Prevalence of and risk factors for extracranial internal carotid artery stenosis in Korean Type 2 diabetic patients

Aims: The objectives of this study were to evaluate the prevalence of and risk factors for extracranial internal carotid artery stenosis in Type 2 diabetic patients. Methods: This study included 406 patients aged 40-79 years with Type 2 diabetes (male 55.4%, female 44.6%). Both carotid arteries of each patient were examined by carotid duplex scanning. The duplex ultrasound criteria based on the North American Symptomatic Carotid Endarterectomy Trial (NASCET) measurement method were used for the identification of carotid stenosis. Results: Extracranial internal carotid artery stenosis ≥ 40% by velocity criteria was detected in 5.2% of the patients. The prevalence of carotid stenosis increased with advancing age: 1.0% at 40-49 years of age, 5.0% at 50-59 years, 7.3% at 60-69 years and 9.5% at 70-79 years. The degree of stenosis was > 70% in 42.9% of patients with stenosis, Bilateral stenosis was detected in 14% of patients. Of the patients with ≥ 40% carotid stenosis, 33% had a decreased ankle-brachial index, 38% had a previous history of stroke, and only one patient (5%) had a documented history of coronary artery disease. Multivariate analysis, including variables determined to be significantly different by univariate analysis between patients with or without ≥ 40% stenosis, indicated that age, systolic blood pressure and high-density lipoprotein (HDL)-cholesterol (inverse correlation) were independent risk factors associated with carotid stenosis. Conclusions: Carotid duplex scanning is a useful strategy in identifying carotid stenosis in older Type 2 diabetic patients with high systolic blood pressure, or low levels of HDL cholesterol. The early identification and subsequent appropriate management of carotid stenosis, particularly in this group of patients, may facilitate efforts to reduce the incidence of macrovascular complications.