Cardiovascular End Points and Mortality Are Not Closer Associated With Central Than Peripheral Pulsatile Blood Pressure Components

Accuracy of methods to estimate central aortic SBP via upper arm cuff: a systematic review and meta-analysis

OBJECTIVES

Central aortic BP may predict cardiovascular outcomes better than upper arm brachial BP. In recent years, technology has enabled central BP estimation by recording a peripheral BP waveform from a standard upper arm cuff. The accuracy of these devices is not well documented, and this study aimed to address this issue.

METHODS

This study was a systematic review, conducted according to PRISMA guidelines, of observational studies published between 2008 and 2023 that reported accuracy testing of cuff-based central BP devices, compared with reference invasive aortic BP. The primary analysis was stratified according to each commercially available device. Pooled estimates were calculated using random-effects models based on mean differences and standard errors.

RESULTS

Six thousand four hundred and fifteen studies were screened, and 27 studies met inclusion criteria (plus one unpublished study). This generated data for seven devices that are commercially available, which were tested among 2125 adult participants. There was very high heterogeneity when all devices were pooled ( I2  = 97.5%), and, when stratified by device, the accuracy of estimated central BP was highly device-dependent (range of accuracy across different devices -12.4 mmHg (-16.3 to -8.5) to 3.2 mmHg (0.2-6.1). Two of the seven commercially available devices had not undergone external validation testing.

CONCLUSION

The accuracy of commercially available cuff-based central BP devices is highly device-specific and not all are accurate for the estimation of central SBP. These findings have major implications for the appropriate interpretation of studies that use cuff-based estimated central BP.

Association of cardiovascular events with central systolic blood pressure: A systemic review and meta-analysis

Central blood pressure confers cardiovascular risk prediction ability, but whether the association between central systolic blood pressure (cSBP) and cardiovascular endpoints is independent of peripheral systolic blood pressure (pSBP) remains controversial. This systematic review and meta-analysis aim to investigate the associations between cSBP and cardiovascular endpoints in models including and excluding pSBP, respectively. Observational studies assessing the risk of composite cardiovascular endpoints with baseline cSBP were searched in PubMed, Embase, Scopus, Web of Science, and Cochrane Library to May 31, 2022. Risk of bias was assessed by the Newcastle-Ottawa Quality Assessment Scale, and random-effects models were used to pool estimates. Finally, 48 200 participants from 19 studies with a mean age of 59.0 ± 6.9 years were included. Per 10 mmHg increase of cSBP was associated with higher risk of composite cardiovascular outcomes (risk ratio [RR]: 1.14 [95%CI 1.08-1.19]) and cardiovascular death (RR: 1.18 [95%CI 1.08-1.30]), and the associations still existed after adjusting for pSBP (RR: 1.13 [95%CI 1.05-1.21] for composite cardiovascular endpoints; RR: 1.25 [95%CI 1.09-1.43] for cardiovascular death). In pSBP-unadjusted studies, increased cSBP was also associated with higher risk of all-cause mortality and stroke, but not in the pSBP-adjusted studies. Both cSBP and pSBP were similarly significantly associated with composite cardiovascular endpoints in models containing them separately and simultaneously. cSBP was significantly associated with cardiovascular events, independently of pSBP. Central or peripheral SBP could supplement cardiovascular risk assessment besides each other.

Age-dependent association of central blood pressure with cardiovascular outcomes: a cohort study involving 34 289 participants using the UK biobank

BACKGROUND

It remained unclear whether central blood pressures (BP) was more closely associated with cardiovascular disease (CVD) than brachial BP in different age groups.

OBJECTIVES

To investigate the age-stratified association of CVD with brachial and central BPs, and to evaluate corresponding improvement in model performance.

METHODS

This cohort study included 34 289 adults without baseline CVD from the UK Biobank dataset. Participants were categorized into middle-aged and older aged groups using the cut-off of age 65 years. The primary endpoint was a composite cardiovascular outcome consisting of cardiovascular mortality combined with nonfatal coronary events, heart failure and stroke. Multivariable-adjusted hazard ratios expressed CVD risks associated with BP increments of 10 mmHg. Akaike Information Criteria (AIC) was used for model comparisons.

RESULTS

In both groups, CVD events were associated with brachial or central SBP ( P  ≤ 0.002). Model fit was better for central SBP in middle-aged adults (AIC 4427.2 vs. 4429.5), but model fit was better for brachial SBP in older adults (AIC 10 246.7 vs. 10 247.1). Central SBP remained significantly associated to CVD events [hazard ratio = 1.05; 95% confidence interval (CI) 1.0-1.1] and improved model fit (AIC = 4426.6) after adjustment of brachial SBP only in the middle-aged adults. These results were consistent for pulse pressure (PP).

CONCLUSION

In middle-aged adults, higher central BPs were associated with greater risks of CVD events, even after adjusting for brachial BP indexes. For older adults, the superiority of central BP was not observed. Additional trials with adequate follow-up time will confirm the role of central BP in estimating CVD risk for middle-aged individuals.

