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

Clinical outcomes of radiation-induced carotid stenosis: A systematic review and meta-analysis

OBJECTIVES

Clinical outcomes of radiation-induced carotid stenosis are still unclear. Therefore, a systematic review and meta-analysis is needed to evaluate the short- and long-term outcomes after interventions to treat radiation-induced carotid stenosis.

METHODS

PubMed, EMBASE, the Cochrane Library and Web of Science were searched from 1 January 2000 for relevant RCTs and observational studies which reported outcomes after carotid endarterectomy (CEA) and carotid angioplasty and stenting (CAS) for carotid stenosis induced by radiation. Risk of bias were assessed through different scales according to study design. I² statistic were used to evaluate the heterogeneity, and meta-regression were performed to investigate the source of heterogeneity. Visual inspection of funnel plots was used to judge publication bias.

RESULTS

A total of 26 studies with 1002 patients were included. CEA was performed in 364 patients and CAS in 638 patients. The overall estimated rate of short-term stroke was 0.19% (95% CI: 0-0.90%), and the rate of long-term stroke was 2.68 % (95% CI: 1.19-4.57%). The rate of cranial nerve injury in CEA group was significantly higher than that in CAS group [risk ratio (RR): 6.03, 95% CI: 1.63-22.22, P = .007]. The univariate regression analysis showed that the risk of stroke in CAS group were significantly higher than CEA group in both short- and long-term [incidence rate ratio (IRR): 3.62, 95% CI: 1.21-10.85, P = 0.22; IRR: 2.95, 95% CI: 1.02-8.59, P = .046, respectively].

CONCLUSIONS

This systematic review provided the worldwide profile of outcome of treatment for radiation-induced carotid stenosis, and also found that CEA can yield better results for these patients than CAS. Nonetheless, as large-scale studies have not yet been conducted, and there is a definite need for further studies in the future.

Association between carotid artery stenosis and peripheral artery disease: Evaluation by screening carotid ultrasonography (cross-sectional study)

We aimed to investigate the association between carotid artery stenosis and peripheral artery disease (PAD) by screening carotid ultrasonography (CUS).From January 2012 to December 2015, 231 consecutive patients who had undergone preoperative CUS for PAD were included in this study. A radiologist assessed the degree of internal carotid artery (ICA) stenosis by using the North American Symptomatic Carotid Endarterectomy Trial (NASCET). Severe (>70%) ICA stenosis was evaluated based on the type of vascular surgery, PAD lesion, and ankle-brachial index (ABI). Data were analyzed using multiple logistic regression analysis and the χ test.Among 231 PAD patients, multilevel lesions revealed significantly higher incidence of severe ICA stenosis than iliac and infrainguinal lesion (22.5% vs 9.4% vs 8%: P = .016). Age (odds ratio [OR]: 1.05, 95% confidence interval [CI]: 1.00-1.12: P = .035), chronic kidney disease (CKD, OR: 6.19, 95% CI: 2.04-45.04: P = .013), and cerebral vascular disease (CVD, OR: 4.08, 95% CI: 1.13-16.46: P = .037) were significant risk factors of severe ICA stenosis in multivariate analysis. Prevalence of severe ICA stenosis according to ABI in PAD was not significant.Preoperative screening by CUS provides valuable information onasymptomatic carotid artery stenosis (ACAS) that can identify severe ACAS patients who are at high risk of stroke and to consider more intensive management of carotid disease in PAD patients. CUS can be a useful noninvasive preoperative screening imaging tool for PAD patients with multilevel lesions, aged > 65 years old, with CKD and CVD.

The risk of carotid stenosis in head and neck cancer patients after radiation therapy

OBJECTIVES

Head and neck radiotherapy (RT) is a risk factor for cerebrovascular disease. We performed a retrospective cohort study to evaluate carotid artery stenosis (CAS) incidence in head and neck cancer (HNC) patients undergoing RT, characterizing associated risk factors.

MATERIALS AND METHODS

Records were retrospectively reviewed for HNC patients undergoing carotid ultrasound screening after definitive or adjuvant RT between January 2000 and May 2016. CAS was defined as ≥50% stenosis on imaging, stroke, or transient ischemic attack. Actuarial CAS rates were calculated by Kaplan-Meier method. Univariate and multivariate analyses predicted CAS risk based on carotid dosimetric and clinical parameters.

RESULTS

366 patients met inclusion criteria. Median time from RT completion to last follow-up was 4.1 yr. Actuarial risk for CAS was 29% (95% CI 22-36%) at 8 years. Univariate analysis showed that smoking (HR 1.7; 95% CI 1.1-2.7), hyperlipidemia (HR 1.6; 95% CI 1.03-2.6), diabetes (HR 2.8; 95% CI 1.6-4.8), coronary artery disease (HR 2.4; 95% CI 1.4-4.2), and peripheral artery disease (HR 3.6; 95% CI 1.1-11.6) were significantly associated with increased CAS. In multivariate analysis, diabetes was predictive of time to CAS (HR 1.9; 95% CI 1.1-3.4). Carotid dose parameters were not significantly associated with CAS.

