David Brill
Carotid bruits are associated with an elevated risk of myocardial infarction (MI) and cardiovascular death, a meta-analysis in The Lancet has shown.
The rate of MI in patients with a carotid bruit – a sound caused by turbulent blood flow within the artery – was 3.69 per 100 patient-years, compared to 1.86 for those without a bruit. For cardiovascular death the rates were 2.85 and 1.11, respectively, per 100 patient-years.
“The presence of a carotid bruit suggests that there is systemic atherosclerosis,” said Dr. Ching Chi Keong, a consultant at the National Heart Centre in Singapore.
“Even in an asymptomatic patient with a carotid bruit we should assess the patient to confirm the degree of carotid stenosis and if present, no matter how minor it is, we should treat the patient for established atherosclerosis,” said Ching.
The meta-analysis, conducted by researchers at the Walter Reed Army Medical Center in Washington DC, included 22 articles involving 17,295 patients. The total number of patient-years of follow-up was 62,413.5. [Lancet 2008 May 10;371(9624):1587-94]
Only four of the trials included in the analysis permitted direct comparison of patients with and without bruits. The pooled odds ratios from these studies were 2.27 (95 percent CI 1.49 – 3.49) for cardiovascular death and 2.15 (95 percent CI 1.67 – 2.78) for MI.
Previous studies had focused on the link between carotid bruits and cerebrovascular disease but failed to find a significant correlation, and some organizations in the US have recommended against routine auscultation. Ching believes, however, that this process should be a standard part of cardiovascular risk assessment.
“Some doctors may just overlook or skip this step in view of time constraints but it is free, takes no longer than 30 seconds, and in patients who might be at risk of atherosclerosis we should do this routinely,” he said.
Dr. Teo Swee Guan, a consultant cardiologist at the National University Hospital, was not surprised to find that bruits are associated with cardiovascular disease but not cerebrovascular disease.
“This study confirmed that carotid bruits are simply a marker of atherosclerotic disease. And we know more patients with atherosclerosis die of cardiovascular disease than of stroke,” said Teo, who agreed that auscultation for bruits should be performed in all patients who are at risk for coronary heart disease.
“It is non-invasive, inexpensive and a marker of atherosclerotic disease, which helps in overall cardiovascular risk stratification,” he concluded.
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