A vascular approach to mild amnestic cognitive impairment: a pilot study

Mild cognitive impairment (MCI) is a subtle memory disorder not matching criteria for dementia. There is evidence for vascular comorbidity in several types of dementia. We hypothesized that neurovascular workup would detect a high degree of vascular disease in patients with MCI.

In cooperation with our memory clinic, patients with amnestic MCI were referred to our department for neurovascular investigation. The workup encompassed ultrasound examination with carotid duplex including Intima-Media-Thickness (IMT) measurement, and transcranial Doppler (TCD) including one-hour microemboli monitoring, cerebrovascular reactivity measurement and Bubble test. Cerebral MRI for the evaluation of vascular and white-matter lesions, brain atrophy, hippocampal volumes, and amyloid angiopathy was performed.

Ten patients were included. Vascular risk factors were present in six patients. Four patients had atherosclerotic lesions, three classified as mild, and one as moderate carotid stenosis. IMT > 1 mm was found in two patients, with a maximum IMT of 1.11 mm. None of the patients with acceptable bone window had intracranial stenosis in TCD. Vasoreactivity was pathologically low in one patient. Permanent right-left shunt was found in three patients, of which one showed spontaneous cerebral microembolism. Hippocampal volume reduction and cortical atrophy were found in four patients. Chronic ischemic changes in MRI were present in one patient, and three patients had subcortical infarctions. Cortical infarctions, microbleeds, or amyloid angiopathy were not found.

Pure amnestic MCI is probably less associated with cerebrovascular disease and may be more consistent with evolving Alzheimer's disease. However, vascular risk factors are common in these patients.