the role of noninvasive screening in this patient population remains uncertain and controversial. Furthermore, there is considerable uncertainty about whether the statistical benefit of avoiding a nondisabling stroke is worth the overall cost and risk of the procedure. Clinicians continue to struggle with treatment decisions for patients with asymptomatic ICAS. Carotid endarterectomy for asymptomatic ICAS should be considered only for medically stable patients with 80% or greater stenosis who are expected to live at least 5 years, and only in centers with surgeons who have a demonstrated low (<3%) perioperative complication rate. We outline the prevalence and natural history of ICAS, the evidence for CEA in patients with asymptomatic ICAS, the roles of screening and monitoring for ICAS, the methods of evaluating ICAS, and the implications for practicing clinicians.

Focused screening for occult carotid artery disease: patients with known heart disease are at high risk

OBJECTIVES

Stroke puts a major financial burden on our healthcare system. However, carotid duplex scanning performed as a screening test for occult carotid artery stenosis (CAS) currently is not reimbursed by Medicare. The goals of this study were to develop a cost-effective stroke screening program, to determine the prevalence of potential causes of stroke in this population, and to define a population at high risk in which screening would be most effective.

METHODS

In a community-based stroke screening program, patients were eligible if they were older than 60 years and had a history of either hypertension, heart disease, or cigarette smoking, or a family history of stroke. Screening included blood pressure determination, an electrocardiographic rhythm strip, and a previously validated modified carotid duplex ultrasound examination to detect CAS 50% or greater. The relationships between standard demographic risk factors and screening outcomes were analyzed.

RESULTS

Screening was performed in 610 patients. Unilateral or bilateral CAS was detected in 66 patients (10.8%). The finding of occult CAS was more prevalent than that of new hypertension (2.6%) or new atrial fibrillation (0.5%). Patients with known hypertension were significantly more likely to have CAS than were those without hypertension (12.7% vs 7.8%; P =.05). Patients with heart disease were significantly more likely to have CAS than were those without heart disease (18.2% vs 8%; P <.0001). Patients with both risk factors were significantly more likely to have occult carotid artery disease than were patients without either risk factor (22.1% vs 8.5%; P <.0001). Multivariate analysis with logistic regression revealed a history of heart disease as an independent predictor of occult carotid artery disease (odds ratio 95% confidence interval, 1.4-4.4). Type of heart disease was not a significant factor in predicting occult CAS. Direct cost of the screening, including community outreach, nurses, technicians, support staff, and miscellaneous expenses, was less than $75 per patient.

CONCLUSIONS

In a screening program for treatable causes of potential stroke, CAS was the most commonly diagnosed disease. More than one of every five patients with known hypertension and heart disease had occult CAS. Known heart disease of any type was a significant independent predictor of occult CAS. Screening for treatable causes of potential stroke can be cost-effective. This information could help to further target populations to screen for occult CAS and to justify reimbursement for screening carotid duplex scanning examinations.

Accelerated progression of carotid stenosis in patients with previous external neck irradiation

OBJECTIVE

Radiotherapy to the head and neck often results in carotid stenosis, but the course of disease is unknown. We investigated the natural history and progression of asymptomatic carotid stenosis induced by external irradiation. Patients and methods The study included 130 carotid arteries in 95 patients who had received external radiation therapy to the head and neck area and who had asymptomatic, mild internal carotid artery or common carotid artery stenosis. Stenosis of 15% to 49% on duplex ultrasound (US) scans defined mild (<50%) disease. Another 95 arteries in 74 patients with matched degree of carotid artery stenosis but who had not received radiation therapy were used as control. Both groups were followed up prospectively with serial duplex US scanning, and degree of carotid artery stenosis was categorized as 15% to 49%, 50% to 69%, 70% to 99%, and occlusion. Progression of carotid artery stenosis was defined as increase in stenosis from less than 50% to 50% or greater at ultrasonography. Secondary end points included progression to higher disease category, new cerebrovascular symptoms, and death. Data from irradiated arteries was compared with control data with the life table method. A Cox regression model was used to analyze disease progression, adjusted for covariates of sex, age, smoking, diabetes, and hypertension.

