Cerebral blood flow measurement by PET in hypertensive subjects as a marker of cognitive decline.

Recent epidemiological studies have shown that hypertension is a significant risk factor for Alzheimer's disease (AD). Cerebral small vessel disease (CSVD) including silent cerebral infarction and white matter lesions could represent hypertensive target organ damage in the brain and may be reliable predictors for incident dementia. However, there have been few measures to classify those patients with CSVD who are at high risk for cognitive decline and dementia. Although cerebral hypoperfusion is central to the vascular hypothesis of AD, there have been no studies linking cerebral blood flow (CBF) and future cognitive decline. Using positron emission tomography, we have demonstrated a moderate association between CBF under baseline conditions and cognitive decline during a 3-year follow-up study in 27 hypertensive patients (r=0.59, P=0.001). Findings from randomized clinical trials together with our results suggest that the preservation or improvement of CBF by anti-hypertensive treatment might be effective for the prevention of cognitive decline and dementia, especially in hypertensive patients with CSVD.