Correlation of bruits over the carotid artery with angiographically demonstrated lesions

Detection of Disease at the Carotid Bifurcation Using Ultrasound – Including an Imaging System1

A two-stage approach is described for the detection of occlusive arterial disease at the carotid bifurcation using continuous wave Doppler-shift ultrasound with spectral analysis of backscattered signals from erythrocytes. The first stage involves analysis of Doppler-shift signals from the supraorbital and common carotid arteries. Abnormal signals from these arteries are frequently caused by the presence of atheroma at the carotid bifurcation and are used to indicate the necessity for imaging the bifurcation. This latter technique produces a physiological image of the arteries, as it depends on detecting erythrocyte velocities beneath a transducer which is guided over the surface of the neck. The investigation has advantages over arteriography in that it is noninvasive, has no attendant risk and may be repeated as often as required.

In order to evaluate the accuracy of these methods the results have been compared with x-ray findings in patients undergoing carotid arteriography. In 20 comparisons there were no false positives and one false negative in which the arteriogram showed a small lesion. These results indicate that the two noninvasive methods may be used in sequence to demonstrate operable disease around the carotid junction.

Evaluation of the clinical utility of a carotid bruit

BACKGROUND

Uncertainty exists over whether listening for carotid bruits as part of the clinical examination is informative in terms of predicting the presence or severity of carotid stenosis.

AIM

We sought to undertake a comprehensive meta-analysis and meta-regression of all studies to date that have assessed the relationship between a carotid bruit and severity of degree of stenosis.

METHODS

Electronic databases were used to identify all published studies in humans evaluating the association between bruit and stenosis published until and including October 2011. Pooled sensitivity, specificity and diagnostic odds ratio (DOR) were calculated for each stenosis group. Summary receiver operating characteristic (SROC) curve analysis was performed in studies assessing clinically relevant (i.e. >70%) stenosis. Meta-regression was performed in all studies, using random effects.

RESULTS

We identified 26 studies evaluating the association between carotid bruit and stenosis, in 15 117 arteries. For clinically relevant stenosis (i.e. >70%), we found pooled sensitivity 0.53 [95% confidence interval (CI): 0.5-0.55], specificity 0.83 (95% CI: 0.82-0.84) and DOR 4.32 (95% CI: 2.78-6.66). SROC curve analysis gave an area under the curve of 0.73. Meta-regression analysis showed a (non-significant) (P = 0.067) inverse relationship between carotid bruit and stenosis.

CONCLUSION

The carotid bruit is of moderate value for detecting clinically relevant carotid stenosis. It gives high specificity but low sensitivity. The likelihood of a carotid bruit does not increase at increasing degrees of stenosis.

Guidelines for the primary prevention of stroke: a guideline for healthcare professionals from the American Heart Association/American Stroke Association

BACKGROUND AND PURPOSE

This guideline provides an overview of the evidence on established and emerging risk factors for stroke to provide evidence-based recommendations for the reduction of risk of a first stroke.

METHODS

Writing group members were nominated by the committee chair on the basis of their previous work in relevant topic areas and were approved by the American Heart Association (AHA) Stroke Council Scientific Statement Oversight Committee and the AHA Manuscript Oversight Committee. The writing group used systematic literature reviews (covering the time since the last review was published in 2006 up to April 2009), reference to previously published guidelines, personal files, and expert opinion to summarize existing evidence, indicate gaps in current knowledge, and when appropriate, formulate recommendations using standard AHA criteria (Tables 1 and 2). All members of the writing group had the opportunity to comment on the recommendations and approved the final version of this document. The guideline underwent extensive peer review by the Stroke Council leadership and the AHA scientific statements oversight committees before consideration and approval by the AHA Science Advisory and Coordinating Committee.

RESULTS

Schemes for assessing a person's risk of a first stroke were evaluated. Risk factors or risk markers for a first stroke were classified according to potential for modification (nonmodifiable, modifiable, or potentially modifiable) and strength of evidence (well documented or less well documented). Nonmodifiable risk factors include age, sex, low birth weight, race/ethnicity, and genetic predisposition. Well-documented and modifiable risk factors include hypertension, exposure to cigarette smoke, diabetes, atrial fibrillation and certain other cardiac conditions, dyslipidemia, carotid artery stenosis, sickle cell disease, postmenopausal hormone therapy, poor diet, physical inactivity, and obesity and body fat distribution. Less well-documented or potentially modifiable risk factors include the metabolic syndrome, excessive alcohol consumption, drug abuse, use of oral contraceptives, sleep-disordered breathing, migraine, hyperhomocysteinemia, elevated lipoprotein(a), hypercoagulability, inflammation, and infection. Data on the use of aspirin for primary stroke prevention are reviewed.

CONCLUSIONS

Extensive evidence identifies a variety of specific factors that increase the risk of a first stroke and that provide strategies for reducing that risk.

