Relation of Blood Pressure Variability to Carotid Atherosclerosis and Carotid Artery and Left Ventricular Hypertrophy

Abstract

Abstract-The relationship of blood pressure (BP) variability to cardiovascular target-organ damage is controversial.Studies examining BP variability and left ventricular (LV) hypertrophy have been contradictory, and only limited data on the relation of BP variability to carotid atherosclerosis and carotid artery hypertrophy exist. BP variability was assessed as the standard deviation and coefficient of variation of awake and asleep pressures in 511 normotensive or untreated hypertensive subjects who underwent ambulatory BP monitoring and cardiac and carotid ultrasonography. Although the presence of focal carotid plaque was associated with an increase in ambulatory pressures and pressure variability, the differences in variability were eliminated by adjustment for age and absolute pressures. Similarly, LV mass was significantly related to BP variability, but the significance of this finding was eliminated after adjustment for important covariates. In multivariate analyses, age was the primary determinant of carotid artery cross-sectional area, with a weak but independent contribution from awake systolic and diastolic BP variability in addition to absolute pressure. BP variability was not independently related to either carotid or LV relative wall thickness, both measures of concentric remodeling. In the present study, awake BP variability was weakly but independently associated with carotid artery cross-sectional area, a measure of arterial hypertrophy. However, neither systolic nor diastolic BP variability was independently associated with carotid atherosclerotic plaque or LV mass. Key Words: blood pressure Ⅲ hypertension Ⅲ hypertrophy Ⅲ carotid arteries Ⅲ atherosclerosis B lood pressure (BP) variability is modulated by both intrinsic cyclic vasomotion and the impact of physical and mental activity 1 and is inversely related to baroreceptor reflex sensitivity, its primary determinant. 2 An increase in BP variability is additionally seen with aging and hypertension. 2,3 Whereas early studies of BP variability were based on intra-arterial recordings in selected subjects, the development of reliable, noninvasive, ambulatory BP monitoring has permitted more widespread study of its determinants and consequences. BP variability is most commonly quantified as the standard deviation (SD) of BP readings assessed during a particular activity or time period or as the coefficient of variation (CV; SD of blood pressure/mean pressure), which adjusts for the tendency of those with a higher average BP to also have a higher SD. 3,4 Two recent studies, one population based 4 and the other hospital based, 5 have suggested that an increase in BP variability (primarily manifested as an increase in daytime systolic BP variability) is associated with an increase in subsequent cardiovascular events 5 and cardiovascular mortality. 4 The mechanism of this relationship remains speculative but may involve an excess of underlying cardiovascular target-organ damage, including carotid atherosclerosis, as either a cause or a result of increase...

Relationship between birth weight and blood pressure variability in children

“…Similar results (P40.2) were seen when a coefficient of variation (equal to the standard error divided by the mean of the 24-h measurements), which allows adjustment for the positive correlation between blood pressure mean values and variability, 5 was used in the analysis.…”

“…Adult studies have assessed the variability of both systolic and diastolic blood pressure using measures such as the standard deviation of the daytime mean, 4,5,15 the standard deviation of the night time mean, 5,14 the coefficient of variation (estimated as the standard deviation divided by 100 times the mean blood pressure), 5 the difference between the average value in the top 5% of readings from the overall average for the individual, 4 intermittent standard deviations 6 and the sleep/awake ratio. 16 We used the standard deviation of the 24-h blood pressure monitoring values as a measure of the 24-h variability, which shows the spread of an individuals blood pressure readings taken over a 24-h period.…”

“…1,2 There are now a number of reports from the adult literature that increased blood pressure variability is also related to end-organ damage, although the reasons for this increased variability remain speculative. [3][4][5][6] A recent study in children found a significant association between birth weight and blood pressure variability, measured using 24-h blood pressure recordings in childhood, suggesting that the tendency to high blood pressure variability is determined, at least to some extent, in intrauterine life. 7 The investigation of blood pressure variability is complicated by the fact that blood pressure has a positive relation with variability, 5 and also that 24-h blood pressure in children is influenced by age and gender.…”

“…[3][4][5][6] A recent study in children found a significant association between birth weight and blood pressure variability, measured using 24-h blood pressure recordings in childhood, suggesting that the tendency to high blood pressure variability is determined, at least to some extent, in intrauterine life. 7 The investigation of blood pressure variability is complicated by the fact that blood pressure has a positive relation with variability, 5 and also that 24-h blood pressure in children is influenced by age and gender. 8 This present study was designed to investigate further the hypothesis that blood pressure variation in childhood may be predicted by birth weight, independently of blood pressure values, after adjusting for potential confounding factors such as age, current blood pressure, gestation and gender.…”

Blood pressure variability is significantly associated with ECG left ventricular mass in normotensive Africans: The SABPA Study

“…Conversely, in hypertensive Africans, left ventricular mass was significantly associated with office, 1-minute, 24-h, daytime and night time BP, as well as BP reactivity measurements, but there was a complete absence regarding the relationship with 24-h SBP variability. Schillaci et al 38 and Roman et al 43 also observed this lack of association in Caucasians with essential hypertension. Contradictory results have been provided over the years regarding the predictive value of BP variability, 4,8,10,14 which might be due to differences in methods, too few events or different indexes of BP variability.…”