By Will Boggs, MD
NEW YORK (Reuters Health) – Systolic BP variability in midlife may lead to the development of brain white matter lesions (WMLs) and ventricular atrophy in late life, according to a report in the January issue of Stroke: Journal of the American Heart Association.
Systolic BP variability has previously been linked to CHD, the authors explain, but BP variability has not been examined as a contributor to the development of WMLs.
Dr. Richard J. Havlik, from the National Institute on Aging in Bethesda, Maryland, and colleagues used data from 575 male participants in the Honolulu-Asia Aging Study, a long-term longitudinal study examining the effect of midlife cardiovascular and other risk factors on late-life outcomes of brain aging, to explore the influence of blood pressure variability on the prevalence of brain white matter lesions.
About one in six subjects (18.4%) showed WMLs, and nearly one fourth (23%) had ventricular atrophy, the report indicates. Systolic BP variability (measured as the mean squared error, or variance, from a regression estimate) averaged 92 mm Hg and ranged from 1 to 896 mm Hg.
The rate of increase in systolic BP with age was associated with increased numbers of WMLs, the authors report, though midlife mean systolic BP and BP treatment were not associated with WMLs.
"We expected to find differences between the treated and untreated groups," Dr. Havlik told Reuters Health. "However, we did not."
The upper 3 quintiles of systolic BP variability, however, were elevated in risk for WMLs, the researchers note, and extreme variability (that is, the highest quintile compared with the lowest quintile) was associated with cerebral atrophy.
Elevated systolic BP 1 to 3 years before the magnetic resonance imaging (MRI) was also associated with a doubling of the prevalence of WMLs, but not with cerebral atrophy, the investigators say.
WMLs and cerebral atrophy were not related to diastolic BP variability, pulse pressure, or heart rate variability, the report indicates.
"Because further epidemiological and animal studies are indicated to clarify the reported relationships, the practical clinical ramifications are not clear at this time," the authors conclude.
"We would hope that smoothing the BP course would reduce the WMLs, but we are not sure," Dr. Havlik said. "It makes sense anyway to try to avoid extreme BP swings due to over or under treating with BP medications."
Based on these findings, Dr. Havlik recommends that physicians "should be more sensitive to patients with blood pressure lability and attempt to minimize [it] with careful treatment."
"In our research on late-life problems such as dementia, we are impressed that midlife risk factors are being identified with relationships over many years," he added. "So it will be important…to follow this line of research for hopefully practical recommendations in the future."