The prevalence of central hypertension defined by a central blood pressure type I device and its association with target organ damage in the community-dwelling elderly Chinese: The Northern Shanghai Study

Wave reflection quantification analysis and personalized flow wave estimation based on the central aortic pressure waveform

Pulse wave reflections reflect cardiac afterload and perfusion, which yield valid indicators for monitoring cardiovascular status. Accurate quantification of pressure wave reflections requires the measurement of aortic flow wave. However, direct flow measurement involves extra equipment and well-trained operator. In this study, the personalized aortic flow waveform was estimated from the individual central aortic pressure waveform (CAPW) based on pressure-flow relations. The separated forward and backward pressure waves were used to calculate wave reflection indices such as reflection index (RI) and reflection magnitude (RM), as well as the central aortic pulse transit time (PTT). The effectiveness and feasibility of the method were validated by a set of clinical data (13 participants) and the Nektar1D Pulse Wave Database (4,374 subjects). The performance of the proposed personalized flow waveform method was compared with the traditional triangular flow waveform method and the recently proposed lognormal flow waveform method by statistical analyses. Results show that the root mean square error calculated by the personalized flow waveform approach is smaller than that of the typical triangular and lognormal flow methods, and the correlation coefficient with the measured flow waveform is higher. The estimated personalized flow waveform based on the characteristics of the CAPW can estimate wave reflection indices more accurately than the other two methods. The proposed personalized flow waveform method can be potentially used as a convenient alternative for the measurement of aortic flow waveform.

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.

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.

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.

Pulse Wave Calibration and Implications for Blood Pressure Measurement: Systematic Review and Meta-Analysis

[Figure: see text].

Contribution of single office aortic systolic blood pressure measurements to the detection of masked hypertension: data from two separate cohorts

Masked hypertension (MH) and masked uncontrolled hypertension (MUH) remain largely underdiagnosed with no efficient detection algorithm. We recently proposed a novel classification of office systolic hypertension phenotypes defined on the basis of both brachial and aortic systolic blood pressure (bSBP/aSBP) and showed that type III ("isolated high office aSBP" phenotype: normal office bSBP but high office aSBP) has higher hypertension-mediated organ damage (HMOD). We tested whether MH/MUH (1) can be detected with the "isolated high office aSBP" phenotype and (2) if it is associated with elevated office aSBP with respect to normotension. We classified two separate and quite different cohorts (n = 391 and 956, respectively) on the basis of both bSBP and aSBP into four different phenotypes. Participants were classified as sustained hypertensives, masked hypertensives/masked uncontrolled hypertensives (MHs/MUHs), white coat hypertensives, and normotensives according to their office and out-of-office BP readings. The majority (more than 60% in cohort A and more than 50% in cohort B) of type III individuals were MHs/MUHs. Almost 35% of MHs/MUHs had optimal office bSBP rather than high normal bSBP. In both cohorts, the detection of more than 40% of MH/MUH was feasible with the type III phenotype. MHs/MUHs had higher office aSBP than individuals with sustained normotension (p < 0.05). In conclusion, in the absence of an efficient screening test, the diagnosis of MH/MUH can be assisted by the detection of the "isolated high office aSBP" phenotype, which can be measured in a single office visit. MHs/MUHs have increased aSBP relative to normotensives, further explaining the increased mortality of MH/MUH.

Ambulatory blood pressure phenotypes and isolated elevation of office central or brachial blood pressure

Disagreements in office brachial and central blood pressure (BP) have resulted in the identification of novel hypertension phenotypes, namely isolated central hypertension (ICH) and isolated brachial hypertension (IBH). This study investigated the relationship of ICH and IBH with ambulatory BP phenotypes among 753 individuals (mean age = 47.6 ± 15.2 years, 48% males) who underwent office and 24-hours brachial and central BP measures using a Mobil-O-Graph PWA monitor. Thresholds for elevated office central and brachial BP were 130/90 and 140/90 mm Hg. Results of multivariable analysis adjusted for potential confounders showed that ICH (n = 25) had 3.71-fold (95% CI 1.48-9.32; P = .005) greater risk of masked hypertension than normal brachial/central BP (n = 362), while IBH (n = 20) had 4.65-fold (95% CI 1.76-12.25; P = .002) greater risk of white coat hypertension compared with combined brachial/central hypertension (n = 346). These findings suggest that the diagnosis of ICH and IBH might be useful in identifying individuals at higher risk of presenting discordant office and ambulatory BP phenotypes.

Central blood pressure for the management of hypertension: Is it a practical clinical tool in current practice?

Since noninvasive central blood pressure (BP) measuring devices are readily available, central BP has gained growing attention regarding its clinical application in the management of hypertension. The disagreement between central and peripheral BP has long been recognized. Some previous studies showed that noninvasive central BP may be better than the conventional brachial BP in association with target organ damages and long-term cardiovascular outcomes. Recent studies further suggest that the central BP strategy for confirming a diagnosis of hypertension may be more cost-effective than the conventional strategy, and guidance of hypertension management with central BP may result in less use of medications to achieve BP control. Despite the use of central BP being promising, more randomized controlled studies comparing central BP-guided therapeutic strategies with conventional care for cardiovascular events reduction are required because noninvasive central and brachial BP measures are conveniently available. In this brief review, the rationale supporting the utility of central BP in clinical practice and relating challenges are summarized.

2019 Consensus of the Taiwan Hypertension Society and Taiwan Society of Cardiology on the Clinical Application of Central Blood Pressure in the Management of Hypertension

The Taiwan Society of Cardiology (TSOC) and the Taiwan Hypertension Society (THS) have appointed a joint consensus group for the 2019 Consensus of the TSOC and THS on the Clinical Application of Central blood pressure (BP) in the Management of Hypertension with the aim of formulating a management consensus on the clinical application of central BP in the management of hypertension. This consensus document focuses on the clinical application of central BP in the care of patients with hypertension. The major determinants of central BP are increased arterial stiffness and wave reflection, which are also the dominant hemodynamic manifestations of vascular aging. Central BP can be measured noninvasively using various techniques, including with convenient cuff-based oscillometric central BP monitors. Noninvasive central BP is better than conventional brachial BP to assess target organ damage and long-term cardiovascular outcomes. Based on the analysis of long-term events, a central BP threshold of 130/90 mmHg for defining hypertension has been proposed. Recent studies have suggested that a central BP strategy to confirm a diagnosis of hypertension may be more cost-effective than conventional strategies, and that guiding hypertension management with central BP may result in the use of fewer medications to achieve BP control. Although noninvasive measurements of brachial BP are inaccurate and central BP has been shown to carry superior prognostic value beyond brachial BP, the use of central BP should be justified in studies comparing central BP-guided therapeutic strategies with conventional care for cardiovascular events.