Cardiovascular risk associated with carotid bifurcation plaques producing < 50% stenosis and its modulation by presence of common femoral plaques: A cohort study

Background: The aims were to determine the 10-year risk of atherosclerotic cardiovascular disease (ASCVD) in individuals free from ASCVD (a) in the presence of carotid bifurcation plaques (CBP) < 3-mm thick and ⩾ 3 mm in comparison to a normal vessel wall and (b) the risk modulation in the presence or absence of additional common femoral bifurcations with plaques (CFBP) in a cohort study. Methods: A total of 1000 subjects aged 58.4 ± 10.5 years, free from ASCVD, were followed up for 15.2 ± 4.9 years (mean ± SD). The primary endpoint was a composite of first time fatal or nonfatal 10-year ASCVD events. Results: The 10-year risk of ASCVD was 6% in the absence of carotid plaques; 10% in the presence of unilateral and 23% in the presence of bilateral < 3-mm plaques (adjusted hazard ratio [HR] 1.65 [95% CI 1.11–2.47] and 2.03 [95% CI 1.32–3.00], respectively); and 29% for unilateral and 63% for bilateral 3–5 mm plaques (adjusted HR 2.40 [95% CI 1.41–4.09] and 3.78 [95% CI 1.77–8.06], respectively). In those with unilateral or bilateral < 3-mm CBP in the presence of two CFBP, the 10-year risk of ASCVD was 26% and 37% (adjusted HR 3.01 [95% CI 1.38–6.58] and 2.52 [95% CI 1.55–4.10], respectively). The 10-year risk was 2% in those without CBP or CFBP and 26% in those with two CFBP only. Conclusions: The presence of a < 3-mm CBP may be associated with a significant ASCVD risk, especially if bilateral. This risk is better defined by the additional presence or absence of two CFBPs.