RESULTS

Mean follow-up was 36 months. Adjusted freedom from progression rates at 3 years were 65% for irradiated arteries and 87% for control arteries at life-table analysis (P =.035; odds ratio, 3.1). The annualized progression rate from less than 50% to 50% or greater in irradiated arteries was 15.4%, compared with 4.8% in nonirradiated arteries. A long history of cervical irradiation (>6 years) was the only significant risk factor for disease progression. There was no difference between the two groups regarding development of new symptoms or mortality.

CONCLUSIONS

Carotid stenosis associated with external irradiation progresses more rapidly compared with nonirradiated atherosclerotic arteries. Aggressive surveillance is recommended.

Natural history of carotid artery stenosis contralateral to endarterectomy: results from two randomized prospective trials

PURPOSE

A few nonrandomized studies have reported the natural history of carotid artery stenosis (CAS) contralateral to carotid endarterectomy (CEA). This study analyzed this condition with data from two randomized prospective trials.

METHODS

The contralateral carotid arteries in 534 patients from two randomized trials that compared CEA with primary closure versus patching were followed up clinically and with duplex ultrasound scanning at 1 month and then every 6 months. CAS was classified as less than 50%, 50% to 79%, 80% to 99%, and occlusion. Late contralateral CEA was performed to treat significant CAS. Progression was defined as progress to a higher category of stenosis. Kaplan-Meier life table analysis was used to estimate freedom from progression of CAS. The correlation of risk factors and CAS progression was also analyzed.

RESULTS

Of 534 patients, 61 had initial contralateral CEA and 53 had contralateral occlusion. Overall, CAS progressed in 109 of 420 patients (26%) at mean follow-up of 41 months. Progression of CAS was noted in 5 of 162 patients (3%) with baseline normal carotid arteries. CAS progressed in 56 of 157 patients (36%) with less than 50% stenosis versus 45 of 95 patients (47%) with 50% to 79% stenosis (P =.003). Median time to progression was 24 months for less than 50% CAS, and 12 months for 50% to 79% CAS (P =.035). At 1, 2, 3, 4, and 5 years, freedom from disease progression in patients with baseline CAS <50% was 95%, 78%, 69%, 61%, 48%, respectively, and in patients with 50% to 79% CAS was 75%, 61%, 51%, 43%, and 33%, respectively (P =.003). Freedom from progression in patients with baseline normal carotid arteries at 1 through 5 years was 99%, 98%, 96%, 96%, and 94%, respectively. Late neurologic events referable to the CCA were infrequent (28 of 420 [6.7%] in the entire series; 28 of 258 [10.9%] patients with contralateral CAS), and included 10 strokes (2.4%) and 18 transient ischemic attacks (4.3%). However, late contralateral CEA was performed in 62 patients (62 of 420 [15%] in the entire series; 62 of 258 [24%] patients with contralateral CAS). Survival rates were 96%, 92%, 90%, 87%, and 82%, respectively, at 1 through 5 years.

CONCLUSIONS

Progression of CCA stenosis was noted in a significant number of patients with baseline contralateral CAS. Serial clinical studies and duplex ultrasound scanning every 6 to 12 months in patients with 50% to 79% CAS, and every 12 to 24 months in patients with 50% or less CAS is adequate.

Natural history of > or =60% asymptomatic carotid stenosis in patients with contralateral carotid occlusion

OBJECTIVE

Although the Asymptomatic Carotid Atherosclerosis Study (ACAS) reported that carotid endarterectomy (CEA) is beneficial for patients with asymptomatic > or =60% carotid stenosis (ACS), several other studies have reported mixed results. Our prospective study analyzed the natural history of > or =60% ACS in patients with contralateral carotid occlusion (CCO).

PATIENT POPULATION AND METHODS

During a 10-year period, patients with 60-<70% ACS with CCO were entered into a protocol of clinical examination and duplex surveillance every 6 months. All patients underwent maximum medical therapy. Late CEAs were considered if lesions became symptomatic or progressed to > or =70% stenosis. A Kaplan-Meier lifetable analysis was performed to estimate the freedom from both ipsilateral strokes and all strokes.