CONCLUSIONS

CAS incidence is high after head and neck radiotherapy, gradually rising over time. No clear dose-response effect between carotid dose and CAS was identified for HNC patients. Carotid artery screening and preventative strategies should be employed in this high-risk patient population.

Advantages of Selective Use of Intraluminal Shunt in Carotid Endarterectomy: A Study of 122 Cases

Objectives: To assess the advantage of selective use of shunt in carotid endarterectomy (CEA) under local anesthesia. Materials and Methods: A total of 122 consecutive patients fulfilling international guidelines were included. Shunt was used selectively only in cases of bilateral severe carotid artery occlusive disease or in those patients who developed neurological symptoms on clamping of carotid artery. Follow up was done weekly for one month; then every month for 3 months; and then every 3 months for a year. Results: Shunt was used only in 5% (n = 6) patients. Of these, 2.5% (n = 3) patients were those who developed neurological symptoms on clamping the internal carotid and deployment of shunt resulted in complete resolution of symptoms. 2.5% (n = 3) had severe bilateral carotid stenosis and shunt was deployed. One of these patients developed stroke which was permanent. There was no mortality. The mean procedure time was 170 min in patients in whom shunt was used, when compared with 100 min in patients without shunt (P = 0.003). Conclusion: Use of shunt in carotid endarterectomy under local anesthesia as selective policy has an advantage in terms of cost effectiveness, operation time and prevention of potential complications.

Rapid High-Volume Population Screening for Three Major Risk Factors of Future Stroke: Phase I Results

Three proximate risk factors for stroke are carotid stenosis, atrial fibrillation, and hypertension. Phase I of this prospective study was designed to establish the prevalence of these conditions among a population of health maintenance organization beneficiaries by using a rapid screening protocol in order to risk-stratify patients for appropriate management and subsequent cohort analysis. Patients at a tertiary care medical center were screened for stroke risk by using directed history, a 3-minute carotid “quick-scan” protocol, an EKG lead II rhythm strip, and bilateral arm blood pressures. Patients with any abnormal result underwent specific diagnostic consultation with vascular surgery, cardiology, or primary care. These evaluations included formal carotid duplex ultrasound, 12-lead EKG ± Holter monitor, and 5-day blood pressure check. Patients were then stratified into risk cohorts for appropriate management and future analysis of stroke incidence and outcomes. In 8 hours on a single day in October 2002, 294 patients (mean age 69) were screened. Combining history with results of screening and diagnostic tests, the overall prevalence of carotid stenosis was 6% (n= 17/294), atrial fibrillation 7% (n= 21/294), and severe hypertension 5% (n= 16/294). Fifty-nine patients (20%) screened positive for carotid stenosis by “quick-scan,” and 29% (n= 17/59) of these had confirmed stenosis (>50%) in 1 or both arteries by formal duplex. The prevalence of confirmed carotid stenosis was 37% among those screening positive for 1 artery (odds ratio [OR] 14.6; p <0.001) and 75% among those screening positive for both (OR 74.7; p <0.001). Significant independent predictors of carotid stenosis by multivariate analysis included coronary artery disease or myocardial infarction, smoking, stroke or transient ischemic attack, male gender, and white race (all p <0.05). The prevalence of confirmed stenosis was 10% with any 3 predictors alone (OR 2.5; p <0.05), 31% with any 4 (OR 21.2; p <0.001), and 50% with all 5 (OR 46.5; p <0.001). Thirty-three patients (11%) were found to have a previously unidentified and untreated arrhythmia, and 12% (n= 4/33) of these had confirmed new atrial fibrillation; 158 patients (54%) had moderate hypertension and 16 (5%) had severe hypertension (>180/100). Overall, 82% (n= 242/294) of patients screened required additional diagnostic tests. Based on these results, 11% (n= 31/294) of patients were stratified as high risk, 64% (n= 188/294) as moderate risk, and 25% (n= 75/294) as low risk for future stroke. Rapid and efficient screening of a large population for stroke risk factors is feasible. The prevalence of undiagnosed, unsurveilled, and untreated carotid stenosis, atrial fibrillation, and severe hypertension is significant, as 75% of patients screened had 1 or more confirmed major risk factors for stroke. Phase II of this study will investigate the degree of stroke risk reduction possible with a multidisciplinary approach to early identification and aggressive treatment of these risks.

Prevalence of significant carotid artery stenosis in Iranian patients with peripheral arterial disease

BACKGROUND

Generalized screening for carotid artery stenosis with carotid duplex ultrasonography in patients with peripheral arterial disease is controversial.