Vascular phenotypes in early hypertension

The study characterises vascular phenotypes of hypertensive patients utilising machine learning approaches. Newly diagnosed and treatment-naïve primary hypertensive patients without co-morbidities (aged 18-55, n = 73), and matched normotensive controls (n = 79) were recruited (NCT04015635). Blood pressure (BP) and BP variability were determined using 24 h ambulatory monitoring. Vascular phenotyping included SphygmoCor® measurement of pulse wave velocity (PWV), pulse wave analysis-derived augmentation index (PWA-AIx), and central BP; EndoPAT™-2000® provided reactive hyperaemia index (LnRHI) and augmentation index adjusted to heart rate of 75bpm. Ultrasound was used to analyse flow mediated dilatation and carotid intima-media thickness (CIMT). In addition to standard statistical methods to compare normotensive and hypertensive groups, machine learning techniques including biclustering explored hypertensive phenotypic subgroups. We report that arterial stiffness (PWV, PWA-AIx, EndoPAT-2000-derived AI@75) and central pressures were greater in incident hypertension than normotension. Endothelial function, percent nocturnal dip, and CIMT did not differ between groups. The vascular phenotype of white-coat hypertension imitated sustained hypertension with elevated arterial stiffness and central pressure; masked hypertension demonstrating values similar to normotension. Machine learning revealed three distinct hypertension clusters, representing 'arterially stiffened', 'vaso-protected', and 'non-dipper' patients. Key clustering features were nocturnal- and central-BP, percent dipping, and arterial stiffness measures. We conclude that untreated patients with primary hypertension demonstrate early arterial stiffening rather than endothelial dysfunction or CIMT alterations. Phenotypic heterogeneity in nocturnal and central BP, percent dipping, and arterial stiffness observed early in the course of disease may have implications for risk stratification.

Non-Invasive Estimation of Central Systolic Blood Pressure by Radial Tonometry: A Simplified Approach

BACKROUND

Central systolic blood pressure (cSBP) provides valuable clinical and physiological information. A recent invasive study showed that cSBP can be reliably estimated from mean (MBP) and diastolic (DBP) blood pressure. In this non-invasive study, we compared cSBP calculated using a Direct Central Blood Pressure estimation (DCBP = MBP2/DBP) with cSBP estimated by radial tonometry.

METHODS

Consecutive patients referred for cardiovascular assessment and prevention were prospectively included. Using applanation tonometry with SphygmoCor device, cSBP was estimated using an inbuilt generalized transfer function derived from radial pressure waveform, which was calibrated to oscillometric brachial SBP and DBP. The time-averaged MBP was calculated from the radial pulse waveform. The minimum acceptable error (DCBP-cSBP) was set at ≤5 (mean) and ≤8 mmHg (SD).

RESULTS

We included 160 patients (58 years, 54%men). The cSBP was 123.1 ± 18.3 mmHg (range 86-181 mmHg). The (DCBP-cSBP) error was -1.4 ± 4.9 mmHg. There was a linear relationship between cSBP and DCBP (R2 = 0.93). Forty-seven patients (29%) had cSBP values ≥ 130 mmHg, and a DCBP value > 126 mmHg exhibited a sensitivity of 91.5% and specificity of 94.7% in discriminating this threshold (Youden index = 0.86; AUC = 0.965).

CONCLUSIONS

Using the DCBP formula, radial tonometry allows for the robust estimation of cSBP without the need for a generalized transfer function. This finding may have implications for risk stratification.

Hypertension in China: epidemiology and treatment initiatives

The past two to three decades have seen a steady increase in the prevalence of hypertension in China, largely owing to increased life expectancy and lifestyle changes (particularly among individuals aged 35-44 years). Data from the China hypertension survey conducted in 2012-2015 revealed a high prevalence of grade 3 hypertension (systolic blood pressure ≥180 mmHg and diastolic blood pressure ≥110 mmHg) in the general population, which increased with age to up to 5% among individuals aged ≥65 years. The risk profile of patients with hypertension in China has also been a subject of intense study in the past 30 years. Dietary sodium and potassium intake have remained largely the same in China in the past three decades, and salt substitution strategies seem to be effective in reducing blood pressure levels and the risk of cardiovascular events and death. However, the number of individuals with risk factors for hypertension and cardiovascular disease in general, such as physical inactivity and obesity, has increased dramatically in the same period. Moreover, even in patients diagnosed with hypertension, their disease is often poorly managed owing to a lack of patient education and poor treatment compliance. In this Review, we summarize the latest epidemiological data on hypertension in China, discuss the risk factors for hypertension that are specific to this population, and describe several ongoing nationwide hypertension control initiatives that target these risk factors, especially in the low-resource rural setting.

Brachial and central hypertension in relation to coronary stenosis in patients with coronary angiography

The clinical significance of central beyond brachial blood pressure (BP) remains unclear. In patients who underwent coronary angiography, the authors explored whether elevated central BP would be associated with coronary arterial disease (CAD) irrespective of the status of brachial hypertension. From March 2021 to April 2022, 335 patients (mean age 64.9 years, 69.9% men) hospitalized for suspected CAD or unstable angina were screened in an ongoing trial. CAD was defined if a coronary stenosis of ≥50%. According to the presence of brachial (non-invasive cuff systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg) and central (invasive systolic BP ≥130 mmHg) hypertension, patients were cross-classified as isolated brachial hypertension (n = 23), isolated central hypertension (n = 93), and concordant normotension (n = 100) or hypertension (n = 119). In continuous analyses, both brachial and central systolic BPs were significantly related to CAD with similar standardized odds ratios (OR, 1.47 and 1.45, p < .05). While categorical analyses showed that patients with isolated central hypertension or concordant hypertension had a significantly higher prevalence of CAD and the Gensini score than those with concordant normotension. Multivariate-adjusted OR (95% confidence interval [CI]) for CAD was 2.24 (1.16 to 4.33, p = .009) for isolated central hypertension and 3.02 (1.58 to 5.78, p < .001) for concordant hypertension relative to concordant normotension. The corresponding OR (95% CI) of a high Gensini score was 2.40 (1.26-4.58) and 2.17 (1.19-3.96), respectively. In conclusion, regardless of the presence of brachial hypertension, elevated central BP was associated with the presence and severity of CAD, indicating that central hypertension is an important risk factor for coronary atherosclerosis.

