The prognostic significance of asymptomatic carotid bruits in the elderly

Abstract

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. S troke is an important cause of morbidity, mortality, loss of independence, and institutionalization. Age is a major risk factor for stroke, with rates doubling in each decade after 55 independent of other known risk factors. 1 Hypertension, cigarette smoking, diabetes, and atrial fibrillation are also major risk factors for stroke. 2 Although the development of symptomatic carotid disease (e.g., transient ischemic attacks [TIAs]) identifies persons at high risk of subsequent strokes, most strokes occur without previous symptoms. 3 Thus, the identification and management of asymptomatic elderly at high risk of subsequent stroke is an important public health issue. In asymptomatic persons with atrial fibrillation, the utilization of oral anticoagulants reduces the risk of stroke. 4 However, the prevention of stroke for asymptomatic persons without atrial fibrillation depends largely on reducing known risk factors and, in appropriate candidates, identifying persons with surgically remediable high-grade carotid artery stenosis. [2][3][4] Auscultation for carotid bruits is noninvasive and inexpensive, but its utility in detecting asymptomatic older adults at increased risk of stroke has been incompletely studied. 5 Early studies found an increased risk of carotid bruits among persons suffering stroke compared with control subjects 6,7 ; however, these studies were nonblinded and potentially subject to observer bias. Population-based prospective studies found that persons with carotid bruits were at higher risk of subsequent stroke, 8-10 but age-specific risks were not reported. In contrast, a study of nursing home residents aged 75 years or older found no increased risk of stroke among persons with asymptomatic carotid bruits. However, sample size was small, and the generalizability of this finding to less frail elderly is not known. 11 Given the age-related prevalence of carotid bruits, and the paucity of data on the utility of neck auscultation to predict stroke in older adults, we conducted a retrospective cohort study of Systolic Hypertension in the Elderly Program (SHEP) participants to determine the risk of stroke associated with asymptomatic carotid bruits.

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

“…36 Unfortunately, this protocol relies upon limited predictive power of auscultation of the cervical carotid arteries for bruits, rather than duplex ultrasound, a significantly more accurate screening method. 37,38 However, formal duplex evaluations are time consuming and expensive, and despite excellent accuracy have not been shown to be cost-effective in screening for carotid stenosis. 39 A rapid, accurate, and inexpensive 3-minute "quick scan" carotid ultrasound protocol was utilized in this study to counter this disadvantage.…”

A Computational Method for Analyzing the Biomechanics of Arterial Bruits

“…Moreover, such a modality could be used for longitudinal tracking of patient health. For all these reasons, there is a renewed impetus to transform auscultation into a quantitative and accurate method [3,[7][8][9][10][11].…”

Carotid Bruits and Cerebrovascular Disease Risk

“…For example, the Systolic Hypertension in the Elderly study found carotid bruits to weakly predict cerebrovascular events with a relative risk of stroke of 1.3, 4 whereas the Evans County Study found a strong relationship with a relative risk of 4.1 for the combined event rate of transient ischemic attacks (TIAs) and stroke. 5 The uncertainty about the prognostic implications of a carotid bruit and the difficulty in managing asymptomatic carotid stenosis has led some organizations to recommend against routine auscultation for carotid bruits.…”