Ambulatory blood pressure — not the doctor’s office blood pressure — can best predict the progression of small vessel brain disease and the decline of cognitive function in older people, according to a new study in Circulation: Journal of the American Heart Association. Ambulatory blood pressure is measured by monitoring blood pressure at regular intervals using a special recording device under normal living and working conditions. Clinical or in-office blood pressure is taken in a healthcare provider’s office. “This study showed for the first time in an older population that blood pressure measured over a 24-hour period was associated with the progression of vascular brain disease, whereas the typical office blood pressure was not,” said William B. White, M.D., senior author of the study and professor of hypertension and clinical pharmacology in the Calhoun Cardiology Center at the University of Connecticut School of Medicine in Farmington. To determine the effect blood pressure had on the progression of brain disease, researchers examined the change in blood pressure and volume of white matter hyperintensities (WMH) in the brain at baseline and after two years. White matter hyperintensities are a sign of small vessel brain damage that can be detected using an MRI. In addition to looking for WMH, researchers measured cognitive ability and physical mobility over the two-year time period. Previous studies by the authors and other researchers have shown that increased WMH is associated with cognitive decline. A worsening in ambulatory blood pressure was associated with an increase in WMH and a decrease in cognitive and mobility functions.If medical professionals target average ambulatory blood pressure, it could reduce the progression of small vessel brain disease, researchers said. “Interventional studies underway can determine the appropriate level of ambulatory systolic blood pressure for both home and office to prevent the accumulation of cerebrovascular disease in older people,” White said. The two-year study included 72 patients, average age 82. For the group, there were no major changes in body weight, clinical or ambulatory blood pressure during the study, and only three patients had severe medical problems, including the development of stroke, heart failure or valvular disease. Researchers reported:
- No relationship between clinical blood pressure and WMH.
- The average volume of WMH, when adjusted for age and “bad” LDL cholesterol, increased significantly over two years from 13.9 ml to 20.5 ml.
- Three of the four mobility measures and all of the cognitive measures were significantly related to WMH volume at two years.
“The results of this cohort study mean that for older people who aim to stay as functional as possible during advancing age, their blood pressure averaged out of the office, rather than in the office, might be the most important to target and treat,” White said. Co-authors are Leslie Wolfson, M.D.; Dorothy B. Wakefield, M.S.; Charles B. Hall, Ph.D.; Patrick Campbell, M.D.; Nicola Moscufo, Ph.D.; Julia Schmidt, B.S.; Richard F. Kaplan, Ph.D.; Godfrey Pearlson, M.D.; and Charles R. Guttmann, M.D. Author disclosures are on the manuscript. The National Institutes of Health funded the study.