The risk factors of old silent brain infarctions in carotid artery stenosis

Background and purpose This study aims to investigate the risk factors of old ipsilateral silent brain infarctions (iSBIs) in patients with internal carotid artery (ICA) stenosis. Methods Consecutive patients with unilateral ICA stenosis ≥ 50% or occlusion were retrospectively enrolled. Old iSBIs were assessed on magnetic resonance imaging. Baseline characteristics and imaging features were compared between patients with and without iSBIs. Multivariable regression analysis was conducted to identify independent risk factors of iSBIs. Results We enrolled 274 patients with unilateral ICA stenosis ≥ 50% or occlusion. One hundred thirty-three patients had iSBIs to stenosed ICA (48.54%). One hundred thirty-seven patients had recent brain infarction on either side (50.0%). The patients with iSBIs had a lower level of high-density lipoprotein [ OR 0.60, 95% CI (0.36–0.96), P = 0.045], higher prevalence of irregular/ulcer plaque [ OR 10.71, 95% CI (4.60–24.95), P < 0.0001], and incompleteness of circle of Willis [ OR 0.27, 95% CI (0.16–0.45), P < 0.0001] in all enrolled patients. In the patients without recent infarction on either side, lower level of high-density lipoprotein [ OR 0.42, 95% CI (0.27–0.88), P = 0.031], higher prevalence of irregular/ulcer plaque [ OR 12.73, 95% CI (4.13–39.22), P < 0.0001] and incompleteness of circle of Willis [ OR 0.24, 95% CI (0.11–0.50), P = 0.004] were independently associated with iSBIs. The results were similar in ICA stenosis patients with recent brain infarction on either side. Conclusion In patients with carotid stenosis, incompleteness of circle of Willis, irregular/ulcer plaque, and lower level of high-density lipoprotein were independently associated with old iSBIs.