Blood Pressure Variability Ratio Research Articles

Prognostic Relevance of Short-Term Blood Pressure Variability. The Spanish ABPM Registry.

The prognostic relevance of short-term blood pressure (BP) variability in hypertension is not clearly established. We aimed to evaluate the association of short-term BP variability, with all-cause and cardiovascular mortality in a large cohort of patients with hypertension. We selected 59 124 patients from the Spanish Ambulatory Blood Pressure Monitoring Registry from 2004 to 2014 (median follow-up: 9.7 years). Systolic and diastolic BP SD and coefficient of variation from daytime and nighttime, weighted SD, weighted coefficient of variation, average real variability (mean of differences between consecutive readings), and BP variability ratio (ratio between systolic and diastolic 24-hour SD) were calculated through baseline 24-hour ambulatory BP monitoring. Association with all-cause and cardiovascular mortality were assessed by Cox regression models adjusted for clinical confounders and BP. Patients who died during follow-up had higher values of BP variability compared with those remaining alive. In adjusted models systolic and diastolic daytime and weighted SD and coefficient of variation, average real variability, as well as systolic nighttime SD and BP variability ratio were all significantly associated with all-cause and cardiovascular mortality. Hazard ratios for 1-SD increase in the systolic components ranged from 1.05 to 1.12 for all-cause mortality and from 1.07 to 1.17 for cardiovascular mortality. A daytime SD≥13 mm Hg, a nighttime and a weighted SD≥12 mm Hg, and an average real variability ≥10 mm Hg, all systolic, were independently associated with mortality. Short-term blood pressure variability shows a relatively weak but significant association with all-cause and cardiovascular mortality in patients with hypertension.

PULSE WAVE VELOCITY AND BLOOD PRESSURE VARIABILITY AS PROGNOSTIC INDICATORS IN VERY ELDERLY PATIENTS WITH DECOMPENSATED CHRONIC CONDITIONS

Objective: There is scarce evidence of the prognostic importance of hemodynamic measures, such as blood pressure (BP), BP variability and arterial stiffness in the very elderly population with advanced chronic conditions. We aimed to evaluate the prognostic importance of 24-hour BP, BP variability and arterial stiffness in a cohort of very elderly patients admitted to the hospital due to a decompensated chronic disease. Design and method: We studied 249 patients older than 80 (66% women), admitted due to a chronic disease decompensation (60% congestive heart failure). During admission, 24-hour brachial and central BP, BP and heart rate variabilities, aortic pulse wave velocity and BP variability ratio were determined through non-invasive 24-hour monitoring. The primary outcome was 1-year mortality. Secondary outcome was the composite of 1-year mortality or readmission. Results: Increased arterial stiffness (aortic pulse wave velocity and BP variability ratio) was associated with 1-year mortality. For each standard deviation (SD) increase in aortic pulse wave velocity and BP variability ratio, mortality increased 3.3 times and 31%, respectively, after adjustments for clinical confounders and BP. Increased BP variability (38% increase for each SD change) and reduced heart rate variability (32% increase for each SD change) also predicted 1-year mortality in fully adjusted models. No association was found between 24-hour BP (either brachial or aortic) and 1-year mortality. Conclusions: Increased aortic stiffness and BP and heart rate variabilities predict 1-year mortality in very elderly patients with decompensated chronic conditions. Measurements of such estimates could be useful in the prognostic evaluation of this specific population.

Pulse Wave Velocity and Blood Pressure Variability as Prognostic Indicators in Very Elderly Patients

There is scarce evidence for the prognostic importance of hemodynamic measures, such as blood pressure (BP), BP variability, and arterial stiffness, in the very elderly population with advanced chronic conditions. We aimed to evaluate the prognostic importance of 24 h BP, BP variability, and arterial stiffness in a cohort of very elderly patients admitted to the hospital due to a decompensated chronic disease. We studied 249 patients older than 80 (66% women; 60% congestive heart failure). Noninvasive 24 h monitoring was used to determine 24 h brachial and central BP, BP and heart rate variabilities, aortic pulse wave velocity, and BP variability ratios during admission. The primary outcome was 1-year mortality. Aortic pulse wave velocity (3.3 times for each SD increase) and BP variability ratio (31% for each SD increase) were associated with 1-year mortality, after adjustments for clinical confounders. Increased systolic BP variability (38% increase for each SD change) and reduced heart rate variability (32% increase for each SD change) also predicted 1-year mortality. In conclusion, increased aortic stiffness and BP and heart rate variabilities predict 1-year mortality in very elderly patients with decompensated chronic conditions. Measurements of such estimates could be useful in the prognostic evaluation of this specific population.