Carotid bruit for detection of hemodynamically significant carotid stenosis: the Northern Manhattan Study

OBJECTIVE

The prevalence of carotid bruits and the utility of auscultation for predicting carotid stenosis are not well known. We aimed to establish the prevalence of carotid bruits and the diagnostic accuracy of auscultation for detection of hemodynamically significant carotid stenosis, using carotid duplex as the gold standard.

METHODS

The Northern Manhattan Study (NOMAS) is a prospective multiethnic community-based cohort designed to examine the incidence of stroke and other vascular events and the association between various vascular risk factors and subclinical atherosclerosis. Of the stroke-free cohort (n=3298), 686 were examined for carotid bruits and underwent carotid duplex. Main outcome measures included prevalence of carotid bruits and sensitivity, specificity, positive predictive value, negative predictive value and accuracy of auscultation for prediction of ipsilateral carotid stenosis.

RESULTS

Among 686 subjects with a mean age of 68.2 +/- 9.4 years, the prevalence of >/=60% carotid stenosis as detected by ultrasound was 2.2% and the prevalence of carotid bruits was 4.1%. For detection of carotid stenosis, sensitivity of auscultation was 56%, specificity was 98%, positive predictive value was 25%, negative predictive value was 99% and overall accuracy was 97.5%.

DISCUSSION

In this ethnically diverse cohort, the prevalence of carotid bruits and hemodynamically significant carotid stenosis was low. Sensitivity and positive predictive value were also low, and the 44% false-negative rate suggests that auscultation is not sufficient to exclude carotid stenosis. While the presence of a bruit may still warrant further evaluation with carotid duplex, ultrasonography may be considered in high-risk asymptomatic patients, irrespective of findings on auscultation.

Predictive value of asymptomatic cervical bruit for carotid artery disease in coronary artery surgery revisited

OBJECTIVE

To investigate the predictive value of asymptomatic cervical bruit for detecting internal carotid artery disease in consecutive patients undergoing coronary artery bypass grafting (CABG).

DESIGN

A prospective cohort study.

SETTING

Tertiary referral university hospitals.

PATIENTS

153 consecutive patients (mean age 57 years) undergoing CABG, without previous history of cerebrovascular events.

INTERVENTIONS

Patients underwent detailed pre-operative work-up, including coronary angiography and carotid artery duplex scanning. Internal carotid artery diameter stenosis was graded as A: normal; B: < 15%; C: 15%-50%; D: 50-80%; D+: > 80-99% and E=complete occlusion.

RESULTS

72 patients (47.1%) (95% CI: 39%, 55%) had no evidence of internal carotid artery stenosis; 81 (52.9%) (95% CI: 44.9%, 60.9%) had varying grades of disease, unilateral or bilateral. Cervical bruit was detected in 12/153 patients (7.8%) (95% CI: 3.5%, 12.1%) of whom all but one (0.7%) had varying grades of internal carotid artery disease; of these, 4 patients had bilateral cervical bruit (2.6%) (95% CI: 0.06%, 5.2%). The sensitivity, specificity, positive and negative predictive values and overall accuracy of cervical bruit for detection of > or = 50% internal carotid artery stenosis were 23.5%, 95.8%, 25%, 95.5% and 91.8%, respectively. The relative risk of > or = 50% stenosis ipsilateral to cervical bruit in 306 sides was 5.58 (95% CI: 2.0, 15.0) and the odds ratio 7.1 (95% CI: 2.0, 25.0).

CONCLUSIONS

Asymptomatic cervical bruit proved a highly specific clinical sign for detection of internal carotid artery stenosis, whether haemodynamically significant (> or = 50%) or otherwise, in patients undergoing myocardial revascularisation. This was matched by a high negative predictive value and overall accuracy for flow limiting atheroma (> or = 50% stenosis). Yet, steering carotid investigations on the basis of cervical bruit alone would result in > or = 80% internal carotid artery stenosis remaining undetected in 3% of overall patients, in whom cervical bruit is absent.

Prospective evaluation of carotid bruit as a predictor of first stroke in type 2 diabetes: the Fremantle Diabetes Study

BACKGROUND AND PURPOSE

We sought to examine prospectively the relationship between asymptomatic carotid bruit and stroke in type 2 diabetes.

METHODS

We studied 1181 (91.3%) of a community-based sample of 1294 patients with type 2 diabetes. These patients had no history of cerebrovascular disease at recruitment during 1993-1996 and were followed until the end of January 2002. Hospital morbidity and death register data relating to cerebrovascular events were also available. Cox proportional hazards models were used to determine whether carotid bruit status was an independent predictor of stroke and to identify other significant cerebrovascular risk factors.

RESULTS

One hundred thirty-four patients (11.3%) suffered a first stroke during 6.5+/-2.2 (mean+/-SD) years of follow-up. In the first 2 years after study entry, first stroke (n=45/1181; 3.8%) was strongly predicted by the presence of carotid bruit(s) after adjustment for known cardiovascular risk factors and other potentially confounding variables (hazard ratio, 6.7; 95% CI, 3.0 to 14.9; P<0.001). Between 2 years and census, first stroke (n=89/1083; 8.2%) was not associated with carotid bruit(s) (P=0.97). Age and diastolic blood pressure were other determinants of stroke in the first 2 years, while age, atrial fibrillation/flutter, and microalbuminuria were independent predictors of subsequent stroke.

