Short-term Systolic Blood Pressure Variability Research Articles

More moderate-intensity physical activity and less prolonged sedentary time are associated with better very short-term systolic blood pressure variability in healthy adults.

Whole-day movement guidelines for improving health, recommend that adults engage in at least 150 min week-1 of moderate-to-vigorous aerobic physical activity and limit their sedentary time. In young adults, higher systolic blood pressure variability (BPV) is a precursor for the development of hypertension. The impact of habitual activity that comprises (inter)national guidelines on BPV is unclear. We tested the hypothesis that less habitual physical activity and greater sedentary time would be associated with larger BPV. Ninety-two normotensive participants [age: 19-38 years, body mass index (BMI): 23.6 ± 3.3 kg/m2, 44♀] wore an activPAL monitor on their thigh for 7.0 ± 0.3 days. Ten minutes of supine systolic arterial pressure was measured via finger photoplethysmography (115 ± 11 mmHg). Beat-by-beat systolic BPV was measured using the average real variability index (1.1 ± 0.6 mmHg). Relationships between habitual activity outcomes and BPV were assessed via multiple regressions adjusted for age, sex, and BMI. Moderate-intensity physical activity (average: 36 ± 19 min day-1; β = -0.010, p = 0.02) and time spent in sedentary bouts >1-h (245 ± 134 min day-1; β = 0.002, p < 0.001), but not light-intensity activity, vigorous-intensity activity, standing time, sedentary breaks, or time spent in sedentary bouts <1-h (all, p > 0.10) were predictors of systolic BPV. Higher moderate physical activity and lower prolonged sedentary time were associated with attenuated systolic BPV responses in young adults. These findings highlight the cardiovascular benefits of habitual activity among younger adults and suggest that simple strategies such as reducing long periods of uninterrupted sitting and increasing moderate-intensity physical activity may be efficacious for reducing the risk of developing or delaying the onset of hypertension.

EFFECT OF VALSARTAN/AMLODIPINE FIXED-DOSE COMBINATION THERAPY IN REDUCING BLOOD PRESSURE VARIABILITY IN CHINESE HYPERTENSIVES

Objective: To investigate the effect of valsartan/amlodipine fixed-dose combination(Val/Aml FDC) monotherapy on short-term and long-term systolic blood pressure variability(SBPV).Design and method: 980 consecutive hypertensives from 27 medical centers in China were enrolled to receive daily Val/Aml FDC. One-year SBPVs were assessed by three levels, 24-hour, weekly and monthly BPV. 24-hour Ambulatory BP monitoring (ABPM) was performed after 1-month and 6-month treatment. Home BP monitoring (HBPM) was performed weekly and monthly for each patient. Weekly SBP readings(52 visits in total) were divided into 4 groups to calculate weekly SBPV. While monthly SBP readings(12 visits in total) were divided into 2 groups. Standard deviation(SD, including weighted SD, SD-daytime and SD-nighttime), coefficient of variation(CV) and average real variability(ARV) were calculated with validated formula. Results: In 980 consecutive hypertensives, weekly SBPV, evaluated by HBPM as SD or CV, decreased significantly and progressively from the first to the last quarter, during the one-year Val/Aml FDC treatment(p for trend <0.05). Similar trend was also observed in patients with complete treatment for 52 weeks(all p < 0.05 and p for trend <0.05). As for the monthly variation, when SBPV was calculated by the first and the last 6-month HBPM, patients’ SBPV in the last 6-month was significantly lower than the readings coming from the first 6-month in the setting of SD(5.08 ± 0.22 vs 5.78 ± 0.21mmHg, p < 0.05)and CV(4.04 ± 0.17 vs 4.62 ± 0.17%, p < 0.05). But the difference in total population didn’t remain statistical significant(p = 0.0976 and p = 0.132 for SD and CV respectively). Similarly, after 6-month Val/Aml FDC treatment, daily SBPV, assessed by 24-hour ABPM, decreased significantly in all settings(all p < 0.01), only except for night-time SD setting(p = 0.22). Conclusions: After one-year treatment, Val/Aml FDC monotherapy could significantly reduced hypertensive patients’ long-term and short-term SBPV.

