Carotid Bruit May Predict Cardiovascular Risk

By Charles Bankhead
WASHINGTON, 12 may 2008 -- Checking for carotid bruit can identify patients at high cardiovascular risk, a meta-analysis here suggested.Carotid bruit doubled the risk of myocardial infarction and almost tripled the risk of cardiovascular death, Christopher Pickett, M.D., of Walter Reed Army Medical Center, and colleagues reported in the May 10 issue of The Lancet.When the analysis was limited to studies that permitted direct comparison of patients with and without bruit, the risk of MI and cardiovascular death remained twice as high in those with bruit.
"Our findings accord with the notion that these atherosclerotic changes [that lead to bruit] might be indicative of system-wide vascular pathological change to include the coronary bed," the authors concluded. "Clinicians auscultating a carotid bruit should be concerned that atherosclerosis might not just reside solely in the carotid artery."
They added, "Since auscultation of the carotid is a swift and inexpensive test, it should be used in every patient who might be at risk for coronary heart disease to aid the clinician in assessment of cardiac risk."
The prognostic implications of carotid bruit have focused primarily on cerebrovascular events. However, carotid bruit has only weak predictive accuracy for cerebrovascular events in patients who are otherwise symptomatic, the authors noted.
As a result of the prognostic uncertainty of carotid bruit, screening recommendations vary. For example, the U.S. Preventive Services Task Force and the Canadian Task Force recommend against routine auscultation for carotid bruit, the authors continued. On the other hand, the American Academy of Family Physicians and other groups recommend screening auscultation in select patients.
"Carotid bruits are probably a better indicator of generalized atherosclerotic disease than of stroke risk, and several studies have suggested that patients with carotid artery disease are more likely to die from cardiovascular than from cerebrovascular disease," the authors said.
To examine bruits' predictive accuracy for cardiovascular death and MI, Dr. Pickett and colleagues analyzed data from 22 studies involving a total of 17,295 patients with 62,413.5 patient-years of follow-up. Median duration of follow-up was four years.
The analysis showed that patients with bruits had an MI rate of 3.69 per 100 patient-years versus 1.86 per 100 patient-years in those without bruits. The yearly rate of cardiovascular death was 2.85 versus 1.11 per 100 patient-years, respectively, for patients with and without bruits.
The design of four trials allowed direct comparisons of patients with and without bruits. In that analysis, patients with bruits had a two-fold greater risk of MI (OR 2.15, 95% CI 1.67 to 2.78) and cardiovascular death (OR 2.27, 95% CI 1.49 to 3.49).
In a commentary accompanying the article, Victor Aboyans, M.D., and Philippe Lacroix, M.D. of Dupuyten Hospital in Limoges, France, cited several limitations of the study and findings.
About a third of the study participants had existing cardiovascular disease. Bruit's influence on secondary prevention is unclear.
Bruit's prognostic value was not compared with cardiovascular risk scores, making the incremental value unknown.
Patients without bruit have other clinical signs that could have similar prognostic significance.
Despite those limitations, the editorialists suggested that evaluation of patients for bruit could be added to other simple tests for a simple office-based assessment capable of identifying high-risk patients.
"Prospective studies on asymptomatic patients are needed to study the prognostic value of a combination of simple clinical signs such as neck and groin auscultation and pulse palpation," said Drs. Aboyans and Lacroix. "Heart rate, pulse pressure, or blood-pressure difference between arms could also be considered."
They added, "These studies could narrow the indications of cardiovascular imaging techniques and make them more cost effective in developed countries. In developing countries, the same data could help make the best use of very limited resources dedicated to prevention of cardiovascular disease."
The authors and the editorialists declared no conflicts of interest.

Primary source: The LancetSource reference:Pickett CA, et al "Carotid bruits as a prognostic indicator of cardiovascular death and myocardial infarction: A meta-analysis" Lancet 2008.