CONCLUSIONS

Type 2 diabetic patients found to have incidental carotid bruits have >6 times the risk of first stroke in the first 2 years than patients without a bruit and should receive intensified management of vascular risk factors. Carotid imaging with a view to surgical intervention in these patients remains controversial.

The utility of preoperative routine carotid artery duplex scanning in patients undergoing aortic valve replacement

Patients with aortic valve disease (AVD) typically have a cardiac murmur that radiates to the neck and may be indistinguishable from a cervical bruit secondary to carotid artery occlusive disease. The purpose of this report was to determine the prevalence of significant asymptomatic carotid artery occlusive disease in patients undergoing aortic valve replacement (AVR). All patients scheduled for AVR were prospectively studied. Preoperative carotid artery color-flow duplex was performed in all patients. A total of 204 patients were included in the study and significant carotid disease (>50% stenosis of the internal carotid artery) was found in 17 (8%). In patients with isolated aortic valve disease, 4/129 (3%) had significant stenosis. Of the patients with concurrent aortic valve and coronary artery disease, 13/75 (17%) had significant stenosis. The incidence of significant carotid stenosis in patients with aortic valve disease was over five fold higher in patients with concurrent coronary artery disease (3% vs. 17%, p <0.001). The yield of routine carotid duplex scanning for patients undergoing isolated AVR is low. However, in the subset of patients with concurrent coronary disease, the yield is higher. This finding supports the use of routine carotid duplex scanning in patients with coexistent aortic valve and coronary artery disease.

Carotid screening with duplex ultrasound in elderly asymptomatic patients referred to a vascular surgeon: is it worthwhile?

The purpose of this study is to prospectively determine the outcome of carotid duplex ultrasound screening in patients referred to a vascular surgeon for problems other than carotid disease. During a recent 12-month period, 307 patients age 65 years and older (mean 76 +/- 8 years) were referred to one vascular surgeon for problems other than cerebrovascular disease. Fifty-one percent of the patients were male, 49% were female, 32% were diabetic, 32% were hypertensive, 31% smoked, 20% had coronary artery disease, and 64% had peripheral arterial occlusive disease. All patients underwent a screening duplex ultrasound exam of the carotid arteries as approved by our Institutional Review Board. The results of our study showed that the prevalence of asymptomatic carotid artery stenosis >70% among patients seen by a vascular surgeon for problems other than cerebrovascular disease is high (21%) and is associated with male gender, advanced age, diabetes mellitus and having quit smoking. Continued carotid artery duplex screening is warranted in this patient population greater than age 65 years.

Advances in Management of Carotid Atherosclerosis

Carotid artery stenosis is a common and potentially treatable cause of stroke. Stroke risk is increased as the degree of carotid stenosis increases, as well as in patients with neurological symptoms referable to the stenosed carotid artery. Carotid stenosis can be quantified by ultrasound imaging, magnetic resonance angiography, or conventional angiography. Medical treatment with platelet antiaggregants reduces stroke risk in some patients; other patients are best treated with carotid endarterectomy. Experimental treatments for carotid stenosis, including carotid angioplasty with or without stenting, are under investigation. We summarize the current literature and provide treatment recommendations for patients with atherosclerotic carotid artery disease.

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

BACKGROUND AND PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND AND PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Predictive value of bruits and Doppler pressure measurements in detecting lower limb arterial stenosis

The value of bruits and Doppler ankle pressure measurements as indicators of arterial stenosis was studied in 50 patients with symptoms of lower limb ischaemia. The iliac and femoropopliteal arteries were examined for bruits, ankle systolic pressures were measured before and after an exercise stress test and the results were compared to the findings of digital subtraction angiography (DSA). Patients with occlusive lesions in the iliac and femoropopliteal arteries were not analysed. This left a group of 37 symptomatic legs in which the popliteal pulse was palpable. In this sub-group, DSA demonstrated 25 limbs with arterial stenoses and 12 limbs without evidence of a stenosis. The presence of a bruit had a sensitivity of 80%, a specificity of 75%, a positive predictive value of 87%, a negative predictive value of 64% and an accuracy of 78%. A fall in Doppler ankle pressure of > or = 20 mmHg had a sensitivity of 92%, a specificity of 75%, a positive predictive value of 88%, a negative predictive value of 82% and an accuracy of 86%. When used selectively, clinical examination for bruits has good accuracy and may be of clinical value in the early identification of patients who are suitable for percutaneous transluminal angioplasty.

Improved prognosis for asymptomatic carotid stenosis with prophylactic carotid endarterectomy

BACKGROUND AND PURPOSE

The value of carotid endarterectomy in asymptomatic patients with high-grade stenosis is controversial. The objective of this study is to compare the immediate and long-term outcome of patients after carotid endarterectomy for asymptomatic carotid stenosis (greater than 75%) with the reported natural history of patients followed nonoperatively to determine whether carotid endarterectomy reduces the subsequent neurological event rate.

