Subcortical ischemic vascular dementia is a relatively common form of dementia. Anatomical changes of ageing in the brain arteries predispose the elderly to the effects of hypotension. Depending on their circulatory pattern, particular regions of the brain are susceptible to ischemic hypoperfusive lesions. These regions include the periventricular white matter, basal ganglia, and hippocampus. Interruption of prefrontal-basal ganglia circuits important for cognition and memory may result from these lesions. Hypotension and hypoperfusion explain the high risk for the development of cognitive impairment and vascular dementia in older patients affected by orthostatic hypotension, congestive heart failure, as well as in those undergoing surgical procedures such as hip and knee replacement and coronary artery bypass graft (CABG). Recognition of the susceptibility of elderly subjects to cerebral lesions induced by hypoperfusion should result in appropriate preventive measures and better treatment.