OBJECTIVES

The aim of the present study was to determine the prevalence of significant internal carotid artery (ICA) stenosis in a group of Iranian patients with peripheral arterial disease.

METHODS

We prospectively screened 120 patients with a known diagnosis of peripheral vascular disease for carotid artery stenosis. Based on the angiographic assessment of abdominal aorta and arteries of the lower extremities, patients with stenosis greater than 70% in the lower extremity arteries were included. A group of healthy individuals aged ≥ 50 years was recruited as a control. Risk factors for atherosclerosis including smoking, diabetes mellitus, hyperlipidemia, ischemic heart disease, and cerebrovascular disease were recorded. Common carotid arteries (CCAs) and the origins of the internal and external arteries were scanned with B-mode ultrasonography. Significant ICA stenosis, > 70% ICA stenosis but less than near occlusion of the ICA, was diagnosed when the ICA/CCA peak systolic velocity ratio was ≥ 3.5.

RESULTS

Ninety-five patients, with a mean age of 58.52 ± 11.04 years, were studied. Twenty-five patients had a history of smoking, six patients had a history of coronary artery disease, six patients had hypertension, and ten patients had diabetes mellitus. Significant ICA stenosis was present in four patients (4.2%) with peripheral arterial disease in one healthy individual (1%) of the control group (P > 0.05). In terms of the risk factors for atherosclerosis, no statistically significant relationship was found between individual atherosclerotic risk factors and significant ICA stenosis (P > 0.05).

CONCLUSION

The prevalence of significant ICA stenosis in Iranian patients with peripheral arterial disease is low. In addition, there is no relationship between individual atherosclerotic risk factors and significant ICA stenosis.

Controversies in vascular screening art versus science

Whether or not to screen asymptomatic members of the general public for various forms of vascular disease is a controversial issue with huge medical, social, and financial ramifications. This article reviews several criteria for determining the appropriateness of vascular screening, including: (1) is it possible to detect occult vascular disease ;early'?; (2) what should we screen for, and how should we do it?; (3) who should be screened?; and (4) what standards for vascular screening should be set? While some of these controversies may ultimately be resolvable using an evidence-based approach, it is apparent that there are issues which will not be amenable to strict scientific analysis. Individualized approaches to screening will therefore remain the rule for the foreseeable future.

Guidelines for Screening of Extracranial Carotid Artery Disease: A Statement for Healthcare Professionals from the Multidisciplinary Practice Guidelines Committee of the American Society of Neuroimaging; Cosponsored by the Society of Vascular and Interventional Neurology

The aim of this new statement is to provide comprehensive and timely evidence-based recommendations on the screening for asymptomatic carotid artery stenosis in the general population and selected subsets of patients. Recommendations are included for high-risk persons in the general population; patients undergoing open heart surgery including coronary artery bypass surgery; patients with peripheral vascular diseases, abdominal aortic aneurysms, and renal artery stenosis; patients after radiotherapy for head and neck malignancies; patients following carotid endarterectomy, or carotid artery stent placement; patients with retinal ischemic syndromes; patients with syncope, dizziness, vertigo or tinnitus; and patients with a family history of vascular diseases and hyperhomocysteinemia. The recommendations are based on prevalence of disease, anticipated benefit, and concurrent guidelines from other professional organizations in selected populations.

When should ultrasonography be used to detect asymptomatic carotid atheroma in diabetic patients?

INTRODUCTION

While guidelines for detection of silent myocardial and lower limb ischemia are established, data on screening asymptomatic carotid lesions remain scarce. However, such screening would be costly. Since the prevalence of diabetes increases constantly, it is necessary to keep screening costs low by setting up criteria for the selection of patients at risk of ischemic cerebral attack and those who will need medical or surgical attention. Diabetic patients, particularly type 2, often have many reasons to take anti-platelet agents and lipid-lowering therapy. Therefore, carotid ultrasonography screening would have little effect on treatment modification or on glycaemia and blood pressure objectives, but could improve the prognosis of operable lesions.

IN THE GENERAL POPULATION

A one-time screening program was considered worthwhile if the prevalence of severe asymptomatic stenosis was over 20%. The presence of another arterial occlusive disease or other cardio-vascular risk factors could be a major argument for screening.

IN DIABETIC PATIENTS

Carotid intima-media thickness (IMT) was recognized as a reliable prognostic indicator of heart attack and stroke. It worsens with duration of diabetes, renal failure, cardiac neuropathy and poor long term glycaemic control.