METHODS

The data from 141 carotid endarterectomies performed in 123 patients between January 1980 and December 1986 were reviewed from the perspective of perioperative results and long-term follow-up to January 1990, providing a follow-up ranging from 3 to 10 years. The mean follow-up was 56.6 months (range 27-117 months).

RESULTS

There were no perioperative deaths. There were two postoperative stokes: one in the cerebellar distribution and one in the middle cerebral distribution. During the course of follow-up, no patient suffered a stroke in the hemisphere ipsilateral to carotid endarterectomy. One patient developed ipsilateral transient ischemic attacks 24 months after surgery associated with carotid restenosis. A total of three patients developed four recurrent carotid stenoses, for an incidence of 2.8%. All four recurrences were corrected surgically.

CONCLUSIONS

These findings are in marked contrast to the reported natural history of patients with greater than 75% stenosis in which the 1-year neurological event rate is 18% and the 1-year stroke rate is 5%. Although final proof of efficacy for prophylactic carotid endarterectomy in asymptomatic patients will await the outcome of randomized trials, until these data are available, prophylactic carotid endarterectomy is justified in centers of excellence that can perform the surgery with low perioperative risk.

Symptomatic carotid ischaemic events: safest and most cost effective way of selecting patients for angiography, before carotid endarterectomy

OBJECTIVE

To determine the safest, least costly, and most effective way to select patients with symptomatic carotid ischaemic events for carotid angiography before carotid endarterectomy.

DESIGN

Prospective cohort study.

SETTING

University departments of clinical neurosciences and clinical neurology.

PATIENTS

485 Patients with carotid territory transient ischaemic attacks of the brain (n = 224) or eye (n = 162) or retinal infarction (n = 99) were referred to a single neurologist between 1976 and 1986.

INTERVENTIONS

Clinical examination by auscultation over the precordium, supraclavicular fossae, and neck vessels (all patients). Cerebral angiography of patients suitable for carotid endarterectomy.

MAIN OUTCOME MEASURES

Financial cost and number of disabling strokes after angiography.

RESULTS

296 Patients were investigated by cerebral angiography. Ischaemic symptoms had occurred in the distribution of 298 internal carotid arteries (symptomatic) that were imaged, two patients having bilateral symptoms. The presence or absence of a carotid bruit and the maximum percentage diameter stenosis of the origin of the symptomatic internal carotid artery were correlated. The prevalence of mild disease (diameter stenosis greater than or equal to 25%) of the symptomatic internal carotid artery was 57%, and if an ipsilateral carotid bruit was heard the probability of mild stenosis rose to 92%. The prevalence of moderate disease of the symptomatic internal carotid artery (stenosis greater than or equal to 50%) was 39%, and if a bruit was heard the probability doubled to 78%. The prevalence of severe internal carotid disease (stenosis greater than or equal to 75%) was 22%, and if a bruit was heard the probability was more than double, at 49%. The direct cost to both the NHS and the private health sector of investigating patients with symptomatic carotid ischaemia was estimated for several strategies of carotid artery imaging and expressed in terms of financial cost and number of strokes after angiography incurred in detecting all patients with diameter stenosis of the symptomatic internal carotid artery of greater than or equal to 25%, 50%, or 75%. To detect diameter stenosis of the internal carotid artery of greater than or equal to 25% it is most cost effective to proceed directly to cerebral angiography in patients with a carotid bruit over the symptomatic carotid bifurcation and to screen patients without a carotid bruit by duplex carotid ultrasonography; patients in whom duplex ultrasonography discloses stenosis of greater than or equal to 25% are then referred for cerebral angiography. To detect only more severe internal carotid disease (stenosis of greater than or equal to 50%) the same policy applies, unless the local duplex ultrasonographic service is particularly efficient and reliable, when it is probably most cost effective and safer to screen all patients by this method irrespective of the findings on cervical auscultation. To detect stenosis of 75% or greater it is most cost effective to screen all patients with duplex ultrasonography, whether a carotid bruit is present or not, because this approach reduces the number of angiograms required, is the least expensive, and results in the least number of strokes after angiography.

CONCLUSIONS

Patients selection for cerebral angiography before carotid endarterectomy needs to be appropriate and cost effective. Sound clinical evaluation and duplex carotid ultrasound are required. The findings of this study should not be applied to other medical centres without first considering possible differences in the prevalence of carotid artery disease, the efficiency and reliability of duplex ultrasonography, the local complication rates of cerebral angiography, and the local costs of the imaging procedures.

