Utility of routine carotid duplex screening in patients who have claudication

The recently published Asymptomatic Carotid Atherosclerosis Study (ACAS) demonstrated the benefit of performing carotid endarterectomy in selected asymptomatic patients who have > 60% carotid stenoses. It therefore becomes clinically important to identify the subgroups of patients who have a sufficiently high incidence of high-grade carotid stenosis to warrant routine carotid duplex screening.

To determine the incidence of asymptomatic carotid disease in patients who had a chief complaint of claudication, we evaluated 188 patients who had claudication and no history of cerebrovascular symptoms. After a complete history was taken and a physical examination performed, patients underwent standard lower-extremity noninvasive vascular laboratory studies and carotid duplex scanning. Carotid duplex findings were interpreted by the Strandness criteria. Associated atherosclerotic risk factors were assessed (patient age, male sex, diabetes, hypertension, smoking history, lipid levels, history of coronary artery disease, coronary or vascular surgery, and family history of cerebrovascular disease). Presence of a carotid bruit was also noted. Univariate analysis, logistic regression, and odds ratios were performed to identify subgroups of patients that had an increased incidence of significant carotid disease.

Of the 188 patients with claudication who were screened, 8% had an internal carotid artery stenosis of 16% to 49%, 21.8% had a stenosis that exceeded 50%, and 2.7% had an occluded internal carotid artery. The presence of a carotid bruit on physical examination was predictive of a > or = 50% internal carotid artery stenosis (p = 0.027). The ankle-brachial index was highly predictive of the presence of carotid stenoses in an inverse relationship (p = 0.001). Patient age approached significance (p = 0.143). Patients older than 65 years of age who had claudication, an ankle-brachial index less than 0.7, and a carotid bruit had a 45% incidence of significant carotid disease. The atherosclerotic risk factors of male sex, diabetes, hypertension, hyperlipidemia, smoking history, coronary history, previous coronary or vascular surgical history, and family history were not predictive of the presence of a > 50% carotid stenosis.

In patients who seek medical attention with the chief complaint of claudication and who have no cerebrovascular symptoms, there is a 24.5% incidence of a > 50% internal carotid artery stenosis or occlusion on duplex examination. Select subsets of these patients have upwards of a 45% incidence of significant asymptomatic carotid disease. All patients who seek medical attention with claudication should therefore undergo routine carotid duplex screening to detect asymptomatic high-grade stenosis.