Moderate Hypertension Linked to Adverse Brain Changes


Major Finding: A significant correlation was found between 24-hour ambulatory systolic hypertension, brain damage, and functional and cognitive impairment in elderly people. Each 1–mm Hg rise in systolic pressure over a 2-year period linked with an average 0.04% increased brain volume of white matter hyperintensity.

Data Source: Two-year follow-up study of 72 people aged 75-89 years (average age, 82 at baseline) who were normotensive or mildly hypertensive at entry.

Disclosures: Dr. White said that he has been a consultant to the Forest Research Institute and has received research grants from Novartis.

NEW ORLEANS – Elderly people with modestly elevated systolic blood pressures showed significant declines in their mobility and cognition, and concurrent significant increases in brain damage, during 2 years of follow-up in a small study.

These correlations suggest a possible new reason to control blood pressure in the elderly, Dr. William B. White said at the meeting.

“These data support an interventional trial evaluating different thresholds of ambulatory systolic blood pressure for preventing white matter progression and functional decline in older people,” said Dr. White, professor of medicine and chief of the division of hypertension and clinical pharmacology at the University of Connecticut in Farmington.

He plans to compare target systolic blood pressures of 145 and 130 mm Hg, he said in an interview. “If you can intervene in patients with early-onset white matter disease and prevent progression, then you will do these people a big favor. I don't think we will see regression [of white matter damage], just prevention of it getting worse. This is the first study I know of to longitudinally compare ambulatory blood pressure with both white matter hyperintensity and functional decline in older people. Blood pressure turned out to be the most important” determinant of declines in cognition and mobility and in an MRI measure of brain damage, “and blood pressure is something where we can intervene,” he said.

“Hypertension specialists think about the burden [of hypertension] on the heart and the kidney, but they don't think about the chronic burden on the brain,” said Dr. C. Venkata S. Ram, professor of medicine at the University of Texas Southwestern Medical Center in Dallas. “Chronic hypertension can lead to significant morphologic and physiologic dysfunction. Many patients diagnosed with Alzheimer's disease probably had poorly controlled hypertension over their lifetime.”

Dr. White and his associates enrolled 72 people aged 75-89 with various degrees of mobility and cognitive impairment who underwent blood pressure, cognitive, mobility, and MRI brain assessments at entry and 24 months later. At baseline, their age averaged 82 years, their 24-hour ambulatory blood pressure averaged 126/66 mm Hg, and their average amount of brain white matter hyperintensity, a marker of brain damage, was 1% of their total brain volume. Two years later, their average ambulatory blood pressure stood at 131/67 mm Hg. At both times, about 70% of patients received antihypertensive medication.

When the researchers compared the findings at the two measurement times, they found that for each 1% increase in the volume of white matter hyperintensity, subjects showed an average 0.31-second decrease in their walk time and a 33-millisecond increase in their simple reaction time on cognitive testing. In addition, for each 1–mm Hg increase in 24-hour systolic blood pressure over the 2-year period between measurements, the subjects had an average 0.04% increase in their volume of white matter hypertrophy.

In a different analysis, Dr. White and his associates divided the 72 people into tertiles based on their 24-hour systolic blood pressure at their 2-year assessment. The top and bottom tertiles had average systolic pressures of 144 and 117 mm Hg. The top tertile showed a significantly larger increase in white matter hyperintensity volume over the 2 years of follow-up, a significantly longer 8-foot walk time, a significantly slower walking speed, and nonsignificant trend toward poorer results on cognition tests.

Also notable in the findings was that a modest level of systolic hypertension in the highest tertile linked with significant changes over the 2-year period. “The people only averaged 144 mm Hg. That's not so bad, but they had progression,” Dr. White said.

Blood pressure was the most important determinant of declines in cognition and mobility.

Source DR. WHITE

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