Correlation of carotid bruits and carotid atherosclerosis detected by B-mode real-time ultrasonography

The extent of carotid atherosclerosis evaluated by B-mode real-time ultrasound and the presence of bruits established by carotid phonoangiography were determined in 1,107 patients. Unilateral bruit was associated with increased atherosclerosis compared with no bruit (p less than or equal to 0.0001). However, there was no association between laterality of the bruit and the degree of atherosclerosis (p = 0.66). There was marginal evidence that patients with bilateral bruits had more severe atherosclerosis than patients with unilateral bruit (p = 0.046). The relation between bruit and atherosclerosis categorized by B-mode ultrasound was not sufficient to reliably predict the presence or absence of disease in an individual patient, though the presence of a bruit should be viewed as a risk factor for, or an indicator of, increased risk of systemic atherosclerosis.

Predictive value of cervical bruit for the detection of obstructive lesions of the internal carotid artery. Data from 2000 patients

Between January 1982 and June 1985, 2000 patients with either symptoms of cerebrovascular insufficiency (1873) or asymptomatic cervical bruits (127) were studied at the Surgical Department of the University of Brescia (Italy). Of these, 441 presented a mono- or bilateral cervical bruit. The value of the bruit as indicator of an obstructive pathology of the extracranial carotid artery was evaluated in comparison with the findings of Doppler spectrum analysis. A stenosis or occlusion of the internal carotid artery was present in 51% of the patients with a bruit (homolateral to the bruit in 91% of the cases) and in 9% of those without a bruit. Stenoses of a medium-high degree were those more often associated with the bruit. Both in patients with bruit and in those without bruit the age and the severity of the presenting symptoms significantly influenced the rate of association with lesions of the internal carotid artery was present in 51% of the patients with a bruit (homolateral to the bruit in 91% of the cases) and in 9% of those without a bruit. Stenoses of a medium-high degree were those more often associated with the bruit. Both in patients with bruit and in those without bruit the age and the severity of the presenting symptoms significantly influenced the rate of association with lesions of the internal carotid artery.

Doppler and duplex sonography of the cervical arteries and correlations with other examinations. A field study in a population over forty years

Of the population of a small Tyrolean village, 185 (56%) of the 329 inhabitants over 40 years were investigated by means of Doppler and duplex sonography, electroencephalography (EEG), electrocardiography (ECG), and neurological examination. Four subjects (2%) previously had a transitory ischemic attack (TIA) or stroke in the carotid territory. Sonographically detectable abnormalities in one or more extracranial arteries were present in 42 (23%) persons. Of the 14 subjects with more than slight abnormalities in the common or internal carotid artery two were symptomatic. Two additional cases with TIA or stroke did not show relevant lesions on sonographic examination. The presence of narrowing in the extracranial artery was not related to risk factors (hypertension, smoking, obesity) or abnormalities on ECG and EEG. This study shows 1) that the clinical relevance of ultrasound screening of the carotid arteries in an average population is 15%; 2) that significantly more patients with TIAs or strokes are found in the group with more severe sonographic findings (p = 0.001) than in the group with normal ultrasound results.

Carotid and lower extremity arterial disease in elderly adults with isolated systolic hypertension

The prevalence of carotid and lower extremity arterial disease was assessed in a healthy population of 56 elderly adults with isolated systolic hypertension. Duplex scans were performed to determine the extent of carotid disease, and postexercise ratios of ankle to arm systolic blood pressure were measured to assess lower extremity arterial disease. Internal carotid stenosis was found in 38% (21 of 56) of subjects and lower extremity arterial disease in 42% (23 of 55). The strongest predictor of internal carotid stenosis was lower extremity arterial disease. Independent risk factors for lower extremity arterial disease were smoking, internal carotid stenosis, and age. A measure of extent of carotid plaque was found to correlate with age, carotid stenosis, male sex, history of smoking, and total cholesterol. The high prevalence of peripheral vascular disease in this population may be related to their age and blood pressure. The high correlation between carotid stenosis and lower extremity arterial disease suggests that persons with peripheral vascular disease should be assessed and treated for atherosclerotic disease in general.

Clinical applications of noninvasive carotid artery testing

The management of patients with cerebral transient ischemic attacks and carotid artery stenosis remains controversial. Noninvasive techniques help to determine which patients require surgical intervention without exposing the majority of patients to the risk and discomfort of invasive procedures. Measurement of ophthalmic artery pressure by ophthalmodynamometry or oculoplethysmography gives a representation of perfusion pressure in the internal carotid artery circulation. Doppler ultrasound studies can define the extent of obstruction to flow at the carotid artery bifurcation and assess collateral flow from the external carotid artery. Real time B-mode ultrasonography can detect nonobstructive ulcerated plaque in the carotid artery bifurcation. Employing these examinations in a test battery can identify hemodynamically significant lesions, which are more likely to precipitate a stroke. The information obtained from these studies can be utilized in patients with episodes of cerebral transient ischemic attacks, asymptomatic carotid artery bruits and vertebrobasilar insufficiency. Noninvasive carotid artery testing is also useful in screening patients with nonspecific symptoms, such as dizziness or light-headedness, which may be related to decreased flow in the carotid circulation. Noninvasive carotid artery testing can provide valuable anatomic and physiologic information required in the appropriate management of patients with cerebrovascular disease. It is of particular value in managing patients with heart disease who are at high risk for complications from invasive procedures.