Twenty-Four-Hour Central Hemodynamic Load in Adults With and Without a History of COVID-19.

BACKGROUNDAlthough hypertension is an established risk factor for severe COVID-19 illness, little is known about the effects of COVID-19 on blood pressure (BP). Central BP measures taken over a 24-hour period using ambulatory blood pressure monitoring (ABPM) adds prognostic value in assessing cardiovascular disease (CVD) risk compared to brachial BP measures taken at a single time point. We assessed CVD risk between adults with and without a history of COVID-19 via appraisal of 24-hour brachial and central hemodynamic load from ABPM.METHODSCross-sectional analysis was performed on 32 adults who tested positive for COVID-19 (29±13 years, 22 females) and 43 adults without a history of COVID-19 (28±12 years, 26 females). Measures of 24-hour hemodynamic load included brachial and central systolic and diastolic BP, pulse pressure, augmentation index (AIx), pulse wave velocity (PWV), nocturnal BP dipping, the ambulatory arterial stiffness index (AASI), and the blood pressure variability ratio (BPVR).RESULTSParticipants who tested positive for COVID-19 experienced 6±4 COVID-19 symptoms, were studied 122±123 days after testing positive, and had mild-to-moderate COVID-19 illness. The results from independent samples t-tests showed no significant differences in any of our 24-hour, daytime, or nighttime measures of central or peripheral hemodynamic load across those with and without a history of COVID-19 (p > 0.05 for all).CONCLUSIONSNo differences in 24-hour brachial or central ABPM measures were detected between adults recovering from mild-to-moderate COVID-19 and controls without a history of COVID-19. Adults recovering from mild-to-moderate COVID-19 do not have increased 24-hour central hemodynamic load.

Instantaneous Cardiac Baroreflex Sensitivity: xBRS Method Quantifies Heart Rate Blood Pressure Variability Ratio at Rest and During Slow Breathing.

Spontaneous baroreflex sensitivity (BRS) is a widely used tool for the quantification of the cardiovascular regulation. Numerous groups use the xBRS method, which calculates the cross-correlation between the systolic beat-to-beat blood pressure and the R-R interval (resampled at 1 Hz) in a 10 s sliding window, with 0–5 s delays for the interval. The delay with the highest correlation is selected and, if significant, the quotient of the standard deviations of the R-R intervals and the systolic blood pressures is recorded as the corresponding xBRS value. In this paper we test the hypothesis that the xBRS method quantifies the causal interactions of spontaneous BRS from non-invasive measurements at rest. We use the term spontaneous BRS in the sense of the sensitivity curve is calculated from non-interventional, i.e., spontaneous, baroreceptor activity. This study includes retrospective analysis of 1828 measurements containing ECG as well as continues blood pressure under resting conditions. Our results show a high correlation between the heart rate – systolic blood pressure variability (HRV/BPV) quotient and the xBRS (r = 0.94, p < 0.001). For a deeper understanding we conducted two surrogate analyses by substituting the systolic blood pressure by its reversed time series. These showed that the xBRS method was not able to quantify causal relationships between the two signals. It was not possible to distinguish between random and baroreflex controlled sequences. It appears xBRS rather determines the HRV/BPV quotient. We conclude that the xBRS method has a potentially large bias in characterizing the capacity of the arterial baroreflex under resting conditions. During slow breathing, estimates for xBRS are significantly increased, which clearly shows that measurements at rest only involve limited baroreflex activity, but does neither challenge, nor show the full range of the arterial baroreflex regulatory capacity. We show that xBRS is exclusively dominated by the heart rate to systolic blood pressure ratio (r = 0.965, p < 0.001). Further investigations should focus on additional autonomous testing procedures such as slow breathing or orthostatic testing to provide a basis for a non-invasive evaluation of baroreflex sensitivity.

