Longitudinal characterization of carotid siphon calcifications: A CT-based population study

Background and aims: Carotid siphon calcifications (CSC) are recognized markers of cerebrovascular aging and vascular injury. Despite their relevance, longitudinal data on CSC progression is limited. In this study, we evaluated factors associated with CSC progression in middle-aged and older adults. Methods: We conducted a prospective cohort study in a rural Ecuadorian population, assessing CSC progression using non-enhanced CT scans carried out an average of 7.4 years apart. CSC were graded using Woodcock's scale (absent, mild, moderate, and severe), with progression defined as an increase of ≥1 grade in the follow-up CT. Poisson and multinomial logistic regression models assessed associations between CSC progression and baseline demographics and cardiovascular risk factors. Results: The study included 396 individuals aged ≥40 years (mean age: 57.5±11.2 years; 45% women). At baseline, 236 (60%) participants had absent; 87 (22%) mild; and 73 (18%) moderate CSC. Follow-up CTs revealed CSC progression in 17 (4.3%) participants, with an overall rate of 0.78 events per 100 person-years. Smoking (IRR: 3.83; 95% C.I.: 1.3–11.3) and arterial hypertension (IRR: 3.67; 95% CI: 1.5–8.63) emerged as the strongest modifiable predictors of CSC progression. Participants with a poor smoking status showed a progression of 2.61 events per 100 person-years versus 0.68 in non-smokers. Hypertensives had a progression rate of 1.51 events versus 0.41 in normotensives. Conclusions: CSC may progress over time – albeit slowly – in individuals with advancing age, smoking history, and hypertension. The low rate of progression suggests that routine CT-based monitoring is unlikely to be justified in clinical practice. Instead, our findings highlight the importance of controlling modifiable risk factors to mitigate vascular injury.