Identification by Ultrasound Evaluation of the Carotid and Femoral Arteries of High-Risk Subjects Missed by Three Validated Cardiovascular Disease Risk Algorithms

Atherosclerotic cardiovascular disease (ASCVD) events are the leading cause of death in the United States and globally. Traditional global risk algorithms may miss 50% of patients who experience ASCVD events. Noninvasive ultrasound evaluation of the carotid and femoral arteries can identify subjects at high risk for ASCVD events. We examined the ability of different global risk algorithms to identify subjects with femoral and/or carotid plaques found by ultrasound. The study population consisted of 1,464 asymptomatic adults (39.8% women) aged 23 to 87 years without previous evidence of ASCVD who had ultrasound evaluation of the carotid and femoral arteries. Three ASCVD risk algorithms (10-year Framingham Risk Score [FRS], 30-year FRS, and lifetime risk) were compared for the 939 subjects who met the algorithm age criteria. The frequency of femoral plaque as the only plaque was 18.3% in the total group and 14.8% in the risk algorithm groups (n = 939) without a significant difference between genders in frequency of femoral plaque as the only plaque. Those identified as high risk by the lifetime risk algorithm included the most men and women who had plaques either femoral or carotid (59% and 55%) but had lower specificity because the proportion of subjects who actually had plaques in the high-risk group was lower (50% and 35%) than in those at high risk defined by the FRS algorithms. In conclusion, ultrasound evaluation of the carotid and femoral arteries can identify subjects at risk of ASCVD events missed by traditional risk-predicting algorithms. The large proportion of subjects with femoral plaque only supports the use of including both femoral and carotid arteries in ultrasound evaluation.