A8062 Effects of long-term high-salt diet on blood pressure variability in Wistar rats

Objectives: To observe the effects of long-term high-salt diet on blood pressure variability in Wistar rats. Methods: The 53 male Wistar rats were randomly divided into control group (containing 0.5% NaCl, n = 12) and 8% high-salt group (containing 8% NaCl, n = 41), Both water and food were supplied ad libitum for 24 weeks. Tail systolic blood pressure was monitored by tail-cuff artery pressure-measuring instrument, the tail artery pressure of the rats was respectively determined before the experiment (0 week), in the 3rd, 5th, 6th, 7th, 9th, 11th, 13th, 15th, 17th, 19th, 21st, 23rd, 24th week. According to the blood pressure levels, the 8% high-salt group were divided into high-salt normal blood pressure group (HSN group, n = 7) and high-salt hypertension group (HSH group, n = 34), all groups of short-term BPV and long-term BPV were calculated after the end of the experiment. Results: Compared with control group, the blood pressure, short-term systolic blood pressure variability (SBPV), short-term standard deviation of diastolic blood pressure (DSD), long-term SBPV and diastolic blood pressure variability (DBPV) were continuously increased in 8% high-salt group (P < 0.05). The long-term SBPV was increased in HSN group (P < 0.05), the blood pressure, short-term SBPV, long-term SBPV, short-term DSD, long-term DBPV were increased in HSH group (P < 0.05). Compared with HSN group, the blood pressure, long-term SBPV and long-term DBPV were increased in HSH group (P < 0.05). Conclusion: Long-term high-salt diet may induce increases the long-term SBPV, long-term DBPV, and earlier than the rise of blood pressure in high-salt hypertension group. The long-term SBPV is increased in high-salt normal blood pressure group.

Association Between Short-Term Systolic Blood Pressure Variability and Carotid Intima-Media Thickness in ELSA-Brasil Baseline.

Blood pressure (BP) is associated with carotid intima-media thickness (CIMT), but few studies have explored the association between BP variability and CIMT. We aimed to investigate this association in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) baseline. We analyzed data from 7,215 participants (56.0% women) without overt cardiovascular disease (CVD) or antihypertensive use. We included 10 BP readings in varying positions during a 6-hour visit. We defined BP variability as the SD of these readings. We performed a 2-step analysis. We first linearly regressed the CIMT values on main and all-order interaction effects of the variables age, sex, body mass index, race, diabetes diagnosis, dyslipidemia diagnosis, family history of premature CVD, smoking status, and ELSA-Brasil site, and calculated the residuals (residual CIMT). We used partial least square path analysis to investigate whether residual CIMT was associated with BP central tendency and BP variability. Systolic BP (SBP) variability was significantly associated with residual CIMT in models including the entire sample (path coefficient [PC]: 0.046; P < 0.001), and in women (PC: 0.046; P = 0.007) but not in men (PC: 0.037; P = 0.09). This loss of significance was probably due to the smaller subsample size, as PCs were not significantly different according to sex. We found a small but significant association between SBP variability and CIMT values. This was additive to the association between SBP central tendency and CIMT values, supporting a role for high short-term SBP variability in atherosclerosis.

Beneficial Effects of Paeoniflorin Enriched Extract on Blood Pressure Variability and Target Organ Damage in Spontaneously Hypertensive Rats.

Blood pressure variability (BPV) is associated with the development and progression of severe target organ damage (TOD). This study aims to evaluate the protective effect of paeoniflorin enriched extract from Radix Paeoniae Alba (PG) on BPV and TOD in spontaneously hypertensive rats (SHR). All SHR were orally treated with distilled water, metoprolol (MP, 20 mg/kg), and PG (PG-H, 90 mg/kg or PG-L, 30 mg/kg) for a single time or daily for 7 weeks. The 24-hour dynamic blood pressure was monitored and then calculated BPV including long- and short-term systolic blood pressure variability (SBPV), diastolic blood pressure variability (DBPV), mean blood pressure variability (MBPV), and heart rate variability (HRV) as well as the 24-hour-SBP, 24-hour-DBP, and 24-hour-MBP. The protective effects of PG on TOD were observed by histopathologic and biochemical detection. The results indicated that long- and short-term SBPV, DBPV, MBPV, and HRV as well as 24-hour-SBP, 24-hour-DBP, and 24-hour-MBP showed no significant changes after single-dose administration of PG and significantly decreased after administration with PG for 7 weeks. PG could also markedly improve the damage of aorta, heart, kidney, and brain. This study suggested that PG could notably reduce BPV, stabilize blood pressure, and mitigate TOD in SHR.