Spontaneous baroreflex sensitivity: sequence method at rest does not quantify causal interactions but rather determines the heart rate to blood pressure variability ratio

Objective:In order to quantify spontaneous baroreflex sensitivity (BRS) many groups use the sequence method (SME). In this paper we test the hypothesis that SME is quantifying causal interactions of spontaneous BRS at rest rather than, alternatively, being solely dominated by heart rate variability (HRV) and/or systolic blood pressure variability (BPV).Approach:Therefore, we retrospectively analyzed 1828 beat-to-beat time series and their corresponding systolic blood pressure during resting conditions.Main results:We found a high correlation between short-term HRV and the SME of baroreflex sensitivity of r = 0.85 (p < 0.001). The correlation is even higher between SME and the root mean square ratio of HRV and BPV (r = 0.93, p < 0.001). Surrogate analyses revealed that SME is not able to quantify causal relationships between both signals, it cannot differentiate between random and baroreflex driven sequences, and rather determines the HRV-BPV variability ratio.Significance:We conclude that SME has a potentially large methodological bias in the characterization of the capacity of the arterial baroreflex during resting conditions.

Prognostic Relevance of Short-Term Blood Pressure Variability: The Spanish ABPM Registry.

The prognostic relevance of short-term blood pressure (BP) variability in hypertension is not clearly established. We aimed to evaluate the association of short-term BP variability, assessed through ambulatory BP monitoring, with total and cardiovascular mortality in a large cohort of patients with hypertension. We selected 63 910 subjects from the Spanish ABPM Registry from 2004 to 2014, with a median follow-up of 4.7 years. Systolic and diastolic BP SD from 24 hours, daytime, and nighttime, weighted SD (mean of daytime and nighttime SD weighted for period duration), average real variability (mean of differences between consecutive readings), variation independent of the mean, and BP variability ratio (ratio between systolic and diastolic 24-hour SD) were calculated through 24-hour ambulatory BP monitoring performed at baseline. Association with total and cardiovascular mortality (obtained through death certificates) were assessed by Cox regression models adjusted for clinical confounders and BP. Patients who died during follow-up had higher values of BP variability compared with those remaining alive. In fully adjusted models, daytime, nighttime, and weighted SD, systolic and diastolic, as well as diastolic average real variability, were all significantly associated with total and cardiovascular mortality. Hazard ratios for 1 SD increase ranged from 1.05 to 1.09 for total mortality and from 1.07 to 1.12 for cardiovascular mortality. A nighttime systolic SD ≥12 mm Hg was independently associated with total (hazard ratio: 1.13 [95% CI, 1.06-1.21]) and cardiovascular mortality (hazard ratio: 1.21 [95% CI, 1.09-1.36]). We conclude that short-term BP variability is independently associated with total and cardiovascular mortality in patients with hypertension.

Association of Blood Pressure Variability Ratio With Glomerular Filtration Rate Independent of Blood Pressure and Pulse Wave Velocity.

Blood pressure variability ratio (BPVR)(derived from within-subject SD of 24-hour ambulatory blood pressure [BP]) predicts all-cause mortality independent of BP and has a similar prognostic ability to ambulatory arterial stiffness (AASI). Whether BPVR, and AASI, offer prognostic information beyond measurements of arterial stiffness at a given pressure, as indexed by pulse wave velocity (PWV), is not known. We assessed whether BPVR and AASI were associated with indices of subclinical organ damage (TOD) [estimated glomerular filtration rate (eGFR), left ventricular mass index, early-to-late transmitral velocity (E/A), carotid intima-media thickness (IMT)] independent of BP, and whether BPVR-TOD and AASI-TOD relations were independent of PWV (applanation tonometry) in 772 randomly selected participants from an urban, developing community. AASI was derived from 24-hour diastolic BP vs. systolic BP standard linear regression. On bivariate analyses, BPVR, AASI, and PWV were correlated with all indices of TOD (P < 0.0005). However, after adjustments for potential confounders including age and 24-hour mean BP, BPVR, and PWV (P < 0.005 to P < 0.0001), but not AASI (P > 0.25), were independently associated with eGFR, but not other indices of TOD. Importantly, the BPVR-eGFR relation was independent of BP variability (P < 0.005) and PWV (P < 0.001). BPVR was negatively associated with eGFR independent of mean BP, BP variability, and PWV. Therefore, in the prediction of cardiovascular risk, measurements of arterial stiffening (BPVR) may provide information beyond the impact of arterial stiffness.

