The Barcelona-Asymptomatic Intracranial Atherosclerosis (AsIA) study: Prevalence and risk factors

Abstract 

Background and purpose

The ongoing population-based Barcelona-Asymptomatic Intracranial Atherosclerosis (Barcelona-AsIA) study is a prospective study that plans to investigate the natural history of asymptomatic intracranial atherosclerosis (AsIA) in a Caucasian-Mediterranean population, which remains unknown until now. The present study aims to determine the prevalence of AsIA and associated risk factors in the final study cohort.

Methods

Crossover, population-based study of a representative sample (randomly selected from our reference population) older than 50 with a moderate-high vascular risk assessed by the vascular equation REGICOR and prior history of neither stroke nor ischemic heart disease. Anthropometric, demographic, clinical data and blood samples were collected at baseline. All individuals underwent a complete extracranial and transcranial color-coded duplex (TCCD) examination. TCCD criteria were used to identify and classify the degree of intracranial stenoses.

Results

A total of 933 subjects (64% men, mean age 66.3 years) were included in the study. One or more intracranial stenoses were detected at baseline in 80 subjects (8.6%) of whom 31 (3.3%) had moderate-severe lesions. The higher the REGICOR scores the greater the prevalence of AsIA (6.6%, 10.2% and 25% for REGICOR scores 5–9, 10–14 and ≥15, p<0.001). Diabetes (OR 2.95; 95% CI (1.68–5.18); p<0.001), age (OR 1.05; 95% CI (1.02–1.08); p=0.001) and hypertension (OR 1.78; 95% CI (1.02–3.13); p=0.04) were independently associated with any degree of AsIA, while diabetes (OR 2.85; 95% CI (1.16–6.96); p=0.02) and age kept independently associated with moderate-severe AsIA.

Conclusion

The prevalence of AsIA and moderate-severe AsIA in stroke-free Caucasians with a moderate-high vascular risk were 8.6% and 3.3% respectively. Diabetes and age were independently associated with moderate-severe AsIA.

Keywords: Asymptomatic intracranial atherosclerosis, Stroke primary prevention, Prevalence studies, Risk factors in epidemiology