Patients with Ocular Ischaemic Events Have Greater Cerebral White Matter Hyperintensity Volume than Asymptomatic Patients Undergoing Carotid Revascularisation

Abstract

Objective: Carotid artery stenosis may cause ocular ischaemic events (OIE) due to thrombo-embolic events or reduced perfusion to the ophthalmic arteries. While these patients have a lower risk of recurrent ipsilateral ischaemic events compared with patients with hemispheric events, the potential relationship between OIE and cerebral white matter hyperintensities (WMHs), as a manifestation of small vessel disease, has not been explored. This study investigated the presence of WMHs in patients with OIE compared with asymptomatic patients with carotid artery stenosis scheduled for carotid revascularisation. Methods: A retrospective analysis of patient and pre-operative imaging data from January 2003 to February 2022 was conducted at two large tertiary referral stroke centres. The primary outcome was presence and severity of WMHs, according to the Fazekas scale score and quantitative volume measurements using fluid attenuated inversion recovery imaging of the hemisphere corresponding to the treated and non-treated arteries. Analyses were performed using logistic and linear regression. Results: A total of 203 patients (108 asymptomatic, 95 with OIE) were included. Among those with OIE, 76 experienced transient monocular vision loss, 11 had retinal artery occlusion, and eight had ocular ischaemic syndrome. Fazekas scores were comparable between asymptomatic patients and those with OIE. In both groups, WMH was more pronounced in the periventricular white matter compared with the deep white matter. Multivariable linear regression analysis adjusted for patient demographics, cerebrovascular risk factors, and silent brain infarcts further revealed that patients with OIE had statistically significantly higher log transformed WMH volumes than asymptomatic patients in both the hemisphere corresponding to the treated artery (β 0.62, 95% confidence interval [CI] 0.05 – 1.18) and the hemisphere corresponding to the non-treated artery (β 1.04, 95% CI 0.41 – 1.67). Conclusion: Patients with OIE showed higher WMH volumes compared with asymptomatic patients. This may reflect an increased vulnerability to subclinical cerebral small vessel disease, supporting the potential role of intensified brain protective strategies, such as stricter lifestyle modification and more aggressive cardiovascular risk management, in addition to the prevention of ocular ischaemia.