Long-term blood pressure fluctuation and cerebrovascular disease in an elderly cohort

Abstract

Background: The importance of subclinical cerebrovascular disease in the elderly is increasingly recognized, but its determinants have not been fully explicated. Elevated blood pressure (BP) and fluctuation in BP may lead to cerebrovascular disease through ischemic changes and compromised cerebral autoregulation.

Objective: To determine the association of BP and long-term fluctuation in BP with cerebrovascular disease.

Design: A community-based epidemiological study of older adults from northern Manhattan.

Setting: The Washington Heights-Inwood Columbia Aging Project.

Participants: A total of 686 nondemented older adults who had BP measurements during 3 study visits at 24-month intervals and underwent structural magnetic resonance imaging (corresponding temporally with the third assessment). We derived the mean (SD) of the mean BP for each participant during the 3 intervals and divided the participants into 4 groups defined as below or above the group median (<or=96.48 or >96.48 mm Hg) and further subdivided them as below or above the median SD (<or=7.21 or >7.21 mm Hg). This scheme yielded 4 groups representing the full range of BPs and fluctuations in BP.

Main outcome measures: Differences in white matter hyperintensity (WMH) volume and presence of brain infarctions across groups.

Results: White matter hyperintensity volume increased across the 4 groups in a linear manner, with the lowest WMH volume in the lowest mean/lowest SD group and the highest WMH volume in the highest mean/highest SD group (F(3,610) = 3.52, P = .02). Frequency of infarction also increased monotonically across groups (from 22% to 41%, P for trend = .004).

Conclusions: Compared with individuals with low BP and low fluctuations in BP, the risk of cerebrovascular disease increased with higher BP and BP fluctuations. Given that cerebrovascular disease is associated with disability, these findings suggest that interventions should focus on long-term fluctuating BP and elevated BP.

Figure 1

Differences in log transformed relative WMH volume across blood pressure groups. There was a significant monotonic trend across blood pressure groups (p=.015). Mean values are adjusted for age, sex, and treatment status. Group 1 contains participants with lower mean BP (<96.48 mmHg) and lower fluctuation (SD < 7.21 mmHg); group 2comprises participants with lower mean BP (<96.48 mmHg) and higher fluctuation (SD < 7.21 mmHg); group 3 comprises participants with higher mean BP (>96.48 mmHg) and lower fluctuation (SD < 7.21 mmHg); and group 4 comprises participants with higher mean BP (>96.48 mmHg) and higher fluctuation (SD < 7.21 mmHg).

Figure 2

Percentage of participants with radiological infarct across blood pressure groups. There was a significant monotonic trend across groups (p=.004).