[Carotid stenotic-obliterative lesions. Distribution in 16,379 subjects 45-75 years of age]

The epidemiology of carotid occlusive disease in a resident population is still unclear. Data of some interest are available only from cohort studies on prevalence and incidence of neck bruits, whose correlation to carotid stenosis is weak.

A large population study (O.P.I. programme) has been carried out in the USSL (sanitary district) n. 69 of Lombardia (Italy), consisting of a two staged screening based on physical examination and neck vascular ultrasound imaging of men and women aged 45 to 75. This paper reports preliminary results of the screening.

From 1/29/1990 to 3/31/1992, 16,379 people agreed to be enrolled in the O.P.I. programme and underwent physical examination and CW Doppler ultrasound carotid exploration. Some 1,734 (10.6%) were selected for second level non invasive screening: 1,587 attended, and underwent second physical examination and carotid echo-flow imaging, to confirm carotid lesions. Population was divided into 7 age groups by 5 year intervals. According to the degree of stenosis, people affected with carotid occlusive disease were classified into five groups: < 50%; 50-70%; > 70%; occlusion; bilateral lesions of any degree.

Carotid echo-flow imaging confirmed that 404 people harbored carotid occlusive disease (2.5%); 270 (66.8%) had unilateral stenosis or occlusion and 134 (33.2%) bilateral lesions. The 538 affected carotid arteries were equally distributed on both sides. Male to female ratio was 1.7:1 (p < 10(-6). Prevalence of the lesions was 0.43% among the youngest subjects and gradually rose up to 8.14% among the oldest age group (p < 10(-6). Ninety-five percent of subjects affected with severe carotid lesions (occlusion, unilateral stenosis > 70% or bilateral lesions) were 56 or older. Echographic appearance was determined in 439 of 514 stenosis (85.4%): ulcerated plaque was evident in 13.3% of stenosis > 70%, but only in 0.7% of stenosis < 50% (p = 0.02). Otherwise plaque calcification was dominant in 32.5% of stenosis < 50% and in 13.3% of stenosis > 70% (p = 0.0006).

The prevalence of atherosclerotic carotid occlusive disease in people resident in the USSL n. 69 aged 45 to 75 years was 2.5%. Males were more severely affected than females. Prevalence and severity of the disease increase with ageing.