Reasons for Carotid Imaging Older Asymptomatic Patients
What are common reasons for asymptomatic patients to undergo carotid imaging?
Using the Veterans Health Administration database, the authors studied 4,127 Veterans, aged ≥65 years, who underwent carotid revascularization for asymptomatic carotid stenosis between 2005 and 2009. They then explored the reasons why the Veteran’s first carotid ultrasound test was ordered. A multidisciplinary panel assessed the appropriateness of all indications using a consensus process.
Of the 4,127 Veterans who underwent carotid revascularization for asymptomatic carotid stenosis, the mean age was 73.6 ± 5.9 years and 98.8% were men. There were 5,226 indications for 4,063 carotid ultrasounds that were ordered. The most common indications for imaging were carotid bruit (1,578, 30.2% of indications) and follow-up for a known carotid stenosis or history of carotid disease (1,087, 20.8% of indications). Multiple vascular risk factors were the third most common indication for carotid imaging. Reasons for carotid imaging were assessed as appropriate (227, 5.4% of indications), uncertain (3,387, 83.4% of indications), and inappropriate (458, 11.3% of indications). Dizziness/vertigo and syncope were among the most common inappropriate indications for carotid ultrasound imaging.
The authors concluded that carotid bruit and follow-up of carotid disease accounted for approximately one-half of all indications for carotid imaging in patients with asymptomatic carotid disease. The authors also concluded that strong consideration should be given to improving the evidence base around carotid testing given the large number of imaging tests assessed as uncertain appropriateness.
While the evidence for revascularization is quite strong in patients with symptomatic carotid disease, the evidence is not nearly as convincing for asymptomatic carotid stenosis. However, the majority of carotid imaging tests are in patients who are largely without stroke-like symptoms. This study highlights the frequency with which carotid ultrasound tests are ordered in asymptomatic older adults, and the lack of high-quality evidence to guide the appropriateness of these tests. In particular, there is significant discordance between major guideline recommendations on the use of carotid imaging in patients without a history of stroke or transient ischemic attack. Although this study only explored asymptomatic patients who eventually underwent carotid revascularization, similar reasons for carotid imaging would be expected for patients who never underwent carotid revascularization. Clinicians should consider the absolute benefits and harms associated with carotid revascularization in asymptomatic patients prior to ordering imaging tests if the patient does not have a prior history of stroke, transient ischemic attack, or recent stroke-like symptoms.
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