Low Toe-Brachial Indices are Associated with Saccular Intracranial Aneurysms.

The prevalence of unruptured intracranial aneurysms increased significantly as toe-brachial index decreased.

• Prevalence of unruptured IAs was 16.3% in the low TBI group (<0.5), 8.3% in the borderline TBI group (0.50-0.69), and 4.1% in the normal TBI category (≥0.7)
• The difference across groups was statistically significant (p<0.001)
• Low TBI was associated with a fourfold higher prevalence of unruptured IAs compared with normal TBI

Low TBI was independently associated with unruptured intracranial aneurysms after sex- and age-adjusted multinomial regression including clinically relevant variables.

• Low TBI had an odds ratio of 3.59 (95% CI, 1.39–9.27) for unruptured IAs
• Female sex was also independently associated (OR 1.68; 95% CI, 1.06–2.673)
• Smoking history was independently associated (OR 2.56; 95% CI, 1.393–4.695)
• Low TBI showed the strongest association with unruptured IAs among the variables examined after adjustment

The study cohort comprised 2751 patients who underwent TBI assessment, of whom 776 with available cerebrovascular imaging or confirmed ruptured saccular IA were included.

• Patients were assessed at a tertiary hospital between January 2011 and December 2013
• The study was a retrospective cohort design
• Patients were stratified into three groups: low TBI (<0.5; n=473), borderline TBI (0.50–0.69; n=180), and normal TBI (≥0.7; n=123)
• The main outcome of interest was the potential association between TBI and the prevalence of saccular IAs

Intracranial aneurysms share common risk factors with atherosclerotic cardiovascular diseases, and a previously identified association between low ABI and higher prevalence of unruptured IAs motivated examination of TBI.

• Shared risk factors between IAs and atherosclerotic cardiovascular diseases include particularly smoking and hypertension
• Prior research by the same group found that low ABI is associated with a higher prevalence of unruptured IAs
• The present findings were described as supporting a potential role of atherosclerosis in IA formation

The authors concluded that prospective studies are needed to clarify the temporal relationship and evaluate whether TBI could contribute to risk stratification in patients at risk of intracranial aneurysms.

• The study design was retrospective, limiting causal inference about temporal relationships
• TBI is a non-invasive lower-limb pressure index widely used in diagnostic evaluation of peripheral artery disease
• The authors suggested TBI may have a potential role in risk stratification for intracranial aneurysms