Visit-to-Visit Blood Pressure Variability and Carotid Artery Atherosclerosis: Heart Rate Was Not a Confounder
To the Editor:
We read the interesting recent article by Muntner et al,1 who found that increased visit-to-visit systolic blood pressure (SBP) variability was a significant predictor for all-cause mortality independently of age, sex, and average SBP. On the other hand, in the Letter to the Editor, Ben-Dov et al2 suggested that heart rate (HR) may bear on blood pressure (BP) variability. Bradycardia might be a confounder contributing to apparently increased visit-to-visit BP variability and possibly affecting outcome differences.
Recently we have reported the relationship of visit-to-visit BP variations (based on 12 visits once a month) with intima media thickness and stiffness in common carotid artery among the 201 high-risk elderly (79.9±6.4 years old; women: 75%: antihypertensive medication use: 71%) at cardiovascular disease.3 Exaggerated visit-to-visit BP fluctuations were significant indicators for carotid artery atherosclerosis and stiffness independent of average BP.3
However, impact of average HR on the relationship between visit-to-visit BP variations and carotid artery measures was not analyzed. Interestingly, average HR among 12 visits was significantly correlated with coefficient of variation SBP (r=−0.254; P<0.001), whereas that was not significantly correlated with delta SBP (r=0.062; P=0.4; Figure). In the multiple linear regression analysis, delta in SBP (P<0.001) was associated with maximum intima media thickness independent of age, sex, smoking, renin-angiotensin system inhibitor use, lower high-density lipoprotein level, average SBP, and average HR. The coefficient of variation (P<0.05) and delta (P<0.05) in SBP were associated with stiffness parameter β independent of age, smoking, lower high-density lipoprotein level, average BP, and average HR. Thus, HR might not be a confounder for the relationship between visit-to-visit BP variations and carotid artery atherosclerosis, although decreased HR might serve as an indicator for increased visit-to-visit BP variability.
Shobara City Soryo Clinic
Division of Cardiovascular Medicine
Department of Medicine
Jichi Medical University School of Medicine
Letters to the Editor will be published, if suitable, as space permits. They should not exceed 1000 words (typed double-spaced) in length and may be subject to editing or abridgment.
- © 2011 American Heart Association, Inc.
- Muntner P,
- Shimbo D,
- Tonelli M,
- Reynolds K,
- Arnett DK,
- Oparil S
- Ben-Dov IZ,
- Cahan A,
- Bursztyn M