RESULTS

Eighty-two patients were enrolled with a mean follow-up of 59.5 months (range, 7-141 months). Late strokes were noted in 27 of 82 patients (33%); 19 (23%) were ipsilateral and 8 (10%) were contralateral (side of CCO). Late transient ischemic attacks (TIAs) were noted in 22 of 82 (27%, 7 ipsilateral and 15 contralateral). The combined neurologic event (TIA/stroke) rate was 60% (49 of 82, 32% ipsilateral and 28% contralateral). Kaplan-Meier lifetable analysis showed that the rates of freedom from ipsilateral strokes, all strokes, and progression to > or =70% stenosis at 1, 2, 3, 4, and 5 years were 94%, 90%, 85%, 80%, 73%; 94%, 89%, 84%, 77%, 67%; and 99%, 96%, 92%, 86%, and 82%, respectively. The ipsilateral stroke-free survival rates at l, 2, 3, 4, and 5 years were 94%, 88%, 78%, 70%, and 63%. Twenty-one late CEAs were performed with no perioperative stroke/deaths (5 for ipsilateral TIAs, 9 for ipsilateral strokes, and 7 for > or =70% ACS). Overall, 20 (24%, 11 with symptoms and 9 asymptomatic) progressed to > or =70% stenosis.

CONCLUSIONS

Patients with 60-<70% ACS and CCO with maximal medical therapy carry a higher incidence of ipsilateral strokes and all strokes than what was reported by the ACAS study; therefore, prophylactic CEA may be justified in these patients.

Multiple modifiable risk factors for first ischemic stroke: a population-based epidemiological study

The aims of this epidemiological population-based cohort study were to examine the prevalence of the multiple modifiable vascular risk factors, their distribution patterns and outcomes among a Bulgarian urban population. A total of 500 volunteers, 200 men and 300 women, without clinical signs and symptoms of cerebrovascular disease, aged 50-79 years, were enrolled in the study. A structured questionnaire, physical examination, electrocardiogram records, a battery of laboratory tests and carotid duplex scanning were employed. Three or more modifiable vascular risk factors were detected in 52% (260/500) of the subjects. Dyslipidemias, hypertension, obesity, cigarette smoking and cardiac diseases were found to be the most prevalent single risk factors. Asymptomatic carotid stenosis (ACS) of 50% or greater was detected in 8.8% (23/260) of the volunteers examined. After a 2-year follow-up, 2.7% (7/260) of the persons with modifiable vascular risk factors reached the end point transient ischemic attacks (TIAs), ischemic stroke and myocardial infarction. The following combinations of risk factors among the subjects enrolled in the study were significantly associated with these outcomes: hypertension and cardiac diseases (OR = 6.82; 95% CI, 1.21-38.41), cardiac diseases and obesity (OR = 6.13; 95% CI, 1.27-29.72), ACS and high low-density lipoprotein (LDL) cholesterol levels (OR = 11.11; 95% CI, 1.58-78.29). The identification of subjects with multiple vascular risk factors may be important for primary medical or surgical stroke prevention.

Evolving atherosclerosis at carotid and intracranial arteries in Japanese patients with ischemic heart disease: a 5-year longitudinal study with MR angiography

Progression of atherosclerosis at extracranial carotid and intracranial arteries in patients with ischemic heart disease (IHD) is not well defined. We carried out a 5-year longitudinal study with magnetic resonance angiography (MRA) of patients with IHD to assess the incidence of progression of atherosclerosis at extracranial carotid and intracranial arteries and to determine predictors of the progression. We previously performed carotid and intracranial MRA on 67 patients who had received selective coronary angiography for the clinical diagnosis of IHD. Of these 67 subjects, 41 patients gave informed consent to undergo MRA reexaminations to evaluate changes of extra- and intracranial arteries over a 5-year period. The degree of stenosis was divided into five grades depending on the narrowness of the arteries, i.e. normal, mild, moderate, severe and occluded. The average of follow-up period with MRA examination was 58.8 months. The progression of atherosclerosis, as defined as an increase of one grade of the stenosis rating, including both the exacerbation of pre-existing stenosis and the appearance of new stenotic lesions, were found in five patients (12.2%) for the cervical carotid artery and in only one patient (2.4%) for the intracranial artery. A multiple logistic regression analysis revealed that baseline carotid artery stenosis (P = 0.008), age (P = 0.047), and coronary events during the follow-up period (P = 0.048) were significant and independent predictors of progression of carotid atherosclerosis. In conclusion, our findings suggest that follow-up evaluation of the carotid artery is indicated for patients with IHD in whom carotid artery stenosis was detected on an initial examination. Further study is needed with larger numbers of patients to confirm these findings.