Correlation between visit-to-visit and short-term blood pressure variability calculated using different methods and glomerular filtration rate.

The aim of this study was to explore the correlation between visit-to-visit and short-term blood pressure variability (BPV), including systolic BPV (SBPV) and diastolic BPV (DBPV), calculated using different methods, and the glomerular filtration rate (GFR) in a late, middle-aged population. Using cluster sampling, we randomly selected retired employees of the Kailuan Group who were ⩾60 years and participated in a third health examination for 24-h ambulatory blood pressure monitoring and inspection. Among the 3064 randomly selected observation subjects, 2464 were included based on the criteria. BPV was calculated using s.d., coefficient of variation (CV, s.d./Mean), variability independent of mean (VIM, s.d./Meanx) and BPV ratio (BPVR, s.d. (SBPV)/s.d. (DBPV)). Multivariate linear regression was used to analyse the correlation between estimated GFR (eGFR) and BPV calculated using different methods. The mean age of 2464 subjects was 67.4±6.1 years, with 1667 male subjects (67.7%). A total of 2104 cases were included in the visit-to-visit BPV group, and 1382 in the short-term BPV group. SBPV calculated using different methods showed statistically significant increasing trends for the SBP versus all s.d. and short-term BPVR. There was a significant, positive correlation between the visit-to-visit and short-term BPV calculated using different methods, which were all negatively correlated with eGFR (P<0.05). Multivariate linear regression analysis showed that, with correction for possible confounding factors, SBPV (24-h s.d., CV and VIM, and daytime CV and night time CV) and all DBPV demonstrated negative linear relationships with eGFR (P<0.05).

Vascular and Cardiac Target Organ Damage in Type 2 Diabetics With and Without Diabetic Retinopathy

Objective: In this study, we sought to assess the differences in cardiac and vascular end-organ damage in type 2 diabetics, with and without diabetic retinopathy. Methods: A cross-sectional study of 131 diabetic patients (44 with diabetic retinopathy and 87 without diabetic retinopathy). Retinography was performed with a Topcon TRC NW 200 non-mydriatic retinal camera. Using the Early Treatment of Diabetic Retinopathy Study Severity Scale, two independent observers graded the retinopathy. Pulse-wave velocity, ambulatory arterial stiffness indices, ambulatory arterial stiffness indices to blood pressure variability ratio, carotid intima–media thickness, and ankle/brachial index were used as markers of vascular damage. Left ventricular hypertrophy was evaluated by the Cornell voltage–duration product and Lewis Index. Results: A total of 33.60% of the subjects had diabetic retinopathy. The patients with diabetic retinopathy were more likely to be women (p=0.031), be insulin users (p=0.001), have a longer duration of disease (p=0.033), and have poorer blood glucose control (HbA1c 6.98 in patients with diabetic retinopathy versus 6.40 in patients without diabetic retinopathy) (p=0.012). Patients with diabetic retinopathy did not statistically differ from diabetics without retinopathy with regards to cardiac or vascular target organ damage. However, patients with diabetic retinopathy showed a trend (defined as a p-value ranging from 0.051 to 0.15) toward a higher resting heart rate, higher ratio of night/day SBP, higher ratio of night/day DBP, higher resting ambulatory systolic blood pressure measure (mmHg), higher resting ambulatory diastolic blood pressure measure (mmHg), higher ASSI-BPVR, and higher Lewis Index. Conclusions: Although the sample size limited the conclusions that could be drawn between diabetic retinopathy and levels of vascular and cardiac target organ damage, trends were observed in a number of indices for these conditions and measures thereof.