The acute adaptation of skin microcirculatory perfusion in vivo does not involve a local response but rather a centrally mediated adaptive reflex

Introduction: Cardiovascular homeostasis involves the interaction of multiple players to ensure a permanent adaptation to each organ's needs. Our previous research suggested that changes in skin microcirculation-even if slight and distal-always evoke an immediate global rather than "local" response affecting hemodynamic homeostasis. These observations question our understanding of known reflexes used to explore vascular physiology, such as reactive hyperemia and the venoarteriolar reflex (VAR). Thus, our study was designed to further explore these responses in older healthy adults of both sexes and to potentially provide objective evidence of a centrally mediated mechanism governing each of these adaptive processes. Methods: Participants (n = 22, 52.5 ± 6.2 years old) of both sexes were previously selected. Perfusion was recorded in both feet by laser Doppler flowmetry (LDF) and photoplethysmography (PPG). Two different maneuvers with opposite impacts on perfusion were applied as challengers to single limb reactive hyperemia evoked by massage and a single leg pending to generate a VAR. Measurements were taken at baseline (Phase I), during challenge (Phase II), and recovery (Phase III). A 95% confidence level was adopted. As proof of concept, six additional young healthy women were selected to provide video imaging by using optoacoustic tomography (OAT) of suprasystolic post-occlusive reactive hyperemia (PORH) in the upper limb. Results: Modified perfusion was detected by LDF and PPG in both limbs with both hyperemia and VAR, with clear systemic hemodynamic changes in all participants. Comparison with data obtained under the same conditions in a younger cohort, previously published by our group, revealed that results were not statistically different between the groups. Discussion: The OAT documentary and analysis showed that the suprasystolic pressure in the arm changed vasomotion in the forearm, displacing blood from the superficial to the deeper plexus vessels. Deflation allowed the blood to return and to be distributed in both plexuses. These responses were present in all individuals independent of their age. They appeared to be determined by the need to re-establish hemodynamics acutely modified by the challenger, which means that they were centrally mediated. Therefore, a new mechanistic interpretation of these exploratory maneuvers is required to better characterize in vivo cardiovascular physiology in humans.

Relative prognostic importance of aortic and brachial blood pressures for cardiovascular and mortality outcomes in patients with resistant hypertension and diabetes: a two cohorts prospective study

OBJECTIVE

The prognostic importance of derived central/aortic blood pressures (BPs) in relation to brachial office and ambulatory BPs has never been investigated in patients with resistant hypertension (RHT) or type 2 diabetes (T2D). We aimed to evaluate it in two cohorts with 532 individuals with RHT and 467 with T2D (median follow-ups 4.4 and 7.3 years, respectively).

METHODS

Central/aortic pressure waveforms were estimated by radial tonometry by a type 1 device (SphygmoCor device/software), and other parameters of central hemodynamics (augmentation index and Buckberg indices) were calculated. Multivariate Cox regressions examined the associations between central and peripheral BPs with cardiovascular events incidence and mortality, and C -statistics and the integrated discrimination improvement index evaluated the improvement in risk discrimination.

RESULTS

During follow-up, there were 52 cardiovascular events and 51 all-cause deaths in the RHT and 104 and 137 in the T2D cohort. No aortic BP was better than its brachial counterpart in predicting risk or improving discrimination for any outcome in either cohort. In the RHT cohort, ambulatory BPs were superior to central and office-brachial BPs. Otherwise, the augmentation index in RHT (hazard ratios: 1.5, for 1-SD increment) and the Buckberg index in T2D (hazard ratios: 0.7-0.8) were independent predictors of cardiovascular/mortality outcomes, and improved risk discrimination (integrated discrimination improvement up to 25% in RHT and 15% in T2D).

CONCLUSION

Derived aortic BPs by a type 1 device did not improve cardiovascular/mortality risk prediction over brachial BPs in our cohorts of patients with RHT and T2D, but additional parameters of central hemodynamics may be useful.

What did we learn from the International Databases on Ambulatory and Home Blood Pressure in Relation to Cardiovascular Outcome?

To assess in individual-person meta-analyses how out-of-office blood pressure (BP) contributes to risk stratification and the management of hypertension, an international consortium set up the International Databases on Ambulatory (IDACO) and Home (IDHOCO) Blood Pressure in Relation to Cardiovascular Outcome. This review summarizes key findings of recent IDACO/IDHOCO articles. Among various BP indexes derived from office and ambulatory BP recordings, the 24-h and nighttime BP level were the best predictors of adverse health outcomes. Second, using the 10-year cardiovascular risk associated with guideline-endorsed office BP thresholds as reference, corresponding thresholds were derived for home and ambulatory BP. Stratified by the underlying cardiovascular risk, the rate of cardiovascular events in white-coat hypertensive patients and matched normotensive controls were not substantially different. The observation that masked hypertension carries a high cardiovascular risk was replicated in Nigerian Blacks, using home BP monitoring. The thresholds for 24-h mean arterial pressure, i.e., the BP component measured by oscillometric devices, delineating normotension, elevated BP and hypertension were <90, 90 to 92 and ≥92 mmHg. At young age, the absolute risk associated with out-of-office BP was low, but the relative risk was high, whereas with advancing age, the relative risk decreased and the absolute risk increased. Using pulse pressure as an exemplary case, the relative risks of death, cardiovascular endpoints and stroke decreased over 3-fold from 55 to 75 years of age, whereas in contrast absolute risk rose 3-fold. In conclusion, IDACO/IDHOCO forcefully support the notion that the pressing need to curb the hypertension pandemic cannot be met without out-of-the-office BP monitoring.

Association Between Arterial Stiffness and New-Onset Heart Failure: The Kailuan Study

BACKGROUND

Arterial stiffness (AS) was associated with heart failure (HF) in previous studies based on specific populations with small samples and the effects of age and blood pressure on AS were not taken into account. Whether AS was independently associated with new-onset HF in community dwellers has not been fully investigated to date.

