Screening for asymptomatic carotid artery stenosis in patients older than 65 years

The risk of stroke related to asymptomatic carotid artery stenosis (ACAS) is known to be increased in the presence of high-grade or rapidly progressive stenosis. Identification of significant asymptomatic carotid artery stenosis is important because of the possibility of stroke-risk reduction, as observed after carotid artery stenting and endarterectomy. Information on the prevalence of ACAS in the general population is required for the recommendation of screening methods to identify patients who may need prophylactic treatment. We studied the prevalence and the grade of severity of extracranial carotid artery stenosis by means of Doppler-duplex sonography. Through gray-scale imaging and spectral Doppler waveform analysis, diameter reduction rate, peak systolic velocity and end diastolic velocity were measured. Degree of ICA stenosis was defined by the criteria of Society of Radiologists in Ultrasound Consensus Conference. When both carotid arteries were diseased, the more stenotic site was used for statistical analysis. We studied 482 patients, 215 women and 267 men whose ages ranged from 65 to 94 years (mean 71,4 years), living in Antalya. Of these, 372 patients were asymptomatic and 110 (22 transient ischemic attack, 88 stroke) were symptomatic. Risk factors included hypertension (60%), diabetes (28%), hyperlipidemia (52%), coronary artery dissease (33%) renal failure (6,8%), sedantary life (35%), obesity (64%) and smoking (39%). Overall, 31,1 % of patients were normal, 56,8 % had less than 50 % diameter stenosis, 5,8 % had 50-69 % stenosis, 4,5 % had severe stenosis of 70-99 %, and 1,6 % of patients carotid artery were occluded. While 372 patients were asymptomatic, 110 patients were symptomatic. Internal carotid artery stenosis of more than 50% were present in 58 (=12%) patients. In 32 of asymptomatic patients (8,6%) and 26 (4 transient ischemic attack, 22 stroke) of the symptomatic patients (23,6%), there was more than %50 stenosis in ICA. The incidence of significant carotid artery stenosis was similar in men and women. There were no significant gender differences. The frequency of carotid artery stenosis was significantly increased with age, smoking, renal failure and sedantary life, but not with hypertension, diabetes, hyperlipidemia, alcohol use and obesity. The frequency of carotid artery stenosis was significantly increased in patients with peripheral artery disease and coronary artery disease. It was also significantly increased in those with serebrovascular disease. Increase of intima-media thickness was also found to be significantly increased in patients with coronary artery disease (p<0.05). Prevalence and severity of carotid artery disease, intima-media thickness, prevalence of serebrovascular disease and peripheral artery disease were significantly correlated with age (p<0.05, r≤0.274). Atherosclerotic disease is common in patients over 65 years of age who have atherosclerotic risk factors. Some of these risk factors can be used to identify persons in the community at high risk for asymptomatic carotid artery stenosis. Doppler ultrasound screening in this subgroup may prove to be cost-effective and have an effect on stroke-free survival. Duplex-Doppler sonography is an excellent noninvasive method of screening for asymptomatic carotid artery stenosis and evaluation and follow-up of asymptomatic patients.