The rational clinical examination. Does this patient have a clinically important carotid bruit?

Physical exam myths: listening for carotid artery bruits in stroke patients

When a patient presents to the emergency department with a neurologic deficit and a cerebrovascular event is included in the differential diagnosis, the classic recommendation is to examine the carotid artery and assess for the presence of a bruit. The diagnostic yield and utility of this practice has seldom been called into question. This critical appraisal will review the practice of listening for a carotid artery bruit (CAB) in suspected stroke patients and analyze its clinical utility, including the sensitivity and specificity of a CAB for detecting a significant lesion and the potential impact a CAB may have on the investigation and disposition of such patients.

Additional prognostic value of physical examination, exercise testing, and arterial ultrasonography for coronary risk assessment in primary prevention

BACKGROUND

The choice of noninvasive tests used in primary prevention of cardiovascular diseases must be based on medical evidence. The aim of this study was to assess the additional prognostic value, over conventional risk factors, of physical examination, exercise testing, and arterial ultrasonography, in predicting a first coronary event.

METHODS

A prospective cohort study was conducted between 1996 and 2004 (n = 2,709), with follow-up in 2006 (response rate 96.6%). Participants had no history or symptoms of cardiovascular disease and had a standardized physical examination, a cardiac exercise testing, and carotid and femoral ultrasonography at baseline. Incident cases of definite coronary events were recorded during follow-up.

RESULTS

Over the Framingham risk score, femoral bruit, positive exercise test, intima-media thickness >0.63 mm, and a femoral plaque provided significant additional information to the prediction model. The addition of the exercise test to the traditional risk factors, then the intima-media thickness and lastly the presence of femoral plaques, produces incremental increases in the area under the receiver operating characteristic curve (0.73-0.78, P = .02) and about a 50% increase in the positive predictive value (15.8%-31.4%), with no effect on the negative predictive value (96.4%-96.9%).

CONCLUSION

Physical examination, exercise testing, and arterial ultrasonography provide incremental information on the risk of coronary event in asymptomatic adults. Exercise testing and femoral ultrasonography also improve the accuracy of the risk stratification.

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.

Incidence of perioperative stroke after neck dissection for head and neck cancer: a regional outcome analysis

OBJECTIVE

To determine the incidence of perioperative stroke in patients undergoing a neck dissection.

SUMMARY BACKGROUND DATA

The incidence of perioperative stroke in non-head and neck surgery is between 0.08 and 0.2%. In contrast, a critical review of the literature identified 2 studies stating the incidence of perioperative stroke in head and neck surgery to be 3.2% and 4.8%. The implications of these results are significant because they suggest a potential need for preoperative screening and/or intervention for carotid artery pathology.

METHODS

This historical cohort study was conducted using discharge data for all neck dissections performed in a geographically-defined health region in Alberta, Canada, from 1994 to 2002. Subjects were selected for study if they had an assigned ICD-9CM procedure code for a neck dissection at one of the region's 3 adult-care hospitals. Our main outcome measure was perioperative stroke.

RESULTS

Patients (n = 499) were identified as having had a neck dissection (mean age 56.5 +/- 15.3 SD, 65.3% male). Seven patients had ICD-9CM codes for postoperative central nervous system complications (incidence of 1.4%). However, on chart review, only one had had a true perioperative stroke corresponding to an incidence of 0.2% (95% confidence interval 0.01, 1.12). No missed strokes were found in a confirmatory random review of 10% of charts.

CONCLUSIONS

The incidence of perioperative stroke in this study is significantly lower than that previously stated in the literature. This suggests that preoperative screening and/or intervention for carotid artery disease may not be necessary in this patient population.

Improving the physical diagnosis skills of third-year medical students: a controlled trial of a literature-based curriculum

OBJECTIVE

To determine if a literature-based physical diagnosis curriculum could improve student knowledge, skill, and self-confidence in physical diagnosis.

DESIGN

Prospective controlled trial of an educational intervention.

SETTING

Required internal medicine clerkship for third-year medical students at Brown Medical School.

PARTICIPANTS

Third-year medical students who completed the internal medicine clerkship during the academic year 1999-2000: 32 students at 1 clerkship site received the intervention; a total of 50 students at 3 other clerkship sites served as controls.

INTERVENTION

Physical diagnosis curriculum based on 8 articles from the Journal of the American Medical Association's Rational Clinical Examination series. Intervention students met weekly for 1 hour with a preceptor to review each article, discuss the sensitivity and specificity of the maneuvers and findings, and practice the techniques with an inpatient who agreed to be visited and examined.