METHODS

Individuals who participated in health evaluations and underwent synchronized brachial-ankle pulse wave velocity (baPWV) screening in 2010 to 2019 were included. They were free of HF and atrial fibrillation at baseline. The participants were allocated to 3 groups according to their baPWV values. Normal AS was defined as baPWV <1400 cm/s, borderline AS was defined as 1400≤baPWV<1800 cm/s, and elevated AS was defined as baPWV ≥1800 cm/s. Cox proportional hazard regression was used to calculate hazard ratios with 95% CIs of new-onset HF across different AS groups.

RESULTS

A total of 40 064 participants were enrolled with a mean age of 48.81±12.67 years. During a mean 5.53 years of follow-up, 411 participants developed HF. Compared with the normal AS group, the hazard ratio (95% CI) for incident HF was 1.97 (1.36-2.86) for the borderline AS group and 2.24 (1.49-3.38) for the elevated AS group in the multivariable-adjusted model. For each 1 SD (359 cm/s) increase in baPWV, the hazard ratio (95% CI) for new-onset HF was 1.10 (1.02-1.20).

CONCLUSIONS

AS was positively associated with a higher risk of new-onset HF independently of traditional risk factors, with a dose-responsive effect.

Central blood pressure estimation in type 1 diabetes: impact and implications of peripheral calibration method

OBJECTIVE

Peripheral blood pressure (BP) waveforms are used for noninvasive central BP estimation. Central BP could assist in cardiovascular risk assessment in patients with type 1 diabetes mellitus (T1DM). However, correct calibration of peripheral BP waveforms is important to accurately estimate central BP. We examined differences in central BP estimated by radial artery tonometry depending on which brachial BP (SBP/DBP vs. MAP/DBP) is used for calibration of the radial waveforms, for the first time in T1DM.

METHODS

A cross-sectional study in T1DM patients without known cardiovascular disease. Radial artery BP waveforms were acquired using applanation tonometry ( SphygmoCor ) for the estimation of central SBP, central pulse pressure (PP) and central augmentation pressure, using either brachial SBP/DBP or MAP/DBP for the calibration of the radial pressure waveforms.

RESULTS

Fifty-four patients (age: 46 ± 9.5 years; T1DM duration: 27 ± 8.8 years) were evaluated. Central BP parameters were significantly higher when brachial MAP/DBP-calibration was used compared with brachial SBP/DBP-calibration (7.5 ± 5.04, 7.5 ± 5.04 and 1.5 ± 1.36 mmHg higher central SBP, central PP and central augmentation pressure, respectively, P  < 0.001).

CONCLUSION

In patients with T1DM, there are significant differences in central BP values estimated with radial artery tonometry, depending on the method used for calibration of the radial waveforms. Brachial MAP/DBP-calibration resulted in consistently higher central BP as compared to using brachial SBP/DBP, leading to patient re-stratification. Hence, the accuracy of noninvasive estimation of central BP by radial tonometry is dependent on calibration approach, and this problem must be resolved in validation studies using an invasive reference standard to determine which method best estimates true central BP.

The Relationship of Vascular Aging to Reduced Cognitive Function: Pulsatile and Steady State Arterial Hemodynamics

Aortic stiffness increases with age and is a robust predictor of cerebrovascular events and cognitive decline including Alzheimer's disease and other forms of dementia. Recent clinical studies have investigated the association between proximal aortic stiffness and pulsatile energy transmission that has deleterious effects on the cerebrovascular network in order to identify potential therapeutic targets. Aging causes disproportionate stiffening of the aorta compared with the carotid arteries, reducing protective impedance mismatches at their interface, increasing the transmission of destructive pulsatile pressure and energy to the cerebral circulation, and leading to cerebral small vessel disease. Thus, aortic stiffening and high-flow pulsatility are associated with alterations in the microvasculature of the brain, vascular endothelial dysfunction, and white matter damage, which contribute to impaired memory function with advancing age. Previous studies have also shown that silent lacunar infarcts and white matter hyperintensities are strongly associated with arterial stiffness. More and more evidence suggests that vascular etiologies, including aortic stiffness, impedance match, and microvascular damage, are associated with cognitive impairment and the pathogenesis of dementia. The measurement of arterial flow and pressure can help understand pulsatile hemodynamics and its impact on vital organs. Interventions that reduce aortic stiffness, such as improvement of the living environment, management of risk factors, and innovation and development of novel drugs, may reduce the risk for dementia.

Viewpoint: The Case for Non-Invasive Central Aortic Pressure Monitoring in the Management of Hypertension

Elevated central aortic pressure indices (e.g., systolic pressure and pulse pressure) predict cardiovascular (CV) events and mortality in addition to structural changes (e.g., left ventricular hypertrophy, carotid intima-media thickness and reduced glomerular filtration rate). These elevated risks have been shown in multiple studies to be superior to, and in others, at least as high as that associated with brachial pressures. Threshold values for the diagnosis of elevated central arterial pressures have been defined and can be considered target goals of treatment. Measurements of central arterial pressures can be incorporated into the current approaches to hypertension management utilizing currently available non-invasive devices that measure central pressures during the measurement of brachial BP. The objective of this review is to outline the rationale and evidence supporting incorporation of central aortic pressure monitoring into the care of patients with hypertension.

Pre-Frailty Phenotype and Arterial Stiffness in Older Adults Free of Cardiovascular Diseases

PURPOSE

Arterial stiffness is a subclinical marker of cardiovascular disease (CVD). The pre-frailty phenotype is associated with a higher risk for CVD. This study investigated the association between the pre-frailty phenotype and arterial stiffness in community-dwelling older adults without diagnosed CVD.

METHODS

In total, 249 community-dwelling older adults aged 60-80 years were included in this cross-sectional study. The pre-frailty phenotype was defined by the standardized Fried criteria (muscle weakness; slow walking speed; low physical activity; unintentional weight loss; self-reported exhaustion). Participants with one or two standardized Fried criteria were classified as pre-frail and those with zero criteria as robust. Arterial stiffness was measured by aortic pulse wave velocity (aPWV). The data were analyzed using the generalized linear model.