CONCLUSION

Our review suggests that a one-time carotid ultrasonography screening could be recommended for diabetic patients with coronary disease or lower limb atherosclerosis (secondary prevention), all diabetic patients above 60 years of age, smokers, hypertensive and with hypercholesterolemia; type 1 diabetic patients with poor long term glycaemic control; all type 2 diabetic patients with renal failure, a long duration of ill-controlled diabetes or with a carotid bruit. This literature review should be analyzed with caution. It would be helpful to organize a prospective long term study on all types of diabetic patients, including a carotid ultrasonography screening program by experienced radiologists.

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.

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.

Screening for asymptomatic internal carotid artery stenosis and aneurysm of the abdominal aorta: comparing the yield between patients with manifest atherosclerosis and patients with risk factors for atherosclerosis only

OBJECTIVE

The purpose of this study was to investigate whether screening for internal carotid artery stenosis (ICAS) and aneurysm of the abdominal aorta (AAA) is indicated in patients with either manifest atherosclerotic disease or with only risk factors for atherosclerosis.

STUDY DESIGN

Data were obtained for 2274 patients enrolled in the SMART study, an ongoing single-center, prospective cohort study of patients referred to our vascular center with manifest atherosclerotic disease (peripheral atherosclerotic disease [PAD]; transient ischemic attack [TIA], stroke, or ICAS; AAA; angina pectoris; or myocardial infarction [MI]) or with only risk factors for atherosclerosis (diabetes mellitus, hypertension, hyperlipidemia). The presence of ICAS or AAA was determined with duplex scanning and ultrasonography.

RESULTS

The prevalence of ICAS 70% or greater is low in patients with risk factors for atherosclerosis only (1.8%-2.3%), intermediate in patients with angina pectoris or MI (3.1%), and highest in patients with PAD (12.5%) or AAA (8.8%). The prevalence of AAA 3 cm or larger is low in patients with risk factors for atherosclerosis only (0.4-1.6%), intermediate in patients with angina pectoris or MI (2.6%), and highest in patients with PAD (6.5%) or TIA, stroke, or ICAS (6.5%). The prevalence of AAA larger than 5 cm is low in all of the considered patient groups. The yield of screening can be optimized through selection on the basis of simple patient characteristics. In patients with PAD, selecting those with advanced age (>54 years) increased the prevalence of ICAS to 21.8%. Selecting patients with lower diastolic blood pressure (<83 mm Hg) increased the prevalence of ICAS to 17.9%. In patients with both advanced age and lower diastolic blood pressure, the prevalence of ICAS increased to 34.7%. Selecting patients with advanced age increased the prevalence of AAA 3 cm or larger to 9.6%. In patients with TIA, stroke, or ICAS, selecting those with advanced age increased the prevalence of AAA 3 cm or larger to 8.2%. Selecting patients with taller stature (>169 cm) increased the prevalence of AAA 3 cm or larger to 9.3%. In patients with advanced age and taller stature, the prevalence of AAA 3 cm or larger increased to 13.1%.

CONCLUSIONS

Screening for ICAS should be limited to patients referred with PAD or AAA, especially those with advanced age or with low diastolic blood pressure. Screening for AAA should be limited to patients referred with PAD or with TIA, stroke, or ICAS, particularly those with advanced age or tall stature. In patients referred with angina pectoris or MI and those referred with only risk factors for atherosclerosis, screening cannot be endorsed.

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.

Routine preoperative carotid duplex scanning in patients undergoing open heart surgery: is it worthwhile?

It has been reported that carotid screening may be cost-effective in patient populations in which the prevalence of severe carotid stenosis exceeds 4.5%. In order to identify potential patient populations who might benefit from carotid screening, we examined the results of preoperative duplex scanning in patients undergoing open heart surgery. Between January 1995 and July 1998, 3708 patients (59% male, 41% female) underwent open heart surgery at our institution. Of these, 3081 underwent coronary artery bypass grafting (CABG), 364 underwent valve replacement (VR), and 263 underwent CABG and VR. The ages of these patients ranged from 40 years to 98 years (mean 68 +/- 11 years). The risk factors analyzed included hypertension (HTN), 59%; smoking (Smk), 53%; and diabetes (DM), 33%. Patients were divided into three groups according to their age. Group A consisted of the 835 patients who were < or = 60 years old, group B consisted of 2474 patients ranging from 61 years to 80 years old, and group C consisted of 399 patients who were > or = 81 years old. All patients underwent bilateral preoperative carotid duplex scans at an Intersocietal Commission for the Accreditation of Vascular Laboratories (ICAVL)-accredited vascular laboratory. Statistical analyses were performed using chi-squared, Fisher's exact test, linear regression, and multivariate analysis. From our results we concluded that carotid screening is not recommended for patients under 60 years of age who are undergoing CABG unless they present with a minimum of two of the following major risk factors: hypertension, diabetes, or smoking. However, carotid screening is recommended for all patients undergoing open heart operations who are over the age of 60 years old, regardless of the absence of associated risk factors.