The natural history of carotid arterial disease in asymptomatic patients with cervical bruits

A prospective study was initiated in January 1980 to follow with Duplex scanning a consecutive series of 167 asymptomatic patients with cervical bruits. Patients were seen at six month intervals for the first year and yearly thereafter. Based on previously validated criteria, disease at the carotid bifurcation was classified into 6 categories: Normal, 1-15% diameter reduction, 16-49%, 50-79%, 80-99%, and occlusion. Patients were evaluated to assess: the occurrence of new neurological symptoms, the stability of the lesions at the carotid bifurcation, and the possible role of risk indicators on disease changes. During follow-up, ten patients became symptomatic (6 with TIA's and 4 with stroke). The development of symptoms was accompanied by disease progression in 8 patients. By life table analysis, the annual rate occurrence of symptoms was 4%. The mean annual rate of disease progression to a greater than 50% stenosis was 8%. When progression in all categories was considered, 60% of the sides showed some disease aggravation. The presence of or progression to a greater than 80% stenosis was highly correlated (p = 0.00001) with either the development of a total occlusion of the internal carotid artery or new symptoms. The major risk factors associated with disease progression were cigarette smoking, diabetes mellitus, and age. Those patients under 65 years of age were most likely to show progression. Despite high rates of disease progression, this study further supports the contention that it is prudent to follow a conservative course in the management of asymptomatic patients presenting with a cervical bruit.(ABSTRACT TRUNCATED AT 250 WORDS)

[Spontaneous clinical course of asymptomatic vascular processes of the extracranial cerebral arteries. Further results of a long-term prospective study]

The natural history of a prospectively selected group of neurologically asymptomatic patients with extracranial arterial disease (EAD) was studied. 35 of 184 patients died over a period of follow-up of four years (mean = 21 months). Only four of them had a stroke, while coronary artery disease was the far more common cause of death (n = 19). Among those patients still alive 12 reported transient ischaemic attacks, two a stroke, and 116 remained asymptomatic--only two patients could not be followed. Thus by life-table analysis, the cumulative stroke rate was only 6%, irrespective of death or survival, about the same as the average risk of death in a normal population (5%). However, the probability of EAD progression was 88% as revealed by subsequent continuous-wave Doppler analysis of both the carotid and vertebral arteries in the neck. Neither the degree of initial EAD nor its progression during follow-up were found to represent significant indicators of the patient's cerebrovascular risk. Since the majority of symptomatic patients did not proceed to frank strokes but presented with TIAs, prophylactic surgical treatment may reasonably be delayed.

Ultrasound screening for internal carotid disease-II. Sensitivity and specificity of a single site periorbital artery test

Supraorbital artery blood flow was examined non-invasively with continuous wave Doppler-shifted ultrasound and spectral analysis. The results were used to assess the ipsilateral internal carotid artery in 155 patients undergoing carotid angiography. The ultrasound parameters used were the temporal artery occlusion test and A/B ratios of both resting and augmented supraorbital sonagrams. A retrospective study showed this combination to have a sensitivity of 65% for internal carotid disease which did not encroach on the lumen and for all other angiographically demonstrated lesions an average sensitivity of 94% and specificity of 92%. Augmented supraorbital pulses were more sensitive for detection of carotid artery disease than resting supraorbital pulses. Of the 61 lesions in which both resting and augmented supraorbital A/B ratios were obtained, the augmented supraorbital pulse detected 48 (79%) whilst the resting supraorbital pulse detected 29 (48%). Localised carotid bruits were poor indicators of carotid artery disease, having a sensitivity of only 27%.

The superiority of combined continuous wave Doppler examination over periorbital Doppler for the detection of extracranial carotid disease

Non-invasive examination of 431 vessels in 333 patients with cerebrovascular disease in all stages was performed in order to compare the reliability of the periorbital Doppler test alone and together with the more difficult insonation of the carotid arteries in the neck (combined Doppler). These findings were compared with those of subsequent arteriography. Extracranial obstructive (greater than 50%) carotid disease was detected with 100% sensitivity by the combined Doppler, but with only 48% sensitivity by the periorbital indirect test. The specific ability of both methods to identify non-stenotic carotid arteries (less than 50%) was similar at about 98%. Only the combined Doppler examination reliably differentiated various degrees of obstruction, comparable to that obtained with arteriography. Non-obstructive plaques could not be detected or excluded by either Doppler test. More refined methods will be necessary for their evaluation.

Auscultation of cervical and ocular bruits in extracranial carotid occlusive disease: a clinical and angiographic study

The clinical and angiographic features of cervical and ocular bruits were correlated in 50 consecutive patients with severe extracranial internal carotid artery occlusive disease. Cervical bruits, generally localized to the carotid bifurcation, were highly associated (P = 0.004) with "tight" (residual lumen less than or equal to 2 mm) internal carotid artery stenosis, but significantly less often with a widely patent or occluded internal carotid artery. Angiographic features of a "slow-flow" state through a patent, but "tight" stenosis were identified as the apparent explanation for the absence of bruit in some patients. A unilateral ocular bruit contralateral to the side of internal carotid artery occlusion occurred in 9 of 10 patients, more often than an associated cervical bruit, and was interpreted as a sign of augmentation flow.