RESULTS

From 249 participants (66.1 ± 5.3 years; 79.5% females), 61.8% (n = 154) were pre-frail and 38.2% (n = 95) robust. Pre-frail older adults had a higher aPWV (β = 0.19 m/s; p = 0.007) compared to their robust peers.

CONCLUSIONS

The pre-frailty phenotype was associated with higher arterial stiffness in community-dwelling older adults aged 60-80 years. Pre-frail older adults may have a higher risk for CVD.

Central hypertension is a non-negligible cardiovascular risk factor

High blood pressure (BP) confers cardiovascular risk. However, the clinical value of central BP remains debatable. In this article, we aim to briefly review the prognosis, diagnosis, and treatment of central hypertension. Central and brachial BPs are closely correlated. In most prospective investigations, elevated central and peripheral BPs were similarly associated with adverse outcomes. Outcome-driven thresholds of the central systolic BP estimated by the type I device were on average 10 mmHg lower than their brachial counterparts. Cross-classification based on the central and brachial BPs identified that nearly 10% of patients had discrepancy in their status of central and brachial hypertension. Irrespective of the brachial BP status, central hypertension was associated with increased cardiovascular risk, highlighting the importance of central BP assessment in the management of hypertensive patients. Newer antihypertensive agents, such as renin-angiotensin-aldosterone system inhibitors and calcium channel blockers, were more efficacious than older agents in central BP reduction. Clinical trials are warranted to demonstrate whether controlling central hypertension with an optimized antihypertensive drug treatment will be beneficial beyond the control of brachial hypertension.

Associations of office brachial blood pressure, office central blood pressure, and home brachial blood pressure with arterial stiffness

Accurate blood pressure (BP) measurement is necessary for the evaluation and treatment of hypertension to prevent the progression of subclinical vascular disease, including arterial stiffness. We investigated the associations between brachial-ankle pulse wave velocity (baPWV), a measure of arterial stiffness, and each of office brachial systolic BP (SBP) with and without an observer present (attended or unattended office brachial SBP), attended or unattended office central SBP, and home brachial SBPs (specifically, the means of morning, evening, or morning-evening home brachial SBP) in patients being treated for hypertension. Measurements were performed among 70 adults (mean age, 67.0 ± 9.4 years; women, 51.4%) with a mean attended office brachial SBP of 127.6 ± 14.5 mmHg and mean baPWV of 16.3 ± 2.8 m/s. Univariate analysis showed that higher attended office brachial SBP, morning home brachial SBP, and morning-evening home brachial SBP were each statistically significantly associated with higher baPWV (r = 0.25, P = 0.04; r = 0.37, P = 0.002; and r = 0.32, P = 0.006, respectively). Multiple linear regression analysis with adjustments for traditional cardiovascular risk factors showed that only morning home brachial SBP was statistically significantly associated with baPWV [β = 0.06, 95% confidence interval (0.01-0.11), P = 0.02). In conclusion, higher morning home brachial SBP - but none of the office-measured SBP values - was associated with arterial stiffness.

Risk Stratification by Cross-Classification of Central and Brachial Systolic Blood Pressure

BACKGROUND

Whether cardiovascular risk is more tightly associated with central (cSBP) than brachial (bSBP) systolic pressure remains debated, because of their close correlation and uncertain thresholds to differentiate cSBP into normotension versus hypertension.

METHODS

In a person-level meta-analysis of the International Database of Central Arterial Properties for Risk Stratification (n=5576; 54.1% women; mean age 54.2 years), outcome-driven thresholds for cSBP were determined and whether the cross-classification of cSBP and bSBP improved risk stratification was explored. cSBP was tonometrically estimated from the radial pulse wave using SphygmoCor software.

RESULTS

Over 4.1 years (median), 255 composite cardiovascular end points occurred. In multivariable bootstrapped analyses, cSBP thresholds (in mm Hg) of 110.5 (95% CI, 109.1-111.8), 120.2 (119.4-121.0), 130.0 (129.6-130.3), and 149.5 (148.4-150.5) generated 5-year cardiovascular risks equivalent to the American College of Cardiology/American Heart Association bSBP thresholds of 120, 130, 140, and 160. Applying 120/130 mm Hg as cSBP/bSBP thresholds delineated concordant central and brachial normotension (43.1%) and hypertension (48.2%) versus isolated brachial hypertension (5.0%) and isolated central hypertension (3.7%). With concordant normotension as reference, the multivariable hazard ratios for the cardiovascular end point were 1.30 (95% CI, 0.58-2.94) for isolated brachial hypertension, 2.28 (1.21-4.30) for isolated central hypertension, and 2.02 (1.41-2.91) for concordant hypertension. The increased cardiovascular risk associated with isolated central and concordant hypertension was paralleled by cerebrovascular end points with hazard ratios of 3.71 (1.37-10.06) and 2.60 (1.35-5.00), respectively.

CONCLUSIONS

Irrespective of the brachial blood pressure status, central hypertension increased cardiovascular and cerebrovascular risk indicating the importance of controlling central hypertension.

The International Database of Central Arterial Properties for Risk Stratification: Research Objectives and Baseline Characteristics of Participants

OBJECTIVE

To address to what extent central hemodynamic measurements, improve risk stratification, and determine outcome-based diagnostic thresholds, we constructed the International Database of Central Arterial Properties for Risk Stratification (IDCARS), allowing a participant-level meta-analysis. The purpose of this article was to describe the characteristics of IDCARS participants and to highlight research perspectives.

METHODS

Longitudinal or cross-sectional cohort studies with central blood pressure measured with the SphygmoCor devices and software were included.

