Segment and side specific determinants of carotid atherosclerotic burden: evidence for a distinct left internal carotid artery phenotype

Background and aims Carotid atherosclerosis is an important feature in patients with cerebrovascular events, but its determinants may vary across arterial segments and sides. We assessed segment- and side-specific determinants of carotid atherosclerotic burden. Methods We studied 177 patients aged 18–65 years who were hospitalized with acute ischemic stroke or TIA and underwent carotid ultrasonography. Atherosclerotic involvement of bilateral common carotid arteries, carotid bifurcations and internal carotid arteries was assessed using a Burden of Disease (BoD) score. We examined segment-specific associations between BoD, stenosis severity and cardiovascular risk factors. Results Plaques were more frequent at the carotid bifurcation and in the internal carotid artery than in the common carotid artery. After Bonferroni correction, age and hypertension were associated with BoD in the carotid bifurcation and internal carotid segments bilaterally; hypertension was also associated with left common carotid BoD (*p* = 0.003). BMI was associated with right bifurcation and internal carotid BoD (*p* = 0.007 and *p* = 0.005), Lp(a) >30 mg/dL with left internal carotid BoD (*p* = 0.002), and fibrinogen with left common carotid BoD (*p* = 0.005). The multivariable model for the left internal carotid artery explained the largest proportion of variance (R² = 0.274), with contributions from hypertension (0.092), Lp(a) >30 mg/dL (0.084), BMI (0.036), fibrinogen (0.035) and atrial fibrillation (0.027). Associations with stenosis severity were less consistent (*n* = 16–54). Conclusions In this symptomatic cohort, carotid atherosclerotic burden showed segment- and side-specific associations with cardiovascular risk factors. The broader range of associations in the left internal carotid artery is hypothesis-generating and requires confirmation in larger prospective cohorts.