Synergistic effects of lipoprotein (a) and fibrinogen on carotid plaque in patients with coronary artery disease

Background Elevated lipoprotein (a) [Lp (a)] and fibrinogen (Fib) are important factors contributing to the pathogenesis of atherosclerosis. Carotid plaque is a manifestation of carotid atherosclerosis, and previous studies have shown that Fib has a synergistic effect on Lp (a)-induced events. However, the effect of the combined action of Lp (a) and fibrinogen on carotid plaque has not been elucidated. Methods This was a cross-sectional study that screened a total of 3913 patients who attended the First Affiliated Hospital of Xinjiang Medical University with confirmed diagnosis of coronary artery disease (CAD) and carotid ultrasonography during 2019-2024. General clinical information, physical examination data, and laboratory tests were collected from the patients. Based on the results of carotid ultrasonography, the patients were divided into a group with carotid plaque (1123 cases) and a group without carotid plaque (2790 cases). Multifactorial logistic regression analysis was used to explore the correlation between Lp (a) and Fib levels and carotid plaque and the interrelationship between them. Results A total of 3913 patients were included, including 2666 males and 1247 females, and the incidence of carotid plaque was 28.7%, with significant differences in Lp (a) and Fib levels between the two groups with and without carotid plaque (P < 0.05) and a significant interaction effect. Multiple logistic regression analysis showed that for every tenfold increase in plasma Lp (a) levels (i.e., an increase of one logarithmic unit), the incidence of carotid plaque could increase by about 32% or so. After stratified analysis for age and sex, it was observed that carotid plaque was significantly associated with plasma Lp (a) levels in men and in patients aged < 60 years (male: OR = 1.301, 95% CI 1.051-1.611; age < 60 years: OR = 1.373, 95% CI 1.076-1.753). Plasma Fib levels were associated with carotid plaque in patients of different sexes and age groups, and there was a significant synergistic effect of Lp (a) and Fib on carotid plaque (P-interaction < 0.05). Conclusions Elevated levels of Lp (a) and Fib are independent risk factors for combined carotid plaque in patients with coronary artery disease, and there is a synergistic effect of both on carotid plaque. Therefore, plasma Lp (a) and Fib levels of patients should be focused on for better treatment of carotid plaque and prevention of ischemic stroke.