RESULTS

The database included 10,930 subjects (54.8% women; median age 46.0 years) from 13 studies in Europe, Africa, Asia, and South America. The prevalence of office hypertension was 4,446 (40.1%), of which 2,713 (61.0%) were treated, and of diabetes mellitus was 629 (5.8%). The peripheral and central systolic/diastolic blood pressure averaged 129.5/78.7 mm Hg and 118.2/79.7 mm Hg, respectively. Mean aortic pulse wave velocity was 7.3 m per seconds. Among 6,871 participants enrolled in 9 longitudinal studies, the median follow-up was 4.2 years (5th-95th percentile interval, 1.3-12.2 years). During 38,957 person-years of follow-up, 339 participants experienced a composite cardiovascular event and 212 died, 67 of cardiovascular disease.

CONCLUSIONS

IDCARS will provide a unique opportunity to investigate hypotheses on central hemodynamic measurements that could not reliably be studied in individual studies. The results of these analyses might inform guidelines and be of help to clinicians involved in the management of patients with suspected or established hypertension.

New Method to Estimate Central Systolic Blood Pressure From Peripheral Pressure: A Proof of Concept and Validation Study

Objective: The non-invasive estimation of central systolic blood pressure (cSBP) is increasingly performed using new devices based on various pulse acquisition techniques and mathematical analyses. These devices are most often calibrated assuming that mean (MBP) and diastolic (DBP) BP are essentially unchanged when pressure wave travels from aorta to peripheral artery, an assumption which is evidence-based. We tested a new empirical formula for the direct central blood pressure estimation of cSBP using MBP and DBP only (DCBP = MBP²/DBP).

Methods and Results: First, we performed a post-hoc analysis of our prospective invasive high-fidelity aortic pressure database (n = 139, age 49 ± 12 years, 78% men). The cSBP was 146.0 ± 31.1 mmHg. The error between aortic DCBP and cSBP was −0.9 ± 7.4 mmHg, and there was no bias across the cSBP range (82.5–204.0 mmHg). Second, we analyzed 64 patients from two studies of the literature in whom invasive high-fidelity pressures were simultaneously obtained in the aorta and brachial artery. The weighed mean error between brachial DCBP and cSBP was 1.1 mmHg. Finally, 30 intensive care unit patients equipped with fluid-filled catheter in the radial artery were prospectively studied. The cSBP (115.7 ± 18.2 mmHg) was estimated by carotid tonometry. The error between radial DCBP and cSBP was −0.4 ± 5.8 mmHg, and there was no bias across the range.

Conclusion: Our study shows that cSBP could be reliably estimated from MBP and DBP only, provided BP measurement errors are minimized. DCBP may have implications for assessing cardiovascular risk associated with cSBP on large BP databases, a point that deserves further studies.

Twenty-Four-Hour Central (Aortic) Systolic Blood Pressure: Reference Values and Dipping Patterns in Untreated Individuals

Supplemental Digital Content is available in the text.

Central (aortic) systolic blood pressure (cSBP) is the pressure seen by the heart, the brain, and the kidneys. If properly measured, cSBP is closer associated with hypertension-mediated organ damage and prognosis, as compared with brachial SBP (bSBP). We investigated 24-hour profiles of bSBP and cSBP, measured simultaneously using Mobilograph devices, in 2423 untreated adults (1275 women; age, 18–94 years), free from overt cardiovascular disease, aiming to develop reference values and to analyze daytime-nighttime variability. Central SBP was assessed, using brachial waveforms, calibrated with mean arterial pressure (MAP)/diastolic BP (cSBP_MAP/DBPcal), or bSBP/diastolic blood pressure (cSBP_SBP/DBPcal), and a validated transfer function, resulting in 144 509 valid brachial and 130 804 valid central measurements. Averaged 24-hour, daytime, and nighttime brachial BP across all individuals was 124/79, 126/81, and 116/72 mm Hg, respectively. Averaged 24-hour, daytime, and nighttime values for cSBP_MAP/DBPcal were 128, 128, and 125 mm Hg and 115, 117, and 107 mm Hg for cSBP_SBP/DBPcal, respectively. We pragmatically propose as upper normal limit for 24-hour cSBP_MAP/DBPcal 135 mm Hg and for 24-hour cSBP_SBP/DBPcal 120 mm Hg. bSBP dipping (nighttime-daytime/daytime SBP) was −10.6 % in young participants and decreased with increasing age. Central SBP_SBP/DBPcal dipping was less pronounced (−8.7% in young participants). In contrast, cSBP_MAP/DBPcal dipping was completely absent in the youngest age group and less pronounced in all other participants. These data may serve for comparison in various diseases and have potential implications for refining hypertension diagnosis and management. The different dipping behavior of bSBP versus cSBP requires further investigation.

The effectiveness and safety of isometric resistance training for adults with high blood pressure: a systematic review and meta-analysis

