Carotid and Vertebral Flow Velocities: Relationships With Cognitive Function in Wisconsin Native American Population

Introduction: Native American individuals are more frequently affected by cerebro-cardiovascular disease and its comorbidities, hypertension, hypercholesterolemia, diabetes, obesity, vascular brain injury, and dementias. Prevalence of Alzheimer disease and other dementias is increasing, with age being the primary risk factor. It is hypothesized that age-related changes in cardiovascular structure contribute to cognitive decline, and one proposed mechanism is reduced cerebral perfusion. We hypothesized that blood flow velocities in the common carotid artery (CCA), internal carotid artery (ICA), and vertebral arteries could be used as surrogates for cerebral perfusion and are associated with cognitive performance in our Wisconsin Native American population. Methods: 119 Native American individuals from the Oneida Nation tribe in Wisconsin enrolled in the “Stroke Prevention in the Wisconsin Native American Population” study and underwent a targeted health history, as well as blood work, clinical carotid ultrasound with B-mode, color Doppler and pulse wave Doppler, and cognitive testing using the Montreal Cognitive Assessment–First Nations (MoCA-FN). Results: Higher end diastolic velocities measured in the CCA and ICA were positively associated with higher scores on the MoCA-FN (r = 0.233, P = .012 and r = 0.198, P = .042, respectively). Distal CCA and ICA peak systolic velocities and ICA:CCA ratios were not found to correlate with cognitive performance nor did systolic or diastolic blood pressure (all P -values > .05). Associations between carotid end diastolic velocities and MoCA-FN were not statistically significant after adjustment for traditional stroke risk factors (age, gender, body mass index [BMI], systolic blood pressure, diastolic blood pressure, current smoking, physical activity, total cholesterol, low-density lipoprotein (LDL)-C, high-density lipoprotein (HDL)-C, and hemoglobin A1c), ( P > .05). The presence of plaque was also not associated with the MoCA-FN score ( P > .05). Conclusion: Future longitudinal studies are needed for this population that evaluate the composite of all risk factors and treatments targeting multiple risk factors at the same time.