Ambulatory arterial stiffness indices and target organ damage in hypertension

BackgroundThe present study was designed to evaluate which arterial stiffness parameter - AASI or the home arterial stiffness index (HASI) - correlates best with vascular, cardiac and renal damage in hypertensive individuals.MethodsA cross-sectional study was carried out involving 258 hypertensive patients. AASI and HASI were defined as the 1-regression slope of diastolic over systolic blood pressure readings obtained from 24-hour recordings and home blood pressure over 6 days. Renal damage was evaluated by glomerular filtration rate (GFR) and microalbuminuria; vascular damage by carotid intima-media thickness (IMT), pulse wave velocity (PWV) and ankle/brachial index (ABI); and left ventricular hypertrophy by the Cornell voltage-duration product (VDP) and the Novacode index.ResultsAASI and HASI were not correlated with microalbuminuria, however AASI and HASI- blood pressure variability ratio (BPVR) showed negative correlation with GRF. The Cornell PDV was positively correlated with AASI- BPVR-Sleep (r = 0.15, p < 0.05) and the left ventricular mass index with HASI-BPVR (r = 0.19, p < 0.01). Carotid IMT and PWV were positively correlated with all the parameters except the HASI, while ABI was negatively correlated with AASI and Awake-AASI. After adjusting for age, gender and 24 hours heart rate, statistical significance remains of the IMT with AASI, Awake AASI and AASI-BPVR. PWV with the AASI, Awake-AASI and Sleep-AASI. ABI with AASI and Awake-AASI. Odd Ratio to presence target organ damage was for AASI: 10.47(IC95% 1.29 to 65.34), Awake-AASI: 8.85(IC95% 1.10 to 71.04), Sleep-AASI: 2.19(IC95% 1.10 to 4.38) and AASI-BPVR-night: 4.09 (IC95% 1.12 to 14.92).ConclusionsAfter adjusting for age, gender and 24-hour heart, the variables that best associated with the variability of IMT, PWV and ABI were AASI and Awake-AASI, and with GFR was HASI-BPVR.

Peripheral Augmentation Index is Associated With the Ambulatory Arterial Stiffness Index in Patients With Hypertension

Background: Vascular dysfunction is highly prevalent if not ubiquitous in patients with hypertension. We compared two different measures of vascular function obtained from digital volume waveforms with measures of ventricular-vascular load derived from 24-hour blood pressure (BP) recordings in patients with hypertension. Methods: Digital pulsatile volume waveforms were captured via plethysmography (peripheral arterial tone, PAT) and used to derive augmentation index (a measure of ventricular-vascular coupling) and the pulse wave amplitude-reactive hyperemia index (a measure of microvascular reactivity). Ambulatory arterial stiffness index (AASI) and the BP variability ratio (BPVR) were derived from 24-hour ambulatory BP recordings. Results: There was a positive association between PAT-AIx and AASI (r = 0.52, P 0.05). PWA-RHI was not associated with AASI or BPVR (P > 0.05). Conclusions: PAT-AIx is associated with ambulatory measures of vascular function and may offer clinical insight into vascular burden and cardiovascular disease risk in patients with hypertension independent of information obtained from PWA-RHI. Cardiol Res. 2011;2(5):218-223 doi: https://doi.org/10.4021/cr92w

Can Salt Sensitivity of Blood Pressure Be Assessed Without Changing Salt Diet?

See related article, pp 180–185 Blood pressure is responsive to sodium intake in many patients with essential hypertension. It seems that subjects of African-American ancestry and older subjects are most sensitive to salt.1 Yet, there is no agreement on how such salt sensitivity is determined: frequently, such measurements involve 2 different periods on high- and low-sodium diets; others involve intravenous sodium loading and then low-salt diet and furosemide depletion. In different studies, the definition of salt sensitivity and related procedures differ substantially and quite arbitrarily (or perhaps empirically).1,–,3 Regardless of definition, in research settings salt loading or depletion is short term, while in reality, it is the long-term exposure that counts, especially with the recent recognition that sodium can accumulate in the skin and perhaps other tissues.4 Hypertensive subjects with salt sensitivity retain salt. However, salt retention also exists in other conditions. In renal failure, it is likely to be associated with hypertension, while not necessarily so in heart failure or cirrhosis of the liver. Healthy subjects with normal blood pressure may also be salt sensitive and are then more likely to become hypertensive over time.1 In individuals with salt-sensitive hypertension, high sodium intake expands vascular volume, and arterial pressure rises along with cardiac output. Urinary sodium excretion increases in parallel to blood pressure elevation, but balance is maintained at increased vascular pressures compared …

Peripheral Augmentation Index is Associated With the Ambulatory Arterial Stiffness Index in Patients With Hypertension.

