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

BACKGROUND

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.

PURPOSE

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.

MATERIALS AND METHODS

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.

RESULTS

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).

CONCLUSIONS

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.