PP.15.02] LOWER HEART RATE VARIABILITY ASSESSED BY 24-HOUR AMBULATORY BLOOD PRESSURE MONITORING IS ASSOCIATED WITH LEFT VENTRICULAR HYPERTROPHY

Objective: To assess the association between variability of both heart rate (HR) and systolic blood pressure (SBP) with left ventricular hypertrophy (LVH) and cardiovascular risk (CR) in hypertensive patients. Design and method: We included consecutive patients who underwent 24-hr ambulatory blood pressure monitoring (ABPM) in our outpatient clinic. Short-term SBP variability (SBPV) was calculated as average real variability (ARV). Short-term HR variability (HRV) was determined as standard deviation (SD-HR), as well as by ARV. LVH was evaluated by electrocardiographic criteria (Cornell QRS voltage). European Guidelines on cardiovascular prevention were used to assess CR. Pearson test was used to evaluate bivariate correlations. Student-t test was used to compare means of quantitative variables between 1st and 4th quartile of HRV and SBPV. Multivariate analysis was used to adjust for potential confounders, including age, and therapy known to affect heart rate or blood pressure variability. P values <0.05 were considered statistically significant. Results: One hundred and sixty six patients (mean age 58.5 ± 16.1years, 52.4% female) were included. We found a significant inverse correlation between HR-ARV (but not SD-HR) and LVH (r = −0,217; p = 0,045). These results were independent of age and beta-blocker therapy. Patients within the lowest HR-ARV quartile showed increased 24 hr-SBP (134.5 ± 17.9 vs. 124.0 ± 14.8 mmHg; p = 0.007), pulse pressure (59.4 ± 16.8 vs. 49.7 ± 12.2 mmHg; p = 0.005), and LVH (18.0 ± 8.6 vs. 13.6 ± 5.5 mV; p = 0.047) compared with those in the highest HR-ARV quartile. SBPV correlated with LVH (r = 0,260; p = 0,015) and was significantly higher in patients with very high CR when compared with those with low CR (9.9 ± 2.3 vs.7.4 ± 1.8 mmHg, respectively; p < 0.001). Conclusions: Lower HR variability assessed by 24-ABPM is associated with LVH. SBP variability correlated positively with LVH and it was significantly increased in patients with the highest CR when compared to those with the lowest CR. Our findings could explain the previously reported association between reduced HR variability and poor cardiovascular risk. Larger and prospective studies are needed to ascertain whether this association is causal and potentially be reversed pharmacologically.

Blood pressure variability in controlled and uncontrolled blood pressure and its association with left ventricular hypertrophy and diastolic function.

High systolic blood pressure (SBP) variability has been associated with higher risk for target-organ damage. In a cross-sectional study done in a tertiary outpatient hypertension clinic, we compared short-term SBP variability among controlled and uncontrolled hypertensive patients and evaluated the association between higher levels of SBP variability and diastolic function and left ventricular hypertrophy (LVH). Patients were evaluated by 24-h ambulatory blood pressure monitoring and transthoracic Doppler echocardiogram. Blood pressure (BP) variability was evaluated by the time-rate index and high variability corresponded to index values in the top quartile of distribution. Echocardiographic parameters were compared in patients with and without higher BP variability within controlled and uncontrolled office BP (⩽140/90 mm Hg). The analyses included 447 patients with 58±12 years of age, 67% were women, 68% white, 43% current or previous smokers and 32% with diabetes mellitus. Among the whole sample, 137 patients had controlled and 310 uncontrolled BP. The 75th percentile cutoff points for the time-rate index were 0.502 mm Hg min(-1) and 0.576 mm Hg min(-1) for participants with controlled and uncontrolled BP, respectively. After adjustment for confounders, the time-rate index did not differ between controlled and uncontrolled patients. BP variability was not associated with LVH or diastolic function in controlled and uncontrolled BP after adjustment for 24-h SBP and age. Patients with controlled and uncontrolled BP had similar SBP variability assessed by time-rate index, which was not associated with LVH or diastolic function. These findings should be confirmed in studies with larger sample size.

