Cerebral hemodynamics and cognitive performance in bilateral asymptomatic carotid stenosis.

OBJECTIVES: To evaluate cognitive performance in subjects with bilateral asymptomatic carotid stenosis (B-ACS) compared to subjects with unilateral ACS and to subjects with no carotid stenosis (CS) and to explore the relationship between cognitive performance and cerebral hemodynamics status in B-ACS.
METHODS: The neuropsychological investigation included phonemic (ph) and categorical (ca) Verbal Fluency (VF) tests for exploring the left brain functions and Colored Progressive Matrices (CPM) and Complex Figure Copy Test (CFCT) for the right brain. Cerebral hemodynamics status was assessed using the transcranial Doppler-based breath-holding index test.
RESULTS: A total of 333 subjects were included: 127 B-ACS, 73/77 left/right unilateral ACS, 56 no CS, mean age 70 ± 3.78 years, 65 male. Subjects with B-ACS and subjects with unilateral ACS showed significantly lower scores in all cognitive tests compared to subjects with no CS (p < 0.05). Subjects with B-ACS with left impaired hemodynamics status showed a significantly reduced ph-VF score, from 13.4 (95% confidence interval [CI] 11.2-15.8) to 7.5 (95% CI 5.4-9.7), and a reduced ca-VF score, from 19.7 (95% CI 18.1-24.1) to 10.8 (95% CI 9.5-15.1), compared to subjects with no CS. Similarly, impaired cerebral hemodynamics in the right side was associated with a significantly reduced CPM score, from an estimated mean of 34.2 (95% CI 29.8-35.4) to 24.6 (95% CI 20.2-25.8), and CFCT score from 37.0 (95% CI 32.0-37.4) to 27.1 (95% CI 23.3-28.7). All comparisons were p < 0.05.
CONCLUSION: Subjects with B-ACS and subjects with unilateral ACS are more likely to have cognitive dysfunction compared to subjects with no CS. There appears to be a link between cognitive dysfunction and hemodynamics impairment due to carotid stenosis.