Hypertension, raised blood pressure due to age-related dysfunction of blood vessels, is an important process in aging. It is one of the more important ways in which low-level biochemical damage and cellular malfunctioning is converted into high level structural damage to tissues. Pressure damage to the sensitive tissues of the brain, kidney, lungs, and more causes large degrees of functional loss when taking place over years. In the brain, rupture of capillaries leads to countless tiny, unnoticed strokes, each destroying a small volume of brain tissue. This slowly adds up to produce cognitive decline and dementia, one small loss at a time.
Elderly people with high blood pressure, or hypertension, who took medicine to keep their 24-hour systolic blood pressure around 130 mm Hg for three years showed significantly less accumulation of harmful brain lesions compared with those taking medicine to maintain a systolic blood pressure around 145 mm Hg, according to new research. However, the reduction in brain lesions, visible as bright white spots on a magnetic resonance imaging (MRI) scan, did not translate to a significant improvement in mobility and cognitive function. Researchers said it is likely that three years was too short a time for such benefits to become apparent.
The study, called INFINITY, is the first to demonstrate an effective way to slow the progression of cerebrovascular disease, a condition common in older adults that restricts the flow of blood to the brain. The study is also unique in its use of around-the-clock ambulatory blood pressure monitors, which measured participants' blood pressure during all activities of daily living, rather than only in the medical care environment. In addition to seeing beneficial effects in the brain, those who kept their blood pressure lower also were less likely to suffer major cardiovascular events, such as a heart attack or stroke.
"I think it's an important clinical finding, and a very hopeful one for elderly people who have vascular disease of the brain and hypertension. With the intensive 24-hour blood pressure treatment we reduced the accrual of this brain damage by 40 percent in a period of just three years. That is highly clinically significant, and I think over a longer time period intensive reduction of the ambulatory blood pressure will have a substantial impact on function in older persons, as well."