Relationships between ophthalmic artery flow direction and cognitive performance in patients with unilateral carotid artery stenosis

Background Cerebral hypoperfusion is responsible for cognitive impairment in patients with severe carotid artery stenosis (CAS). The manifestation of reversed ophthalmic artery flow (ROAF) is not uncommon in patients with CAS, suggesting a state of intensified cerebral hypoperfusion. This study aimed to examine whether the presence of ROAF can exacerbate cognitive impairment in patients with severe unilateral CAS. Methods One-hundred-and-two patients with CAS and 37 age-matched volunteers participated in this case-control study. Depending on the side of CAS and occurrences of ROAF, the patients were allocated to four groups: left CAS groups with ROAF (n = 28) or without ROAF (n = 22), and right CAS groups with ROAF (n = 26) or without ROAF (n = 26). All subjects underwent a battery of neuropsychological tests. Results All patients performed worse than the control group on most tests. No significant differences were observed between patient groups (ps > 0.05), except for inferior performance on psychomotor speed and visuospatial tests in the right ROAF group (ps < 0.03). Hierarchical regression analyses indicated strong contributions of estimated premorbid intelligence to performance on most tests (ps < 0.05). The severity of left and right CAS was distinctively associated with different functions. To a lesser extent, the severity of infarcts was also associated with impairment of psychomotor speed and some executive functions (ps < 0.05). The contributions of ROAF to performance on most tests were negligible. Conclusion Patients with unilateral CAS may present with specific cognitive impairment relevant to the ipsilateral hemispheric functions. However, the manifestation of ROAF does not necessarily imply more extensive or severe cognitive impairment.