Stroke risk from symptomless extracranial arterial disease

The natural history of a prospectively selected group of neurologically symptomless patients with extracranial arterial disease (EAD) was studied. 23 of 122 patients died over a period of follow-up of from eleven to thirty-six months (mean = seventeen), but only 3 from stroke and 10 from cardiac failure. Among those patients still alive 8 reported transient ischaemic attacks, 1 a stroke, and 90 remain symptomless. Thus, by life-table analysis, the cumulative stroke rate was only 7%, irrespective of death or survival, the same as the average risk of death in a normal population. However, by subsequent continuous-wave Doppler examination of carotid and vertebral arteries, the probability of EAD progression was 85%. Involvement of initially unaffected arteries occurred either alone (25) or in combination with a deterioration of the original stenosis (14)--the latter alone was seen in 9 patients. A combined carotid and vertebral lesion was found to be the only significant indicator of cerebrovascular risk, which was six times greater than that for unilateral or bilateral carotid lesions.

Incidence of asymptomatic extracranial arterial disease

Investigations of the incidence and the extent of the asymptomatic early stages of extracranial arterial disease (EAD) have been restricted for methodical reasons. Direct Continuous Wave-Doppler examination has given highly accurate results in the location and correct estimation of the degree of EAD both for the carotid (97%) and the vertebral arteries (90%), as shown from a detailed comparison with carotid (n = 604) and vertebral (n = 426) angiograms. Compared with this degree of reliability, the validity of normal auscultation for the diagnosis of EAD is shown to be poor: if bruits are taken as the only signs of associated EAD in patients with systemic atherosclerosis, only 27.6% in a group of 123 patients would have been correctly diagnosed. This parallels the number of false-positives (22.6%) in patients with normal results. The frequency and degree of EAD was studied by the use of direct Doppler examination in 2009 neurologically asymptomatic patients admitted either with severe vascular (n = 375) or coronary atherosclerosis (n = 262) or with high-risk factors (n = 1370). The frequency was significantly higher (32.8%) in patients with peripheral vascular disease than in those with coronary artery disease (6.8%) and in risk-factor patients (5.9%). The combination and degree of vessel involvement are presented in detail and their possible prognostic significance discussed.

Quantitative carotid phonoangiography

One hundred and sixteen carotid artery bruits were assessed using quantitative phonoangiography (spectral bruit analysis - SBA). This technique uses the averaged break frequency of the bruit to calculate the diameter of he residual lumen at the site of stenosis. Biplanar contrast arteriography was performed on 43 (37%) of the sides. All 116 sides were also evaluated with an ultrasonic Duplex scanner. Ten (8.6%) bruits could not be analyzed by the SBA, leaving 106 sides in which the residual lumen diameter could be estimated. The diameter of the vessel at the site of stenosis estimated by SBA and arteriography were compared and found to agree within 1 mm of each other in 85% of patients. A linear relationship was demonstrated between absolute lumen diameter and percent stenosis as measured from the arteriograms, but we were unable to correlate the absolute diameter of hte residual lumen as assessed by arteriography or SBA with the assessment of the degree of the stenosis derived from spectral analysis of the pulsed Doppler signal. The significance of these findings is discussed with relevance to the clinical application of spectral bruit analysis.

Importance of noninvasive ultrasonic-Doppler testing in the evaluation of patients with symptomatic carotid bruits

An ultrasonic Duplex scanner was used to estimate the site and degree of extracranial arterial disease in two groups of patients with asymptomatic bruits. In the first 100 patients only the extent of disease was assessed with 37% of the sides with bruits having high-grade stenoses (greater than 50% diameter reduction) and one-half having lesions which narrowed the internal carotid artery by less than 50%. Seven percent were found to be normal. The remaining 6% had occlusion of the internal carotid artery. In a second group of 81 patients, the effect of the reported findings of the Duplex scan on patient management was reviewed. Only 13 patients underwent angiography and 11 of these were in patients with high-grade stenoses. Five carotid endarterectomies were performed and in each case, the patient had bilateral high-grade lesions. The implications of this diagnostic approach are discussed as well as the need for prospective studies of patients who present with an asymptomatic bruit.

Functional anatomy of extracranial arteries in occlusive vascular diseases by direct continuous wave Doppler sonography

Doppler sonography of supratrochlear and neck arteries permits a determination of the direction and speed of flow. By compression of distal branches, the external carotid artery can be recognized, the occipital artery can be distinguished from the vertebral, and the direction of flow in the supratrochlear artery can be ascertained regardless of the artery's coiling. Compression of the arm can reveal subclavian steal. In order to localize a stenosis the vessel is followed by the probe. The accuracy of Doppler sonography is approximately 96%, and while the method may miss the diagnosis of slight stenoses and ulcerations, it nevertheless appears to be superior to all other indirect, noninvasive techniques that are currently available.

