Do you still feel the thrill if you discover a Carotid bruit on your patient ? No pun intended 😁. As tech & evidence-based approaches in medicine advance & time afforded per patient recedes, a thorough physical exam appears to be losing it’s shine….and relevance. So are carotid bruits as useless as the G in ‘Lasagna’ ?
A study published in 2009 looked at 686 stroke-free people around the age of 70, found that a carotid bruit was 56% sensitive, 98% specific, with a positive predictive value of 25%, and a negative predictive value of 99% for detecting carotid stenosis of greater than 60% . Similar findings in a study published in 2002. However, the predictive power of a bruit for significant carotid disease or strokes is better when other cardiovascular (CV) risk factors or symptoms (TIA/CVA) are present. For example, this study of asymptomatic bruits in diabetics found a 6-times higher risk of stroke in 2 years in those with bruits compared to those without. A review of various carotid studies mentioned on this study of bruits & stenosis in patients with established CAD undergoing CABG ( bypass) surgery shows that the sensitibity and positive predictive value of a bruit was higher in studies that included patients with symptoms. The study itself showed almost 50% of those bypass patients had some extent of carotid disease – not surprising given that carotid disease is a proxy of atherosclerotic vascular disease in general.
That being said, an abscence of a bruit does not imply lack of carotid disease given that sensitivity is very low and that in very severe stenosis, the blood flow is too weak to cause a bruit. Interestingly this older article notes upto 20% children under age 15 have bruits – a normal finding – while upto 8.2% in adults above 75 age have bruits. It also notes bruits are actually heard less frequently as stenosis extent exceeds 90%.
So although not as useless as a gift of Dehydrated Water – if you hear a bruit in a patient without active or past stroke symptoms, consider it in context of their CV risk, which should be CALCULATED AND DOCUMENTED using scoring systems like Framingham 10-year risk calcualtor or Reynolds risk calculator (use this if family history is reliably present) . If risk is significant, screen for carotid stenosis with carotid duplex and add medical therapy if detected. If carotid disease is not severe, they need surveillance scans. If the bruit document before disappears, it can mean the disease has worsened and needs investigation.
In patients with TIA or strokes, carotids will be scanned anyway – whether bruit or not – but missing carotid stenosis after hearing a bruit in non-stroke patients can mean a lawsuit ! This and This are examples of lawsuits from skipped carotid stenosis evaluations in high-risk patients resulting in strokes later despite physician documenting carotid bruits. An analysis of malpractice claims regarding carotid disease published in 2019 showed majority carotid related lawsuits were filed for failure to diagnose and treat carotid disease – and 60% of the cases about failure to treat resulted in favor of the patient.
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