Hypertension, raised blood pressure, is very damaging to tissues and organ function throughout the body. It significantly increases the pace at which capillaries rupture, leading to small areas of cell death. The loss of function adds up, particularly in the brain, where this damage shows up as white matter lesions in imaging. The study here illustrates the damage done, and reinforces the message that control of blood pressure is very important for long term health. It has already been shown to reduce mortality, and the work here gives some insight into the mechanisms by which this reduction occurs.
It's been estimated that approximately two-thirds of people over the age of 75 may have damaged small blood vessels in the brain which are visible as bright white lesions on brain imaging. Prior research evidence has linked increased amounts of these white matter lesions in the brain with cognitive decline, limited mobility such as a slower walking speed, increased incidence of falls, and even increased stroke risk.
A clinical trial, followed 199 hypertension patients 75 years of age and older for 3 years. Throughout that time, researchers tracked the potential benefits of using an intensive anti-hypertensive medication treatment regimen to garner a 24-hour systolic blood pressure target of less than 130 mmHg compared to standard control (approximately 145 mmHg). As part of the INFINITY (Intensive Versus Standard Ambulatory Blood Pressure Lowering to Prevent Functional Decline In the Elderly) study, researchers assessed the older adults' mobility, cognitive function, their brain's white matter progression with magnetic resonance imaging (MRI), and tracked the occurrence of any adverse events.
While the researchers did not identify any significant differences in cognitive outcomes or walking speed between the two study groups, they did observe a significant reduction in the accumulation of brain white matter disease in those receiving the intensive treatment for blood pressure control. In fact, after three years, the accrual of white matter lesions in the brain were reduced by up to 40% in the those patients receiving the intensive blood pressure therapy compared to those who were on standard therapy. Further, study participants on the intensive therapy had a lower rate of cardiovascular events including heart attack, stroke, and hospitalization from heart failure than those on standard therapy.