RESUMO
Patients with carotid occlusive disease express altered hemodynamics in the post-occlusive vasculature and lesions commonly attributed to cerebral small vessel disease (SVD). We addressed the question if cerebral perforating artery flow measures, using a novel 7T MRI technique, are altered and related to SVD lesion burden in patients with carotid occlusive disease. 21 patients were included with a uni- (18) or bilateral (3) carotid occlusion (64±7 years) and 19 controls (65±10 years). Mean flow velocity and pulsatility in the perforating arteries in the semi-oval center (CSO) and basal ganglia (BG), measured with a 2D phase contrast 7T MRI sequence, were compared between patients and controls, and between hemispheres in patients with unilateral carotid occlusive disease. In patients, relations were assessed between perforating artery flow measures and SVD burden score and white matter hyperintensity (WMH) volume. CSO perforating artery flow velocity was lower in patients than controls, albeit non-significant (mean difference [95% confidence interval] 0.08 cm/s [0.00-0.16]; p = 0.053), but pulsatility was similar (0.07 [-0.04-0.18]; p = 0.23). BG flow velocity and pulsatility did not differ between patients and controls (velocity = 0.28 cm/s [-0.32-0.88]; p = 0.34; pulsatility = 0.00 [-0.10-0.11]; p = 0.97). Patients with unilateral carotid occlusive disease showed no significant interhemispheric flow differences. Though non-significant, within patients lower CSO (p = 0.06) and BG (p = 0.11) flow velocity related to larger WMH volume. Our findings suggest that carotid occlusive disease may be associated with abnormal cerebral perforating artery flow and that this relates to SVD lesion burden in these patients, although our observations need corroboration in larger study populations.
RESUMO
INTRODUCTION: Patients with complete occlusion of the internal carotid artery (CAO) are vulnerable to cerebral hypoperfusion. Since cerebral hypoperfusion is associated with accelerated cognitive decline, patients with CAO may have an increased risk of cognitive impairment. We aimed to assess the prevalence and profile of cognitive impairment in patients with CAO and to explore the relation between hemodynamic impairment and cognitive functioning. METHODS: We systematically searched Medline and EMBASE for studies including patients with symptomatic or asymptomatic CAO subjected to cognitive testing that were published between 1980 and 2017. We did not include patients with carotid stenosis. We obtained data on type of study, patient characteristics, cerebral imaging and neuropsychological testing. In addition, we extracted data on potential causes of systemic hemodynamic impairment and the presence and stage of cerebral hemodynamic impairment. We assessed methodological quality of included studies with the Newcastle-Ottawa Scale. RESULTS: We found eight studies comprising 244 patients (mean age 61â¯years, 76% male, 93% symptomatic CAO). The proportion of patients with cognitive impairment ranged from 54 to 71% in four studies; in the other four studies patients with CAO performed worse on cognitive testing than controls, but results were not quantified. Impairment was reported in all cognitive domains. We found no data on the association between systemic hemodynamic impairment and cognitive functioning. Studies that assessed whether cerebral hemodynamic impairment was associated with cognitive functioning showed conflicting results. CONCLUSION: In patients with CAO, cognitive impairment is present in about half to two-thirds of patients and is not restricted to specific cognitive domains. The effect of systemic and cerebral hemodynamic impairment on cognitive functioning in patients with CAO deserves further study.