High blood pressure (BP) is a global health challenge. Isometric resistance training (IRT) has demonstrated antihypertensive effects, but safety data are not available, thereby limiting its recommendation for clinical use. We conducted a systematic review of randomized controlled trials comparing IRT to controls in adults with elevated BP (systolic ≥130 mmHg/diastolic ≥85 mmHg). This review provides an update to office BP estimations and is the first to investigate 24-h ambulatory BP, central BP, and safety. Data were analyzed using a random-effects meta-analysis. We assessed the risk of bias with the Cochrane risk of bias tool and the quality of evidence with GRADE. Twenty-four trials were included (n = 1143; age = 56 ± 9 years, 56% female). IRT resulted in clinically meaningful reductions in office systolic (-6.97 mmHg, 95% CI -8.77 to -5.18, p < 0.0001) and office diastolic BP (-3.86 mmHg, 95% CI -5.31 to -2.41, p < 0.0001). Novel findings included reductions in central systolic (-7.48 mmHg, 95% CI -14.89 to -0.07, p = 0.035), central diastolic (-3.75 mmHg, 95% CI -6.38 to -1.12, p = 0.005), and 24-h diastolic (-2.39 mmHg, 95% CI -4.28 to -0.40, p = 0.02) but not 24-h systolic BP (-2.77 mmHg, 95% CI -6.80 to 1.25, p = 0.18). These results are very low/low certainty with high heterogeneity. There was no significant increase in the risk of IRT, risk ratio (1.12, 95% CI 0.47 to 2.68, p = 0.8), or the risk difference (1.02, 95% CI 1.00 to 1.03, p = 0.13). This means that there is one adverse event per 38,444 bouts of IRT. IRT appears safe and may cause clinically relevant reductions in BP (office, central BP, and 24-h diastolic). High-quality trials are required to improve confidence in these findings. PROSPERO (CRD42020201888); OSF ( https://doi.org/10.17605/OSF.IO/H58BZ ).

Relative and Absolute Risk to Guide the Management of Pulse Pressure, an Age-Related Cardiovascular Risk Factor

BACKGROUND

Pulse pressure (PP) reflects the age-related stiffening of the central arteries, but no study addressed the management of the PP-related risk over the human lifespan.

METHODS

In 4,663 young (18-49 years) and 7,185 older adults (≥50 years), brachial PP was recorded over 24 hours. Total mortality and all major cardiovascular events (MACEs) combined were coprimary endpoints. Cardiovascular death, coronary events, and stroke were secondary endpoints.

RESULTS

In young adults (median follow-up, 14.1 years; mean PP, 45.1 mm Hg), greater PP was not associated with absolute risk; the endpoint rates were ≤2.01 per 1,000 person-years. The adjusted hazard ratios expressed per 10-mm Hg PP increments were less than unity (P ≤ 0.027) for MACE (0.67; 95% confidence interval [CI], 0.47-0.96) and cardiovascular death (0.33; 95% CI, 0.11-0.75). In older adults (median follow-up, 13.1 years; mean PP, 52.7 mm Hg), the endpoint rates, expressing absolute risk, ranged from 22.5 to 45.4 per 1,000 person-years and the adjusted hazard ratios, reflecting relative risk, from 1.09 to 1.54 (P < 0.0001). The PP-related relative risks of death, MACE, and stroke decreased >3-fold from age 55 to 75 years, whereas absolute risk rose by a factor 3.

CONCLUSIONS

From 50 years onwards, the PP-related relative risk decreases, whereas absolute risk increases. From a lifecourse perspective, young adulthood provides a window of opportunity to manage risk factors and prevent target organ damage as forerunner of premature death and MACE. In older adults, treatment should address absolute risk, thereby extending life in years and quality.

Patient preferences for ambulatory blood pressure monitoring devices: Wrist-type or arm-type?

BACKGROUND

Ambulatory blood pressure monitoring (ABPM) is important in evaluating average 24-hour blood pressure (BP) levels, circadian rhythm, sleeping BP and BP variability but many patients are reluctant to use standard ABPM devices.

METHODS

We compared two validated ABPM devices, the BPro tonometric wrist monitor and the A&D TM-2430 oscillometric upper arm monitor, for agreement of recordings and acceptability in 37 hypertensive patients (aged 55±9 years).

RESULTS

Successful BP measurements were less frequent with the wrist-type than the arm-type device during the sleeping (66.3% vs. 92.9%, P <0.01) and awake periods (56.2% vs. 86.5%, P <0.01). Comparable paired readings showed no significant difference in systolic BP but diastolic BP (DBP) values were higher with the wrist compared to the arm monitor (24-hour 89±13 vs. 85±14 mmHg, P <0.01) with similar differences awake and sleeping. Bland-Altman analysis showed some large discrepancies between individual arm and wrist monitor measurements. More patients found the wrist monitor more comfortable to use than the arm monitor.

CONCLUSIONS

Despite the difference in individual BP measurements and the systematic overestimation of DBP values with the BPro device, wrist monitors with good patient acceptability may be useful to facilitate ABPM in some patients to provide additional information about cardiovascular risk and response to antihypertensive therapies.

Comparison of Brachial Blood Pressure and Central Blood Pressure in Attended, Unattended, and Unattended Standing Situations

Central systolic blood pressure (cSBP) is an independent predictor of future cardiovascular disease. Unattended brachial SBP (bSBP) can eliminate the white-coat effect. However, unattended cSBP and unattended standing cSBP have never been reported. We aimed to compare bSBP and cSBP in attended, unattended, and unattended standing situations. We also aimed to compare the white-coat effect and unattended orthostatic BP change between bSBP and cSBP. Altogether, 104 hypertensive outpatients were included (mean age: 66.0 ± 9.8 years, 41.3% male, mean body mass index: 25.0 ± 4.5). Attended bSBP/cSBP values were 127.3 ± 15.7/119.2 ± 15.0, unattended bSBP/cSBP values were 122.7 ± 15.3/114.4 ± 15.1, and unattended standing bSBP/cSBP values were 123.6 ± 15.7/114.1 ± 14.8 mmHg (correlation coefficients/coefficients of determination between bSBP and cSBP: 0.971/0.943, 0.970/0.941, and 0.964/0.929, respectively; all p < 0.001). No significant difference was observed in the white-coat effect between bSBP and cSBP (4.6 ± 5.8 vs. 4.8 ± 5.7 mmHg). Although there was no significant difference between unattended sitting SBP and unattended standing SBP in terms of both bSBP and cSBP, a numerically small but significant difference was observed in the unattended orthostatic BP change between bSBP and cSBP (0.9 ± 8.0 vs. -0.3 ± 9.0 mmHg, p = 0.002). In conclusion, significant and strong correlations were observed between bSBP and cSBP in attended, unattended, and unattended standing BP measurements. The white-coat effect on bSBP was equivalent to that on cSBP. There was a numerically small but significant difference in the unattended orthostatic BP change between bSBP and cSBP.

