Blood Pressure and Heart Rate Measures Associated With Increased Risk of Covert Brain Infarction and Worsening Leukoaraiosis in Older Adults

Abstract

Objective: In people without previous stroke, covert findings on serial magnetic resonance imaging (MRI) of incident brain infarcts and worsening leukoaraiosis are associated with increased risk for ischemic stroke and dementia. We evaluated whether various measures of blood pressure (BP) and heart rate are associated with these MRI findings.

Approach and results: In the CHS (Cardiovascular Health Study), a longitudinal cohort study of older adults, we used relative risk regression to assess the associations of mean, variability, and trend in systolic BP, diastolic BP, and heart rate measured at 4 annual clinic visits between 2 brain MRIs with incident covert brain infarction and worsening white matter grade (using a 10-point scale to characterize leukoaraiosis). We included participants who had both brain MRIs, no stroke before the follow-up MRI, and no change in antihypertensive medication status during follow-up. Among 878 eligible participants, incident covert brain infarction occurred in 15% and worsening white matter grade in 27%. Mean systolic BP was associated with increased risk for incident covert brain infarction (relative risk per 10 mm Hg, 1.28; 95% confidence interval, 1.12-1.47), and mean diastolic BP was associated with increased risk for worsening white matter grade (relative risk per 10 mm Hg, 1.45; 95% confidence interval, 1.24-1.69). These findings persisted in secondary and sensitivity analyses.

Conclusions: Elevated mean systolic BP is associated with increased risk for covert brain infarction, and elevated mean diastolic BP is associated with increased risk for worsening leukoaraiosis. These findings reinforce the importance of hypertension in the development of silent cerebrovascular diseases, but the pathophysiologic relationships to BP for each may differ.

Keywords: blood pressure; heart rate; hypertension; leukoaraiosis; risk factors.

Figure 1. Flow chart of participants

CHS = Cardiovascular Health Study, CAD = coronary artery disease, CHF = congestive heart failure, AF = atrial fibrillation, MRI = magnetic resonance imaging, WMG = white matter grade, ARB = angiotensin receptor blocker.

Figure 2. Incident covert brain infarcts (CBI) and white matter grade (WMG) on the follow-up MRI

A. Incident CBI B. WMG C. Change in WMG (A) Distribution of number of incident CBI on the follow-up MRI. (B) Distribution of WMG on the follow-up MRI. (C) Distribution of changes in WMG on the follow-up MRI.

Figure 2. Incident covert brain infarcts (CBI) and white matter grade (WMG) on the follow-up MRI

A. Incident CBI B. WMG C. Change in WMG (A) Distribution of number of incident CBI on the follow-up MRI. (B) Distribution of WMG on the follow-up MRI. (C) Distribution of changes in WMG on the follow-up MRI.

Figure 2. Incident covert brain infarcts (CBI) and white matter grade (WMG) on the follow-up MRI

A. Incident CBI B. WMG C. Change in WMG (A) Distribution of number of incident CBI on the follow-up MRI. (B) Distribution of WMG on the follow-up MRI. (C) Distribution of changes in WMG on the follow-up MRI.