10-YEAR CEREBROVASCULAR MORBIDITY AND MORTALITY IN 68-YEAR-OLD MEN WITH ASYMPTOMATIC CAROTID STENOSIS

Objective-To study the natural course of carotid artery stenosis detec ted by ultrasonography. Design-Prospective cohort study. Baseline exam ination in 1982-3 included ultrasound examination of carotid arteries, measurement of ankle-brachial blood pressure index, and detection of atrial fibrillation by 24 hour ambulatory electrocardiography. Setting -Malmo, a city in southern Sweden with 230 000 inhabitants. Subjects-4 70 men aged 68 years randomly selected hom the population. Main outcom e measures-Incidence of stroke and transient ischaemic attack and all cause mortality during 10 years of follow up in relation to carotid st enosis, leg artery disease (ankle-brachial blood pressure index below 0.9), and atrial fibrillation. Results-Fifty men had a stroke; six of these were haemorrhagic. Another 11 had a transient ischaemic attack. Eighteen of the men with carotid stenosis (21.6 events/1000 person yea rs) and 43 of the men with normal carotid arteries (14.8 events/1000 p erson years) had a stroke or transient ischaemic attack (P = 0.188). M en with atrial fibrillation had an increased rate of cerebrovascular e vents (36.7/1000 person years (P = 0.048). The highest rate was found in men with asymptomatic disease of the leg arteries (38.6/1000 person years) (P < 0.001). The increased risk of stroke or transient ischaem ic attack in this group remained after multivariate analysis (relative risk 2.0; 95% confidence interval 1.1 to 3.7). Conclusions-In this co hort carotid stenosis was not associated with an increased risk of str oke. Part of this lack of association was explained by the high mortal ity from ischaemic heart disease in men with severe stenosis. Twenty s even of the 61 cerebrovascular events, however, occurred in men who ha d normal carotid arteries, normal ankle pressure, and no atrial fibril lation.