Cognitive impairment and neurovascular function in patients with severe steno-occlusive disease of a main cerebral artery

Patients with severe steno-occlusive disease of a main cerebral artery may demonstrate cognitive impairment without identification of causative lesions on magnetic resonance imaging. We investigated whether cognitive impairment in these patients is associated with regional cerebral blood flow (rCBF), leukoaraiosis, risk factors of atherosclerosis and cerebrovascular reserve (CVR), which shows so-called clinical neurovascular function.

In 65 patients with severe steno-occlusive disease of an internal carotid artery or a middle cerebral artery (MCA) and no cerebral infarction (CI), we examined cognitive function with COGNISTAT, grades of leukoaraiosis, and CBF and CVR as calculated by iodine-123-N-isopropyl-p-iodoamphetamine single photon emission computed tomography and blood data. We compared such values of the left and right sided diseases. rCBF and CVR on the affected side were compared to other side.

Logistic regression analysis revealed that CVR correlated with cognitive impairment. There was no significant difference in rCBF, CVR, or COGNISTAT score when comparing the left and right sided diseases. There were good correlations between CBF or CVR of the ipsilateral MCA area and ipsilateral and contralateral other areas.

Cognitive impairment is associated with CVR in the whole brain. Nonselective widespread neurovascular mild dysfunction can be a reason for cognitive impairment in patients with severe steno-occlusive disease of a main cerebral artery and no CI.