ASH Position Paper
American Society of Hypertension position paper: central blood pressure waveforms in health and disease

https://doi.org/10.1016/j.jash.2015.10.012Get rights and content

Abstract

A number of devices are available which noninvasively estimate central aortic blood pressure using a variety of approaches such as tonometry or oscillometry. In this position paper, we discuss how the central pressure waveform is generated and measured, how central pressure waveforms appear in health and disease, the predictive value of central blood pressure measurements, the effects of interventions on waveforms, and areas of future need in this field of clinical and research endeavor.

Introduction

There is a century-old tradition of indirect (noninvasive) measurement of the systolic blood pressure (SBP) and diastolic blood pressures (BPs) in the brachial artery, using a cuff, as an index of the hemodynamic state of the arterial circulation.1 However, BP is determined by a complex interaction of the pressure generated by the left ventricle (LV) and the impedance to blood flow exerted by the vasculature, and measurement of brachial cuff BP alone does not provide information as which of those two factors are predominant.2, 3 In addition, it is now understood that the SBP generated by the LV is further affected by reflected pressure waves from points of discontinuity in the arterial tree, such as bifurcations and abrupt decreases in vascular caliber.4, 5 Reflected waves modulate the arterial waveform at various points in the circulation, so that the pressures in the aorta are different (less) from those in more distal vessels, such as the brachial artery.5, 6 This is clearly important, as it is the properties of the arterial tree and aortic hemodynamics that constitute the input impedance (or afterload) to LV ejection and will therefore be a determinant of LV hypertrophy and myocardial oxygen demand.2, 3

Measurement of brachial SBP and diastolic BP alone provides only indirect information about the adequacy of tissue and organ perfusion. It does not tell us what the central aortic BP is and therefore the impedance to LV ejection. It does not tell us about the relative contributions to BP of LV ejection and of distal vascular stiffness and resistance. It also does not provide information about the quantitative role of reflected pressure waves in generating the central SBP. To further our understanding of the hemodynamics of the circulation, efforts over the last several decades have sought to noninvasively assess central aortic BP, and from an analysis of the arterial waveform to dissect out the relative contributions of LV ejection and wave reflection, and to discern the longitudinal effects of these interactions on organs supplied directly by the aorta, such as the myocardium, the kidney, and the brain.7

In this American Society of Hypertension sponsored position paper, we will review the physiology of the central aortic pressure waveform and how it is generated and measured, how it changes with aging and comorbidities, its predictive utility for target organ damage, the effects of medication on the waveform, and then conclude with some recommendations regarding areas of needed research in this aspect of clinical hemodynamic measurement.

Section snippets

Generation of the Central Aortic Pressure Waveform

The systemic arterial tree is made up of a system of distensible tubes along which pressure and flow waves, generated by LV ejection, are transmitted and reflected. Early recordings of ascending aortic pressure and flow waves, and pulse wave analysis (PWA), were obtained in the cardiac catheterization laboratory using high-fidelity multisensor (pressure and velocity) catheters.5 During one cardiac cycle, the generated wave has sufficient time to travel to the periphery and back.5 Pressure and

Measurement of the Central BP Wave

Because invasive recordings of central aortic pressure waves and PWA can only be made in a small number of selected patients in the catheterization laboratory, techniques have been developed that enable the noninvasive determination of the above variables18 in large cohorts with similar results.19 Some studies use the carotid artery pressure wave as a surrogate for the central aortic pressure wave, whereas others derive it from the radial or brachial artery pressure wave using a generalized

How Does the Central Aortic Pressure Waveform Appear in Health and Disease?

To understand how the central aortic pressure waveform appears in health (see Figure 1) and in various circulatory disorders, it is necessary to understand how the forces that shape the pressure waveform interact and what influences various disorders such as age, hypertension, diabetes, and hypercholesterolemia have on these influences. The contraction of the LV initiates the forward-traveling pressure wave (see Figure 1, Figure 2). Initially, for about 90 milliseconds, there is virtually no

How Predictive is the Central Aortic Pressure Waveform for Outcomes?

