Hypertension and Cerebral Blood Flow

The contribution of cerebrovascular disease to development of dementia in the elderly remains a perplexing and unresolved issue with direct clinical implications. In the early part of the past century, the popular notion was that some type of vascular pathology (eg, “hardening of the arteries”) was a contributing factor. Yet, the idea that cerebrovascular disease plays a significant role in Alzheimer disease (AD) and related degenerative brain disorders was dismissed by a majority of dementia researchers, because AD pathology was found to be strongly related to specific neuronal abnormalities involving β-amyloid, τ protein, and disruption of cholinergic brain systems.1,2 Yet, clinical and experimental research conducted over the past several years suggests that cerebrovascular disease may play a greater role in degenerative dementia than was previously believed.3–8 Vascular disease is associated with increased risk for AD.3,9–11 Also, many of the biochemical processes involved in AD share common mechanisms with cerebrovascular disease factors12,13 (endothelial health, oxidative stress response, insulin metabolism, etc), suggesting possible convergence of underlying neuropathological mechanisms, at least among certain patients.14 There is a compelling need for studies aimed at achieving greater understanding about the relationship between vascular disease and the development of dementia in the elderly.The diagnostic classification of vascular dementia (VaD) was developed to account for cases in which severe functional impairments could be unambiguously attributed to stroke or other well-defined vascular pathology.15 Unfortunately, the diagnosis of VaD is a clinical conundrum, because pure cases are more the exception than the rule, and also many of the cognitive and many of the clinical characteristics thought to differentiate VaD from AD (ie, stepwise progression, patchy cognitive profile, different cognitive presentations) have not held up in controlled studies.16 This diagnostic dilemma is most apparent for patients being assessed in memory disorder clinics …