Cerebral haemodynamic aspects of severe carotid stenosis: asymptomatic vs symptomatic

OBJECTIVES

to compare cerebral haemodynamics in patients with asymptomatic and symptomatic severe (> or =70%) internal carotid artery (ICA) stenosis.

METHODS

we assessed 195 consecutive patients, 116 with asymptomatic carotid stenosis (ACS) and 79 with symptomatic carotid stenosis (SCS). Using transcranial Doppler we assessed cerebral vasoreactivity (CVR) following acetazolamide test, the middle cerebral artery flow velocity ratio after/before carotid clamping (mv-MCA ratio), and the carotid back pressure (CBP) during crossclamping.

RESULTS

no significant differences between the two groups were demonstrated regarding CVR (47 vs 39%), mv-MCA ratio (50 vs 52%), or CBP (36 vs 44 mmHg). However, in patients with contralateral ICA occlusion all three variables were significantly lower as compared to patients with patent contralateral ICA. Also patients who needed a shunt during surgery had significantly lower values of mv-MCA ratio and CBP. Patients who suffered peri-operative neurologic deficits (n=6; 3%) did not differ from patients who had an uneventful course.

CONCLUSIONS

clinical state of ICA stenosis is independent of cerebral haemodynamics. Occluded contralateral ICA is more important for predicting cerebral ischaemia caused by carotid clamping. Finally, none of the haemodynamic parameters showed predictive value for peri-operative neurologic morbidity.

Prevalence and outcome of asymptomatic carotid stenosis: a population-based ultrasonographic study

The aims of this epidemiological population-based cohort study were to examine the prevalence and outcomes of asymptomatic carotid stenosis (ACS) detected by duplex scanning and its relations to other vascular risk factors. A total of 500 volunteers, 200 men and 300 women, without signs and symptoms of cerebrovascular disease, aged 50-79 years, were enrolled in the study. The prevalence of ACS of 50% or greater was 6.4%. Only severe carotid stenosis was detected in 0.4% of the subjects examined. Significant relationships between ACS and coronary heart disease (CHD) [odds ratio (OR)=8.00], peripheral arterial disease (PAD) (OR=3.66), cigarette smoking in men (OR=4.39) and obesity in women (OR=0.31) were found. The biennial incidence rate of cerebral ischaemic events was 9.4%. A progression of ACS was revealed in 14% and a regression in 6.25% of the subjects. The patients with progressing ACS to more than 70% diameter reduction reached the end-points. Follow-up with repeated duplex scans in patients with advancing ACS of 50% or greater, especially smokers with CHD and PAD, is recommended.

Carotid stenosis: factors affecting symptomatology

BACKGROUND AND PURPOSE

The ability to predict future strokes in asymptomatic patients with carotid stenosis is currently limited. The management of symptomatic patients with <50% stenosis is also debatable. In this context, we performed the following open prospective study to identify factors affecting symptomatology in patients with carotid stenosis.

METHODS

During 1988-1997, 442 arteries with various degrees of stenosis were followed with the use of color Duplex ultrasonography every 6 months. The main outcome measures were development of symptoms related to the carotid territory and progression in the degree of stenosis. Results of follow-up were analyzed in relation to the traditional risk factors for atherosclerosis as well as the ultrasonographic characteristics of the plaques. Statistical analysis was performed by multiple linear and Cox regression analysis.

RESULTS

Mean duration of follow-up was 44 months (range, 12 to 120 months). Significant progression of stenosis occurred in 18.5% of the cases and was more frequent in younger patients (P=0.09), in patients with coronary artery disease (P=0.02), and in patients with echolucent plaques (P=0.02). In regard to clinical presentation, men (P=0.07), hypertensives (P=0.07), and patients with echolucent plaques (P=0.09) showed a trend toward higher frequency of stroke in their history. During the follow-up period, neurological events developed in 12.4% of the cases and were associated with the severity of carotid disease (P<0.001), history of neurological events (P=0.02), progression of stenosis (P=0.002), echolucent plaques (P=0.01), and hypertension (P=0.02).