Separate estimation of long- and short-term systolic blood pressure variability from photoplethysmograph.

This paper proposed a method to monitor systolic blood pressure (BP) variability without using a cuff during the daytime. In this method, BP variability of long-term and short-term were separated and estimated respectively from features of phoplethysmograph (PPG) through the use of a frequency filter. Then, total variability was obtained from the combination of long-term and short-term. BP by using a cuff (ground truth) and PPG of nine healthy young subjects were measured during the daytime; then BP variability was estimated from PPG to verify the validity of our method. As a result, the correlation coefficients between measured BP variability and estimated BP variability was improved from r = 0.35 in previous method to r = 0.41 in proposed method. In particular, the estimation results in short-term BP variability showed good accuracy (r = 0.67). This method of estimating BP variability has the potential to be a simple and continuous BP monitoring system during the daytime.

Abstract 477: Chronic Baroreflex Activation Improves Baroreflex Control of Heart Rate In Obesity

Impaired baroreflex control of heart rate (BRS) and attendant risk for cardiac arrhythmias are associated with sympathetically-mediated obesity hypertension. Since both global and renal-specific sympathoinhibition have sustained antihypertensive effects in obesity, we compared BRS in obese dogs subjected to 7 days of electrical baroreflex activation (BA) and, after recovery (REC), to bilateral surgical renal denervation (RDX). After control (C) measurements and 4 weeks of high fat diet, fat intake was reduced (RF) to maintain a body weight increase of ∼ 50%, which led to an increase in mean arterial pressure (MAP) from 100±2 to 117±3 mmHg and heart rate (HR) from 86±3 to 130±4 bpm. Obesity hypertension was associated with decreased sensitivity of 24h spontaneous BRS (determined by the sequence technique from daily beat-to-beat time series) and pulse interval (PI) variability (24h SD). While both BA and RDX abolished hypertension, only BA diminished tachycardia and normalized BRS, consequently improving HR variability. Short-term systolic blood pressure variability (5 min SD) also decreased with high fat feeding and was restored to control upon reduction of fat intake (RF) during established obesity hypertension, suggesting a vasoplegic effect of fat. These data suggest that in addition to the antihypertensive effects of sympathoinhibition, BA corrects cardiac baroreflex dysfunction in obesity hypertension, presumably by enhancing cardiac vagal activity. This in turn markedly improves depressed HR variability, a known risk factor for cardiac arrhythmic events.

Relationship Between Short-Term Blood Pressure Variability and Large-Artery Stiffness in Human Hypertension

Short-term blood pressure (BP) variability predicts cardiovascular complications in hypertension, but its association with large-artery stiffness is poorly understood and confounded by methodologic issues related to the assessment of BP variations over 24 hours. Carotid-femoral pulse wave velocity (cfPWV) and 24-hour ambulatory BP were measured in 911 untreated, nondiabetic patients with uncomplicated hypertension (learning population) and in 2089 mostly treated hypertensive patients (83% treated, 25% diabetics; test population). Short-term systolic BP (SBP) variability was calculated as the following: (1) SD of 24-hour, daytime, or nighttime SBP; (2) weighted SD of 24-hour SBP; and (3) average real variability (ARV), that is, the average of the absolute differences between consecutive SBP measurements over 24 hours. In the learning population, all of the measures of SBP variability showed a direct correlation with cfPWV (SD of 24-hour, daytime, and nighttime SBP, r =0.17/0.19/0.13; weighted SD of 24-hour SBP, r =0.21; ARV, r =0.26; all P &lt;0.001). The relationship between cfPWV and ARV was stronger than that with 24-hour, daytime, or nighttime SBP (all P &lt;0.05) and similar to that with weighted SD of 24-hour SBP. In the test population, ARV and weighted SD of 24-hour SBP had stronger relationships with cfPWV than SD of 24-hour, daytime, or nighttime SBP. In both populations, SBP variability indices independently predicted cfPWV along with age, 24-hour SBP, and other factors. We conclude that short-term variability of 24-hour SBP shows an independent, although moderate, relation to aortic stiffness in hypertension. This relationship is stronger with measures of BP variability focusing on short-term changes, such as ARV and weighted 24-hour SD.