MEASUREMENTS AND MAIN RESULTS

Physical diagnosis knowledge for the 8 topics was evaluated using a 22-item multiple choice question quiz, skill was evaluated using trained evaluators, and self-confidence was assessed using an end-of-clerkship survey. Intervention students scored significantly higher than the control group on the knowledge quiz (mean correct score 70% vs 63%, P =.002), skills assessment (mean correct score 90% vs 54%, P <.001), and self-confidence score (mean total score 40 vs 35, P =.003), and they expressed greater satisfaction with the physical diagnosis teaching they received in the clerkship.

CONCLUSION

This physical diagnosis curriculum was successful in improving students' knowledge, skill, and self-confidence in physical diagnosis.

Carotid artery disease and stroke during coronary artery bypass: a critical review of the literature

OBJECTIVES

to determine the role of carotid artery disease in the pathophysiology of stroke after coronary artery bypass (CABG).

DESIGN

systematic review of the literature.

RESULTS

the risk of stroke after CABG was 2% and remained unchanged between 1970-2000. Two-thirds occurred after day 1 and 23% died. 91% of screened CABG patients had no significant carotid disease and had a <2% risk of peri-operative stroke. Stroke risk increased to 3% in predominantly asymptomatic patients with a unilateral 50-99% stenosis, 5% in those with bilateral 50-99% stenoses and 7-11% in patients with carotid occlusion. Significant predictive factors for post-CABG stroke included; (i) carotid bruit (OR 3.6, 95% CI 2.8-4.6), (ii) prior stroke/TIA (OR 3.6, 95% CI 2.7-4.9) and (iii) severe carotid stenosis/occlusion (OR 4.3, 95% CI 3.2-5.7). However, the systematic review indicated that 50% of stroke sufferers did not have significant carotid disease and 60% of territorial infarctions on CT scan/autopsy could not be attributed to carotid disease alone.

CONCLUSIONS

carotid disease is an important aetiological factor in the pathophysiology of post-CABG stroke. However, even assuming that prophylactic carotid endarterectomy carried no additional risk, it could only ever prevent about 40-50% of procedural strokes.

Part II. Evidence-based medicine: a passing fancy or the future of primary care?

Reliable experimental evidence provides a firm scientific foundation for only a minority of the clinical decisions primary care practitioners must make each day. Thus clinicians' experience and judgment must complement and supplement their knowledge of published research studies. This presents a dynamic and difficult challenge to the practitioner--one that is magnified when combined with the never ending influx of medical information, with patients' and physicians' uneasiness with clinical uncertainty, and with new external pressures to standardize care. With these factors in mind, this article will review evidence-based medicine, a process and philosophy for the practice and teaching of clinical medicine that has sparked much controversy in recent years. Clinical scenarios commonly encountered in adult primary care--acute low back pain, hypertension, and screening for vascular disease--illustrate some strengths and limitations of evidence-based medicine.

The prognostic significance of asymptomatic carotid bruits in the elderly

OBJECTIVE

To determine the association between asymptomatic carotid bruits and the development of subsequent stroke in older adults with isolated systolic hypertension.

DESIGN

Retrospective cohort study.

SETTING

The Systolic Hypertension in the Elderly Program (SHEP), a 5-year randomized trial testing the efficacy of treating systolic hypertension in noninstitutionalized persons aged 60 years or older. From the original 4,736 SHEP participants, we identified a cohort of 4,442 persons who had no prior history of stroke, transient ischemic attack, or myocardial infarction at randomization.

MEASUREMENTS AND MAIN RESULTS

The end point for this ancillary study was the development of a stroke. The average follow-up was 4.2 years. Carotid bruits were found in 284 (6.4%) of the participants at baseline. Strokes developed in 21 (7.4%) of those with carotid bruits and in 210 (5.0%) of those without carotid bruits. The unadjusted risk of stroke among persons with carotid bruits was 1.53 (95% confidence interval [CI] 0.98, 2.40). Adjusting for age, gender, race, blood pressure, smoking, lipid levels, self-reported aspirin use, and treatment group assignment, the relative risk of stroke among persons with asymptomatic carotid bruits was 1.29 (95% CI 0.80, 2.06). Among SHEP enrollees aged 60 to 69 years, there was a trend (p = .08) toward increased risk (relative risk [RR] 2.05; 95% CI 0.92, 4.68) of subsequent stroke in persons with, compared to those without, carotid bruits. However, among enrollees aged 70 years or over, there was no relation between carotid bruit and subsequent stroke (RR 0.98; 95% CI 0.55, 1.76). In no other subgroup of SHEP enrollees did the presence of carotid bruit independently predict stroke.

CONCLUSIONS

Although we cannot rule out a small increased risk of stroke associated with bruits in asymptomatic SHEP enrollees aged 60 to 69 years, the utility of carotid bruits as a marker for increased risk of stroke among asymptomatic elderly with isolated systolic hypertension aged 70 years or older is limited.