Home blood pressure variability and subclinical atherosclerosis in multiple vascular beds

a population-based study

Abstract

Objective: 

The mechanism by which higher blood pressure (BP) variability causes cardiovascular events remains unclear. Experimental results indicate that alterations in vessel wall tension related to BP variability may initiate atherosclerosis through oscillatory shear stress. We examined associations of home BP variability with subclinical atherosclerosis at four anatomically distinct vascular beds.

Methods: 

In a cross-sectional population-based study of 1033 Japanese (mean age, 64.0 years; men, 88.7%) without known cardiovascular disease, we defined SBP and DBP variability as variability independent of the mean (VIM) across self-measured home BP values during seven consecutive days and quantified coronary and aortic artery calcification (CAC and AAC) by computed tomography, carotid intima−media thickness (CIMT) by ultrasonography, and ankle−brachial index (ABI).

Results: 

In multivariable adjusted models including mean SBP, higher VIM of SBP was associated with CIMT greater than1.0 mm [relative risk (95% confidence interval) fourth versus first quartile, 1.71 (1.15–2.54)], AAC score greater than 0 [1.08 (1.02–1.15)], and ABI less than 1.1 [1.49 (1.12–1.97)], and linear trends were also statistically significant. However, there was no significant association between VIM of SBP and CAC score greater than 0. Meanwhile, higher VIM of DBP was associated only with AAC score greater than 0. The associations were similar when modeling subclinical atherosclerosis severity as continuous outcomes and were consistent across subgroups based on demographics, behavioural, and cardiovascular risk factors.

Conclusion: 

Higher variability in home BP, particularly in home SBP, was associated with greater carotid, aortic, and peripheral but not coronary atherosclerosis burdens independent of the mean home BP.