Diagnosis by ultrasound of severe carotid artery disease in patients undergoing cardiopulmonary bypass operations

A non-invasive method using continuous wave Doppler shift ultrasound and spectral analysis was used as a screening test for severe carotid artery disease in patients undergoing cardiopulmonary bypass operations. One hundred and eighty-eight patients were examined before cardiac surgery (91 for ischaemic heart disease, 17 for ischaemic heart disease and valve replacement, 66 for valve replacement alone, and 14 for congenital abnormalities). The mean age of the 108 patients suffering from ischaemic heart disease was 54 years (+/- 8) and that of the 80 patients admitted either for valve replacement alone or for congenital abnormalities was 52 years (+/- 12). Five of the 108 patients suffering from ischaemic heart disease were found to have severe occlusive disease of the internal carotid artery by the ultrasound test, while the test was normal in the other two groups. Patients with severe carotid artery disease proceeded to carotid arteriography and endarterectomy before the planned heart operation.

Cerebrovascular evaluation: assessment of Doppler scanning of carotid arteries, ophthalmic Doppler flow and cervical bruits

In 38 patients who underwent cerebrovascular evaluation followed by angiography the Doppler ultrasound scanning technique was found to be an excellent screening procedure for detecting marked stenosis (greater than 50%) or occlusion of the internal carotid artery (93% correlation). It is noninvasive, easily reproducible and can be performed by a qualified technician. The major problems are: the inability to detect ulcerated plaques without marked stenosis, the requirement for patient cooperation (lying still for periods of 15 minutes), and the fact that it assesses only the extracranial circulation. Screening with just the directional ophthalmic Doppler flow signal yielded a high percentage of false negatives (13%). The presence of a cervical bruit may indicate an underlying stenosis of the internal carotid artery, but may also be due to stenosis of the external carotid artery or other factors such as increased blood flow, vessel tortuosity, etc. (12% false positives). Absence of a cervical bruit does not exclude internal carotid artery disease (ulcerated nonstenotic plaque or occlusion).

Doppler haematotachography: problems in interpretation and new applications

The Doppler-echographic examination (HTG) seems to be developing into a screening method for the detection of abnormalities of the large cerebropetal vessels. An appraisal is made of the possibilities and limitations of the HTG based on the literature, a group of 250 patients and several relevant case histories. In general an abnormal HTG curve seems to warrant further diagnostic investigations (angiography). A normal HTG curve not be considered sufficient reason to omit an angiographic examination. A number of new applications of the HTG examination are mentioned.

A new sign of occlusion of the origin of the internal carotid artery

When the origin of the internal carotid artery is occluded, the transmission of cardiac sounds along the carotid stops at the site of the occlusion. This is a new neurovascular sign which is being reported.

Noninavasive angiography for the diagnosis of carotid artery disease using Doppler ultrasound (carotid artery Doppler)

To detect stenosis in the carotid artery with a bidirectional continuous-wave Doppler ultrasound device, the following noninvasive procedure, applied on 800 patients and compared with 249 angiograms of 186 patients, has proved to be about 90% reliable. Measurements of flow signals were taken over the terminal branches of the ophthalmic artery (supratrochlear and supraorbital arteries) and averaged. Compression of superficial temporal and facial arteries revealed flow direction and common carotid artery compression revealed the supplying blood vessel and the effectiveness of the circle of Willis. Measurements over the common carotid arteries were used to evaluate peripheral resistance. A set of eight criteria was used; the diagnostic value of each criterion was calculated by comparing 138 pathological Doppler findings in 123 patients with the angiograms. If reverse flow direction in supratrochlear or supraorbital artery was used alone, only 43% correct diagnoses would have resulted. A more severe stenosis is not necessarily correlated with a more weighted criterion; a subset of criteria is less efficient than the combination of all criteria. Application during 32 extracranial endarterectomies on 28 patients informed the surgeon immediately about the hemodynamic effect of the surgical intervention. Rethrombosis was diagnosed in two patients by postoperative Doppler examination.

Amaurosis fugax: diagnostic and therapeutic aspects

The three to eight-year follow-up study of 34 patients with unilateral amaurosis fugax (AF) suggests the following points: (1) A significant number of frequent unilateral AF patients suffer from small ulcerative plaques or irregular stenoses without any bruit in the neck or major changes in ophthalmodynamometry (ODM). The most important diagnostic test in these cases is angiography. (2) Surgery in patients with frequent unilateral AF seems to be more successful than anticoagulation. (3) No treatment cannot be considered a policy of "benign neglect" and may result in serious complications. (4) Cholesterol plaques, carotid bruits, and abnormal ODM are suggestive of carotid artery disease in unilateral AF. However, the absence of these signs is not helpful in differentiating carotid artery from cardiac origin of the emboli. (5) Heart disease may be the main etiological factor in a few patients with AF. It plays a major role in mortality regardless of the type of treatment.