Multiple studies have assessed the prognostic value of the brachial artery or central aortic pressures. Vlachopoulos et al50 performed a meta-analysis of 11 longitudinal studies that used measures of central hemodynamics, including a total of 5648 subjects followed during a mean period of 45 months. The risk ratio for total cardiovascular (CV) events was found to increase by 8.8% for each 10 mm Hg increase in central systolic pressure and by 13.7% for each 10 mm Hg increase of central PP. When

Pharmacologic Interventions

Early acute studies showed that glyceryltrinitrate (GTN) differentially altered the aortic pressure waveform and lowered central SBP more than brachial SBP.61, 62, 63 Although concerns regarding tolerance and long-term efficacy of GTN have prevented the use of GTN for antihypertensive purposes, more conventional antihypertensive therapies also differentially affect central compared with brachial SBP. Several small studies suggested that beta blockade (primarily atenolol) was less effective in

Future Needs in Central Aortic Pressure Waveform Analysis

Randomized controlled trials in hypertension demonstrating the benefits of treatment on major CV outcomes have been based on brachial BP measurements, usually with either a mercury sphygmomanometer or a validated automated device. BP measured in this manner was used both for threshold or range of BP for eligibility to be entered into the trials and usually for the treatment goal(s) during the trials. Although, as described previously, some trials have measured central BP in a subgroup of

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  • Cited by (27)

    • Estimation of wave reflection in aorta from radial pulse waveform by artificial neural network: a numerical study

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      Citation Excerpt :

      Amplitude and arrival timing of reflected waves are two main aspects contributing to the augmentation of central systolic blood pressure, which has been demonstrated in patients with increased arterial stiffness, hypertension and aging [1–3]. This augmentation of systolic pressure caused by wave reflection results in the increase of left ventricular load, and thus increased myocardial oxygen demand, but reduced ejection fraction from the heart [4,5]. Therefore, the estimation or measurement of wave reflection is vitally important to monitor and evaluate the health of cardiovascular system.

    • Augmentation index in the assessment of wave reflections and systolic loading

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      It must be noted that the validation of these indices was based on brachial artery pressure measurements and the computations of the augmentation index and the reflection coefficient in our study have been based on central blood pressure measurements. It must also be acknowledged that there is a requirement for the broader consensus of the value of central blood pressure measurements [40]. However, the use of central blood pressure as an indicator of characteristic aortic impedance and arterial compliance has interesting applications in estimating arterial stiffness.

    • 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

      2018, Journal of the American Society of Hypertension
      Citation Excerpt :

      In the past, the noninvasive technique of measuring central BP was unavailable. But now, we can easily and noninvasively measure central BP through several methods and kinds of devices,26–30 just like measuring brachial BP. Furthermore, accumulating evidences based on these noninvasively estimated central BP have demonstrated that central BP is superior to brachial BP in predicting TOD2–5 and cardiovascular events and mortality.2,6–9

    • Reflection Magnitude, a Measure of Arterial Stiffness, Predicts Incident Heart Failure in Men But Not Women: Multi-Ethnic Study of Atherosclerosis (MESA)

      2017, Journal of Cardiac Failure
      Citation Excerpt :

      Radial applanation tonometry was performed on all participants at baseline (exam 1) with the use of an HDI/Pulsewave-CR2000 tonometry device (Hypertension Diagnostics, Eagan, Minnesota). Obtaining estimated central pressure waveforms with the use of radial applanation tonometry was previously described.16,17 Radial applanation tonometry uses a pressure sensor placed over the radial artery and applies a gentle pressure to slightly flatten (“applanate”) the vessel.

    • Response to Budoff and Steigerwalt

      2016, Journal of the American Society of Hypertension
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    Funding: R.R.T. received grants from NIH and Fukuda Denshi. D.G.E. received grants from NIH. J.A.C. received grants from NIH, American College of Radiology Network, and Fukuda Denshi. B.F. received grants from NIH, Department of Homeland Security, and the National Multiple Sclerosis Society. W.C.C. received grants from NIH, Merck, and Eli Lilly.

    Conflict of interest: R.R.T. is a consultant to Medtronic, Janssen, and GSK. C.R. has nothing to disclose. W.W.N. is a consultant for Millar Instruments Inc, Houston, Texas. J.A.C. is a consultant for OPKO Healthcare, Bristol-Myers Squibb, and Fukuda Denshi. B.F. received royalties from Human Kinetics Publishers.

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