RESUMO
Background: Framingham risk score (FRS) has limitations and can underestimate risk. Carotid ultrasound to measure intima media thickness or plaques is recommended for cardiovascular risk assessment. Aim: To determine the prevalence of subclinical atherosclerosis in asymptomatic subjects classified as low and intermediate risk. Material and Methods: Cross-sectional study performed in subjects without cardiovascular disease. Cardiovascular risk was estimated using the Chilean FRS and the General Cardiovascular Disease FRS. Carotid ultrasound was performed in all subjects. We defined subclinical atherosclerosis as the presence of carotid plaque or intima media thickness greater than 75th percentile by gender and age. Results: We studied 203 subjects aged 47.2 ± 9.6 years (54% males). Mean intima media thickness was 0.62 ± 0.1 mm. An abnormal value was detected in 68 subjects (33%) and carotid plaques in 32 subjects (15.7%). Based on Chilean FRS, 96% were considered at low risk, 4% at intermediate, and none at high risk. In the low risk group the prevalence of abnormal intima media thickness and plaques was 40 and 14% respectively. Presence of plaques was more common in women than men (23 and 7% respectively, p < 0.01). According to the General Cardiovascular Disease FRS, 23% were at low, 39% at low intermediate and 28% at high intermediate risk. In the low risk group the prevalence of an abnormal intima media thickness was 34% and no subject had plaques. Conclusions: Carotid plaques were detected in Chilean subjects classified as having a low FRS risk. The underestimation of risk was higher in Chilean women.