Acute glucose influx-induced mitochondrial hyperpolarization inactivates myosin phosphatase as a novel mechanism of vascular smooth muscle contraction

It is well-established that long-term exposure of the vasculature to metabolic disturbances leads to abnormal vascular tone, while the physiological regulation of vascular tone upon acute metabolic challenge remains unknown. Here, we found that acute glucose challenge induced transient increases in blood pressure and vascular constriction in humans and mice. Ex vivo study in isolated thoracic aortas from mice showed that glucose-induced vascular constriction is dependent on glucose oxidation in vascular smooth muscle cells. Specifically, mitochondrial membrane potential (ΔΨm), an essential component in glucose oxidation, was increased along with glucose influx and positively regulated vascular smooth muscle tone. Mechanistically, mitochondrial hyperpolarization inhibited the activity of myosin light chain phosphatase (MLCP) in a Ca2+-independent manner through activation of Rho-associated kinase, leading to cell contraction. However, ΔΨm regulated smooth muscle tone independently of the small G protein RhoA, a major regulator of Rho-associated kinase signaling. Furthermore, myosin phosphatase target subunit 1 (MYPT1) was found to be a key molecule in mediating MLCP activity regulated by ΔΨm. ΔΨm positively phosphorylated MYPT1, and either knockdown or knockout of MYPT1 abolished the effects of glucose in stimulating smooth muscle contraction. In addition, smooth muscle-specific Mypt1 knockout mice displayed blunted response to glucose challenge in blood pressure and vascular constriction and impaired clearance rate of circulating metabolites. These results suggested that glucose influx stimulates vascular smooth muscle contraction via mitochondrial hyperpolarization-inactivated myosin phosphatase, which represents a novel mechanism underlying vascular constriction and circulating metabolite clearance.

The Influence of Resting Heart Rate on Central Pulse Pressure is Age-Dependent

INTRODUCTION

Low resting heart rate (RHR) increases augmentation pressure (AP) and central pulse pressure (central PP) and decreases peripheral pressure wave amplification. Given that the contribution of AP to central PP increases with age we hypothesized that the influence of RHR on AP, central PP and peripheral amplification varies with age.

AIM

To evaluate the interaction between age and RHR on the forward and backward components of central PP.

METHODS

A cohort of 1249 ambulatory hypertensive patients with good quality radial wave recordings was stratified into age groups and quartiles of RHR (< 61, 61-68, 69-76 and > 76 bpm). Central aortic pressure was estimated from radial applanation tonometry.

RESULTS

Forward wave (FW) and AP showed opposite changes until midlife, mutually canceling their effect on central PP, whereas both components of central PP increased in parallel after the fifth decade. The initial fall in FW was expressed in the brachial artery as a corresponding decrease in PP and in peripheral amplification. After midlife there was a further decrease in peripheral amplification at the expense of the rise in central PP. A lower RHR exaggerated the age-related increase in left ventricular ejection time (LVET), AP, central PP, and the decrease in peripheral amplification (P < 0.001, for all the interactions between decades and quartiles of RHR). Multivariable regression analyses (n = 1249) confirmed a significant interaction between age and RHR on central PP (P < 0.001), AP (P < 0.001), LVET (P < 0.001), AIx (P < 0.035), and peripheral amplification (P < 0.001). Multivariable regression analyses stratified by age groups (< 30, 30-59 and ≥ 60 years) showed an increasing strength in the relationship of RHR with AP, independently of sex, mean arterial pressure, pulse wave velocity and beta-blockers use. The average increase in AP for a decrease in 10 bpm was 1.4 mmHg before age < 30 years; 2.5 mmHg between age 30-59 years; and 5.4 mmHg at 60 years and older.

CONCLUSIONS

A lower heart rate exaggerated AP and central PP in an age dependent fashion, being the effect particularly relevant in older patients.

Prediction of Cardiovascular Events by Type I Central Systolic Blood Pressure: A Prospective Study

Supplemental Digital Content is available in the text.

Compared with brachial blood pressure (BP), central systolic BP (SBP) can provide a better indication of the hemodynamic strain inflicted on target organs, but it is unclear whether this translates into improved cardiovascular risk stratification. We aimed to assess which of central or brachial BP best predicts cardiovascular risk and to identify the central SBP threshold associated with increased risk of future cardiovascular events. This study included 13 461 participants of CARTaGENE with available central BP and follow-up data from administrative databases but without cardiovascular disease or antihypertensive medication. Central BP was estimated by radial artery tonometry, calibrated for brachial SBP and diastolic BP (type I), and a generalized transfer function (SphygmoCor). The outcome was major adverse cardiovascular events. Cox proportional-hazards models, differences in areas under the curves, net reclassification indices, and integrated discrimination indices were calculated. Youden index was used to identify SBP thresholds. Over a median follow-up of 8.75 years, 1327 major adverse cardiovascular events occurred. The differences in areas under the curves, net reclassification indices, and integrated discrimination indices were of 0.2% ([95% CI, 0.1–0.3] P<0.01), 0.11 ([95% CI, 0.03–0.20] P=0.01), and 0.0004 ([95% CI, −0.0001 to 0.0014] P=0.3), all likely not clinically significant. Central and brachial SBPs of 112 mm Hg (95% CI, 111.2–114.1) and 121 mm Hg (95% CI, 120.2–121.9) were identified as optimal BP thresholds. In conclusion, central BP measured with a type I device is statistically but likely not clinically superior to brachial BP in a general population without prior cardiovascular disease. Based on the risk of major adverse cardiovascular events, the optimal type I central SBP appears to be 112 mm Hg.