Blood pressure variability and cardiovascular risk in the PROspective study of pravastatin in the elderly at risk (PROSPER)

Variability in blood pressure predicts cardiovascular disease in young- and middle-aged subjects, but relevant data for older individuals are sparse. We analysed data from the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER) study of 5804 participants aged 70–82 years with a history of, or risk factors for cardiovascular disease. Visit-to-visit variability in blood pressure (standard deviation) was determined using a minimum of five measurements over 1 year; an inception cohort of 4819 subjects had subsequent in-trial 3 years follow-up; longer-term follow-up (mean 7.1 years) was available for 1808 subjects. Higher systolic blood pressure variability independently predicted long-term follow-up vascular and total mortality (hazard ratio per 5 mmHg increase in standard deviation of systolic blood pressure = 1.2, 95% confidence interval 1.1–1.4; hazard ratio 1.1, 95% confidence interval 1.1–1.2, respectively). Variability in diastolic blood pressure associated with increased risk for coronary events (hazard ratio 1.5, 95% confidence interval 1.2–1.8 for each 5 mmHg increase), heart failure hospitalisation (hazard ratio 1.4, 95% confidence interval 1.1–1.8) and vascular (hazard ratio 1.4, 95% confidence interval 1.1–1.7) and total mortality (hazard ratio 1.3, 95% confidence interval 1.1–1.5), all in long-term follow-up. Pulse pressure variability was associated with increased stroke risk (hazard ratio 1.2, 95% confidence interval 1.0–1.4 for each 5 mmHg increase), vascular mortality (hazard ratio 1.2, 95% confidence interval 1.0–1.3) and total mortality (hazard ratio 1.1, 95% confidence interval 1.0–1.2), all in long-term follow-up. All associations were independent of respective mean blood pressure levels, age, gender, in-trial treatment group (pravastatin or placebo) and prior vascular disease and cardiovascular disease risk factors. Our observations suggest variability in diastolic blood pressure is more strongly associated with vascular or total mortality than is systolic pressure variability in older high-risk subjects

Association between different measurements of blood pressure variability by ABP monitoring and ankle-brachial index

<p>Abstract</p> <p>Background</p> <p>Blood pressure (BP) variability has been associated with cardiovascular outcomes, but there is no consensus about the more effective method to measure it by ambulatory blood pressure monitoring (ABPM). We evaluated the association between three different methods to estimate BP variability by ABPM and the ankle brachial index (ABI).</p> <p>Methods and Results</p> <p>In a cross-sectional study of patients with hypertension, BP variability was estimated by the time rate index (the first derivative of SBP over time), standard deviation (SD) of 24-hour SBP; and coefficient of variability of 24-hour SBP. ABI was measured with a doppler probe. The sample included 425 patients with a mean age of 57 ± 12 years, being 69.2% women, 26.1% current smokers and 22.1% diabetics. Abnormal ABI (≤ 0.90 or ≥ 1.40) was present in 58 patients. The time rate index was 0.516 ± 0.146 mmHg/min in patients with abnormal ABI versus 0.476 ± 0.124 mmHg/min in patients with normal ABI (P = 0.007). In a logistic regression model the time rate index was associated with ABI, regardless of age (OR = 6.9, 95% CI = 1.1- 42.1; P = 0.04). In a multiple linear regression model, adjusting for age, SBP and diabetes, the time rate index was strongly associated with ABI (P < 0.01). None of the other indexes of BP variability were associated with ABI in univariate and multivariate analyses.</p> <p>Conclusion</p> <p>Time rate index is a sensible method to measure BP variability by ABPM. Its performance for risk stratification of patients with hypertension should be explored in longitudinal studies.</p

Broadband spectral analysis of blood pressure and heart rate variability in very elderly subjects

Systolic blood pressure (SEP) variability is increased and R-R interval variability is reduced in the elderly. Little is known, however, about how SEP and R-R interval variabilities change in the very elderly. More important, however, it is not known which frequency components of SEP and R-R interval variability are affected significantly. We addressed this issue in subjects older than 70 years by broadband spectral analysis, which allows all variability components from the lowest to the highest frequency to be considered. In 20 very elderly normotensive subjects (mean+/-SD age, 78.1+/-6.8 years) and 28 normotensive adult subjects (36.1+/-7.1 years), noninvasive finger blood pressure and R-R intervals were recorded continuously for 30 minutes in the supine position and 15 minutes in the upright position. SEP and R-R interval power spectral densities were computed over the entire frequency region between 0.005 Hz (0.007 Hz in the upright position) and 0.5 Hz. Overall SEP variability (SD) was greater and overall R-R interval variability was less in very old subjects than in adult subjects. All spectral R-R interval powers were reduced significantly in very elderly individuals. The spectral SEP powers were greater in the very elderly group than in the adult group only in the very-low-frequency range (<0.04 Hz). This was true in the supine and the standing positions. With subjects in the standing position, the shape of the broadband spectra differed in the very old and adult subjects because in the former group the increase in SEP and R-R interval power around 0.1 Hz that was seen in the latter was blunted. Therefore, in very elderly subjects a reduction in overall R-R interval variability is accounted for by a reduction in all of its frequency components. The accompanying increase in overall BP variability, however, results from a nonhomogeneous behavior of its frequency components, which consists of an increase in the very low frequency and a concomitant reduction in the higher frequency powers. The mechanisms responsible for these changes may be complex, but at least they may in part reflect the baroreflex impairment and autonomic dysfunction that characterize aging

BETA-ADRENERGIC BLOCKING TREATMENT AND 24-HOUR BAROREFLEX SENSITIVITY IN ESSENTIAL HYPERTENSIVE PATIENTS

We dynamically evaluated the effects of beta-blockade on the sensitivity of arterial baroreflex control of heart rate in 10 mild or moderate essential hypertensive patients in whom blood pressure was recorded intra-arterially for 24 hours in ambulatory conditions. Twenty-four-hour baroreflex sensitivity was assessed by both (1) a time-domain approach based on the calculation of the slope of the regression line between linearly related progressive increases in systolic blood pressure and pulse interval (+PI/+SBP sequences) and decreases in systolic blood pressure and pulse interval (-PI/-SBP sequences) and (2) a frequency-domain approach, ie, the ratio between the spectral powers of pulse interval and systolic blood pressure around 0.1 Hz (alpha coefficient). Data were obtained before and after 1 month of administration of either acebutolol (n=5) or labetalol (n=5). Before treatment, the 24-hour average slopes of the +PI/+SBP and -PI/-SBP sequences were 4.36 +/- 0.32 and 4.05 +/- 0.27 ms/mm Hg, respectively, while the alpha coefficient was 7.78 +/- 0.7 ms/mm Hg. After beta-blockade, these values were increased by 25.3 +/- 6.8%, 25.0 +/- 8.0%, and 32.1 +/- 9.3%, respectively (P<.01 for all values). Thus, beta-blockers potentiate baroreflex sensitivity in daily life. Time-domain and frequency-domain methods yielded superimposable results in dynamically evaluating 24-hour baroreflex sensitivity and its changes after beta-blockade