CONCLUSIONS

Factors other than degree of stenosis and history of neurological events are also important in determining high-risk carotid plaque. In our study hypertension, echolucent plaques, and progressive lesions were associated with an increased risk of neurological events. These factors should be taken into consideration in determining treatment strategies for carotid stenosis.

Optimizing duplex follow-up in patients with an asymptomatic internal carotid artery stenosis of less than 60%

OBJECTIVES

The Asymptomatic Carotid Atherosclerosis Study established benefit of carotid endarterectomy for 60% to 99% asymptomatic internal carotid artery (ICA) stenosis. Optimal follow-up intervals to detect progression from < 60% to 60%-99% ICA stenosis are unknown. In a previous study from our laboratory, we found that ICAs with < 60% stenosis and peak systolic velocities (PSVs) of 175 cm/s or more on initial duplex were at high risk for progression. Prospective evaluation of this hypothesis and determination of optimal duplex follow-up intervals for asymptomatic patients with < 60% ICA stenosis form the basis of this report.

METHODS

All patients who underwent initial carotid duplex examination for any indication since January 1, 1995, with at least one patent, asymptomatic, previously nonoperated ICA with < 60% stenosis; with 6 months' or greater follow-up; and with one or more repeat duplex examinations were entered into the study. On the basis of the initial duplex examination, ICAs were classified into two groups: those with a PSV less than 175 cm/s and those with a PSV of 175 cm/s or more. Follow-up duplex examinations were performed at varying intervals to detect progression from < 60% to 60%-99% ICA stenosis with criteria previously reported (both PSV > or = 260 cm/s and end-diastolic velocity > or = 70 cm/s).

RESULTS

A total of 407 patients (640 asymptomatic ICAs with < 60% stenosis) underwent serial duplex scans (mean follow-up, 22 months). Three ICAs (0.5%) became symptomatic and progressed to 60%-99% ICA stenosis at a mean of 21 months (all transient ischemic attacks), whereas four other ICAs occluded without stroke during follow-up. Progression to 60%-99% stenosis without symptoms was detected in 46 ICAs (7%) (mean, 18 months). Of the 633 patent asymptomatic arteries, 548 ICAs (87%) had initial PSVs less than 175 cm/s, and 85 ICAs (13%) had initial PSVs of 175 cm/s or more. Asymptomatic progression to 60%-99% ICA stenosis occurred in 22 (26%) of 85 ICAs with initial PSVs of 175 cm/s or more, whereas 24 (4%) of 548 ICAs with initial PSVs less than 175 cm/s progressed (P <.0001). The Kaplan-Meier method was used to determine freedom from progression at 6 months, 12 months, and 24 months, which was 95%, 83%, and 70% for ICAs with initial PSVs of 175 cm/s or more versus 100%, 99%, and 95%, respectively, for ICAs with initial PSVs less than 175 cm/s (P <.0001).

CONCLUSIONS

Patients with < 60% ICA stenosis and PSVs of 175 cm/s or more on initial duplex examination are significantly more likely to progress asymptomatically to 60%-99% ICA stenosis, and progression is sufficiently frequent to warrant follow-up duplex studies at 6-month intervals. Patients with < 60% ICA stenosis and initial PSVs less than 175 cm/s may have follow-up duplex examinations safely deferred for 2 years.

Carotid Endarterectomy for Severe Asymptomatic Carotid Stenosis: A Perioperative Experience at a Community Hospital

The purpose of this study was to evaluate the safety and feasibility of carotid endarterectomy (CEA) for severe asymptomatic carotid stenosis in a community setting with direct surgical resident participation. The medical records of all patients who had undergone CEA for severe asymptomatic carotid stenosis between 1989 and 1997 were retrospectively reviewed to ascertain perioperative morbidity and mortality. One hundred forty-seven CEAs were performed on 131 patients over the 8-year interval. Perioperative stroke and death rate was 0 per cent. However, one patient had a postoperative transient ischemic attack, and one patient had vocal cord dysfunction due to vagus nerve injury (1.3%). Three other patients had perioperative complications not directly related to CEA (2.1%). Therefore the total perioperative complication rate of (3.4%) compares favorably with results reported by several large tertiary referral centers. CEA for severe asymptomatic carotid stenosis can be safely performed in a community hospital setting with direct surgical resident participation.