BackgroundVascular dysfunction is highly prevalent if not ubiquitous in patients with hypertension. We compared two different measures of vascular function obtained from digital volume waveforms with measures of ventricular-vascular load derived from 24-hour blood pressure (BP) recordings in patients with hypertension.MethodsDigital pulsatile volume waveforms were captured via plethysmography (peripheral arterial tone, PAT) and used to derive augmentation index (a measure of ventricular-vascular coupling) and the pulse wave amplitude-reactive hyperemia index (a measure of microvascular reactivity). Ambulatory arterial stiffness index (AASI) and the BP variability ratio (BPVR) were derived from 24-hour ambulatory BP recordings.ResultsThere was a positive association between PAT-AIx and AASI (r = 0.52, P < 0.05). There was also a positive association between PAT-AIx and BPVR (r = 0.37, P < 0.05). PAT-AIx was not associated with PWA-RHI (r = -0.14, P > 0.05). PWA-RHI was not associated with AASI or BPVR (P > 0.05).ConclusionsPAT-AIx is associated with ambulatory measures of vascular function and may offer clinical insight into vascular burden and cardiovascular disease risk in patients with hypertension independent of information obtained from PWA-RHI.

The association of a simple blood pressure-independent parameter derived from ambulatory blood pressure variability with short-term mortality

We explored the predictive ability of the blood pressure variability ratio (BPVR), defined as the ratio of 24-h ambulatory systolic blood pressure variability to diastolic variability, and evaluated its predictable relation with blood pressure and the Ambulatory Arterial Stiffness Index (AASI). A total of 3433 consecutive patients were followed up to 16 years for all-cause mortality. Blood pressure variability was expressed by the standard deviation. BPVR, which is the systolic-on-diastolic slope estimated by a known type of symmetric regression ('reduced major axis'), was compared with other expressions of this slope and with AASI using other regression procedures. Time-dependent Cox proportional hazard models, adjusted for demographics, 24-h mean blood pressure, 24-h pulse pressure and dipping were used to assess the association of BPVR and slope-related parameters with all-cause mortality. We found that Pearson's correlation between BPVR and the symmetric slope was 0.957, and between 1-1/BPVR (an AASI-equivalent expression) and the symmetric version of AASI was 0.973. BPVR was entirely independent of mean arterial pressure (r=0.013). Systolic and diastolic ambulatory blood pressure variability was not significantly associated with mortality. Over 16 years, BPVR predicted all-cause mortality [hazard ratio=1.21 (95% CI 1.05-1.40) per 1 s.d. increase]. In time-dependent models, increased BPVR was strongly associated with an 18-month mortality, weakly related to 7 years mortality, showing no effect thereafter. Thus, the ratio between 24-h systolic and diastolic blood pressure variability, readily available from ambulatory monitoring reports, is an easy-to-calculate systolic-on-diastolic slope. It is a blood pressure-independent measure believed to express an arterial property, with prognostic power similar to that of AASI.

Ambulatory Blood Pressure Measurement

One of the consequences of hypertension is increasing stiffness of the arteries, which leads to cardiovascular events and increased mortality.1 Clearly this process is a continuous one and, contrary to acceptance that such change is inevitable, it is not now unreasonable to assume that if stiffening in the arterial system could be detected at an early rather than at a late stage, therapeutic interventions might be initiated to delay or even prevent its occurrence. However, measuring arterial stiffness requires special equipment and trained staff, facilities that are not generally available and that are, moreover, costly. It has been proposed recently that a measure of arterial stiffness could be obtained from the routine use of ambulatory blood pressure measurement (ABPM) by using the dynamic relationship between diastolic and systolic blood pressure over 24 hours, calculated as 1 minus the regression slope of diastolic on systolic blood pressure. The rationale underlying the ambulatory arterial stiffness index (AASI) is that average distending pressure varies during the day and that the relation between diastolic and systolic blood pressure, with this changing distending pressure, depends largely on the structural and functional characteristics of the large arteries. In the Dublin Outcome Study, AASI predicted cardiovascular mortality in a large cohort of hypertensive individuals. Moreover, this prediction withstood additional adjustment for other risk factors, including pulse pressure. Interestingly, AASI was a stronger predictor of fatal …