Abstract 15207: Endothelial Function in Postmenopausal Women with High Nighttime Systolic Blood Pressure
Background: Nighttime systolic blood pressure (SBP) is more predictive of adverse cardiovascular events than daytime SBP and recent evidence suggests that this relationship may be stronger for women than men. Although higher daytime clinic SBP is associated with vascular endothelial dysfunction, less is known about the relationship of nighttime SBP to endothelial function. We hypothesized that higher nighttime SBP would be associated with impaired endothelial function.
Methods: Postmenopausal women underwent 24-hour ambulatory blood pressure monitoring and noninvasive assessment of endothelial function (brachial artery flow-mediated dilation; FMD). The nighttime sleep period was determined by participant diary and actigraphy.
Results: The sample consisted of 96 postmenopausal women with a mean (±SD) age of 66±7 years, body mass index of 28.4±4.8 kg/m2, clinic BP of 138±17/68±11 mmHg, and nighttime SBP of 114±13 mmHg. Coronary artery disease and hypertension were present in 49% and 53% of women respectively. Mean FMD (percent change from baseline) was 4.5±4.1%. FMD was inversely correlated with nighttime SBP (r=-.42, p<.0001). This correlation remained significant (r=-.31, p=.003) after controlling for baseline artery diameter, age and daytime SBP. When participants were divided into those with elevated nighttime SBP (>120 mmHg; n=33) and those with normal nighttime SBP (≤120 mmHg, n=63), FMD was significantly lower in women with elevated nighttime SBP (mean±SE: 2.4±0.7 vs 5.6±0.5 %; p<.001). This difference remained significant (3.0±0.7 vs 5.4±0.5 %; p=.017) following adjustment for baseline artery diameter, age, and daytime SBP.
Conclusion: Elevated nighttime SBP is associated with impaired endothelial function among postmenopausal women. Endothelial dysfunction may contribute to a heightened risk of adverse clinical outcomes in postmenopausal women with high nighttime SBP.
- © 2011 by American Heart Association, Inc.