Carotid atherosclerosis, vascular risk profile and mortality in a population-based sample of functionally healthy elderly subjects: the Berlin ageing study

OBJECTIVES

Studies on extracranial carotid atherosclerosis have predominately been undertaken on middle-aged subjects. This study examines the prevalence of extracranial carotid atherosclerosis, its relation to vascular risk factors and its significance for survival in elderly subjects.

DESIGN

Population-based cross-sectional survey. Non-modifiable vascular risk factors examined were family history of atherosclerotic disease, sex and apolipoprotein E (apoE) genotype. Potentially modifiable risk factors assessed were smoking, fibrinogen, fasting lipids, body mass index, hypertension and diabetes.

SETTING AND SUBJECTS

Two hundred and twenty-five functionally healthy volunteers of the Berlin Ageing Study, aged 70-100.

MAIN OUTCOME MEASURES

Presence of carotid stenosis and plaque ascertained by ultrasound imaging; 5-year mortality.

RESULTS

At least one plaque was found in 144 (64%) of the volunteers; 34 (15%) had a stenosis over 50%; and nine (4%) had a stenosis over 75%. Total cholesterol > 6.5 mmol L-1, LDL cholesterol > 4.6 mmol L-1 and total cholesterol/HDL cholesterol ratio > 5 were significantly associated with presence of plaque in 70- to 80-year-old subjects, as was diabetes in subjects over 80 years. Log-linear analyses showed significant three-way interactions for high LDL cholesterol and diabetes with plaques and age. Family history, sex, apoE genotype, smoking and fibrinogen were not related to presence of plaque in the study population. Cox regression analysis revealed increased 5-year mortality rates for subjects with plaques (OR = 2. 88; 95% CI = 1.30-6.35), whereas the vascular risk profile was not associated with mortality.

CONCLUSIONS

In a population-based sample of functionally healthy elderly subjects, the significance of the vascular risk profile seemed to be diminished. It had no impact on survival and only modifiable risk factors showed an age-dependent association with carotid disease.

Internal carotid artery stenosis: rate of progression

OBJECTIVES

to assess the incidence and the rate of progression of internal carotid artery (ICA) stenosis and to determine the related risk factors.

DESIGN

open prospective study.

MATERIALS AND METHODS

between 1988-1997, 442 carotid arteries with various degrees of stenosis were followed using colour duplex ultrasonography every 6 months. Of these arteries, 290 (66%) were asymptomatic, 62 (14%) had caused transient ischaemic attack and 90 (20%) a stroke. In 145 cases (33%), there was concomitant coronary artery disease (CAD), in 134 (30%) diabetes mellitus, in 248 (56%) hypertension, in 139 (31%) hypercholesterolaemia and in 370 (84%) history of smoking. Of the plaques, 44 (10%) were uniformly echolucent, 19 (4%) haemorrhagic, 136 (31%) predominantly echolucent, 146 (33%) predominantly echogenic and 97 (22%) uniformly echogenic.

RESULTS

significant progression of stenosis occurred in 82 cases (19%). The mean progression rate in these cases was 15% annually (range: 5-50%). There was no statistically significant correlation between the progression of the ICA stenosis and initial neurological status, age, gender, diabetes mellitus, hypertension, hypercholesterolaemia and smoking habit. Stenosis progression was correlated only with CAD and the ultrasonographic characteristics of the plaques. Patients with CAD as well as those with uniformly echolucent plaques presented a higher incidence and rate of stenosis progression (p<0.05).

CONCLUSIONS

progression of internal carotid artery stenosis occurred in 19% of cases. The mean progression rate in these patients was 15% annually and was correlated with CAD and the ultrasonographic characteristics of the plaque.