ABSTRACT NUMBER: ESOC2026A733 ASSOCIATION OF BRANCH ATHEROMATOUS DISEASE WITH LARGE ARTERY PHENOTYPES AND SMALL VESSEL DISEASE IN A WESTERN COHORT

Abstract Background and aims Larger lacunar strokes are often attributed to branch atheromatous disease (BAD), especially in Asian populations. We aimed to classify BAD in European patients, and explored its association with large artery phenotypes and small vessel disease (SVD). Methods We recruited patients prospectively with acute clinical lacunar and mild cortical ischaemic strokes. We defined BAD using two common criteria: 1) slice/shape: tubular-like lesions coronally or axial thickness >15mm; 2) size: >20mm within or >15mm after one month. We assessed associations between BAD and large cranial artery stenosis or widening, and SVD markers using adjusted logistic regression. Results Amongst 229 participants, 114 with lacunar stroke, 42/114 (criteria1) and 21/114 (criteria2) had BAD (kappa=0.439). Lacunar-BAD had fewer lacunes (criteria1: adjusted odds ratio (aOR) 0.839, 95%CI 0.718-0.980, p=0.027; criteria2: aOR 0.717, 0.546-0.943, p=0.017), lower SVD score (criteria1: aOR 0.522, 0.327-0.833, p=0.007; criteria2: aOR 0.405, 0.185-0.887, p=0.024), and lower white matter hyperintensity volumes (criteria1 only (p<0.001)) compared to lacunar-non-BAD strokes. Neither large artery stenosis nor widening differed between lacunar-BAD and lacunar-non-BAD stroke (any stenosis 16.7% vs 22.9%; basilar widening 21.4% vs 23.6%) , all p>0.05). Amongst 42/229 lacunar-BAD (criteria1), basilar artery diameter was wider (aOR 1.843, 1.085-3.129, p=0.024) and amongst 21/229 lacunar-BAD (criteria2), middle cerebral artery diameter was smaller (aOR 0.107, 0.017-0.661, p=0.016) than in all non-BAD strokes . Conclusions BAD occurs in Europeans, but current definitions are very inconsistent. Lacunar-BAD had fewer SVD markers but similar associations with large artery widening and few stenoses as in lacunar-non-BAD strokes, suggesting a non-atheromatous etiology of BAD. Conflict of interest All authors: nothing to disclose