Blood pressure variability and silent cerebral damage in essential hypertension

It is recognized that blood pressure (BP) variability has prognostic significance in determining target organ damage and cardiovascular mortality and morbidity. The aim of this study was to analyze the association between blood pressure variability and the presence of silent cerebral white matter lesions in middle-aged asymptomatic essential hypertensives. We studied 43 middle-aged untreated hypertensive patients. Blood pressure variabilities (short-term and long-term) were evaluated by using both non-invasive, beat-to-beat, continuous finger 24-hour monitoring (Portapres) and oscillometric automated discontinuous ambulatory blood pressure monitoring. All patients underwent cerebral magnetic resonance imaging to detect the presence or not of white matter lesions. Hypertensive patients with cerebral white matter lesions exhibited significantly higher values of long-term systolic blood pressure variability (standard deviation of 24-hour blood pressure) measured both by continuous beat-to-beat monitoring (16.2 +/- 3.7 v 13.7 +/- 3.6 mm Hg; P = 0.047) and by ambulatory blood pressure monitoring (15.2 +/- 3.8 v 12.8 +/- 2.7 mm Hg; P = 0.022). However, these differences were not independent on blood pressure elevation and did not maintain their significance after adjusting for 24-hour systolic blood pressure. Neither short-term systolic blood pressure variability, nor short-term or long-term diastolic blood pressure variabilities showed differences between patients with and without white matter lesions. The present study indicates that long-term systolic blood pressure variability is significantly related to the presence of silent cerebral white matter lesions in essential hypertensive patients, although this relationship is partially dependent on absolute blood pressure elevation.

Short-term variability of pulse pressure and systolic and diastolic time in heart transplant recipients

In heart transplant recipients (HTR), short-term systolic blood pressure variability is preserved, whereas heart rate variability is almost abolished. Heart period is the sum of left ventricular ejection time (LVET) and diastolic time (DT). In the present time-domain prospective study, we tested the hypothesis that short-term fluctuations in aortic pulse pressure (PP) in HTR were related to fluctuations in LVET. Seventeen male HTR (age 48 +/- 6 yr) were studied 16 +/- 11 mo after transplantation. Aortic root pressure was obtained over a 15-s period using a micromanometer both at rest (n = 17) and following the cold pressor test (CPT, n = 14). There was a strong positive linear relationship between beat-to-beat LVET and beat-to-beat PP in all patients at rest and in 13 of 14 patients following CPT (each P < 0.01). The slope of this relationship showed little scatter both at rest (0.34 +/- 0.07 mmHg/ms) and following CPT (0.35 +/- 0.09 mmHg/ms, P = not significant). Given the essentially fixed heart period, DT varied inversely with LVET. As a result, in 13 of 17 HTR at rest and in 12 of 14 HTR following CPT, there was a negative linear relationship between beat-to-beat PP and DT. In conclusion, our short-term time-domain study demonstrated a strong positive linear relationship between LVET and blood pressure variability in male HTR. We also identified a subgroup of HTR in whom there was a mismatch between PP and DT.

Fractal nature of short-term systolic BP and HR variability during lower body negative pressure.

We have shown previously that the heart rate variability (HRV) signal is fractal in nature with a high degree of complexity, as given by the calculated fractal dimension (DF). We have also reported that loss of complexity, as indicated by a reduction in DF of HRV, is associated with orthostatic hypotension and impending syncope. To extend this investigation of cardiovascular responses, we have investigated the signal characteristics of short-term systolic blood pressure variability (BPV) coincident with measurements of HRV during orthostatic stress. Eight healthy men completed a test protocol of 20 min supine rest followed sequentially by 10 min at each of -5, -15, -25, -40, and -50 mmHg lower body negative pressure (LBNP) and 10 min supine recovery. We found that resting BPV and HRV were fractal with approximately 70% of both variables in the fractal component of the variability signal. The slope of the 1/f beta relationship was 1.16 +/- 0.12 for HRV and 2.31 +/- 0.17 for BPV. With increasing levels of orthostatic stress, the 1/f beta slope of HRV increased significantly to 1.68 +/- 0.08 at -50 mmHg LBNP, whereas the 1/f beta slope was unchanged for BPV. Indicators of parasympathetic and sympathetic nervous system activity derived from heart rate variability suggested reduced and increased values, respectively, as the LBNP increased. These data indicate important differences in heart rate and blood pressure control under orthostatic stress.