Extracranial carotid arterial disease: A prognostic factor for atherothrombotic brain infarction and cerebral transient ischemic attack

A prospective study investigated the prevalence of extracranial carotid arterial disease by carotid duplex ultrasonography, and evaluated its correlation with the incidence of atherothrombotic brain infarction or cerebral transient ischemic attack in 949 patients, mean age 82 ± 8 years. The mean follow-up period was 45 months. Of 949 patients, 37 (4%) had 80%- 100% extracranial carotid disease (mean follow-up, 24 ± 15 months), 113 (12%) had 40%-80% extracranial carotid disease (40 ± 19 months follow-up), and 799 (84%) had 0%-40% extracranial carotid disease (47 ± 14 months follow-up). The average annual incidence of atherothrombotic brain infarction was 37% in patients with 80%-100% extracranial carotid disease, 9% in patients with 40%-80% extracranial carotid disease, and 4% in patients with 0%-40% extracranial carotid disease. The average annual incidence of transient ischemic attack was 3% in patients with 80%-100% extracranial carotid disease, 2% in patients with 40%-80% extracranial carotid disease, and 1% in patients with 0%-40% extracranial carotid disease. The Cox proportional hazard model showed that among the variables evaluated, the severity of extracranial carotid disease correlated with the highest relative risk of developing atherothrombotic brain infarction (2.5x higher relative risk) or transient ischemic attack (2.8x higher relative risk). Patients with an earlier atherothrombotic brain infarction had a 2.1x higher probability of developing atherothrombotic brain infarction and a 1.9x higher chance of developing transient ischemic attack than those without an earlier atherothrombotic brain infarction. Age was a prognostic variable for new atherothrombotic brain infarction, and male sex was a prognostic variable for new transient ischemic attack.