Closer to Noninvasive Out-of-Office Aortic Blood Pressure Assessment

Abstract

See related article, pp 825-832T he noninvasive assessment of central (aortic or carotid) blood pressure (BP) is a challenge to the clinical investigation of arterial hypertension. The importance of central BP was recognized decades ago on the basis of invasive hemodynamic studies 1 but has become widely acknowledged during the last 15 years. 2 This is largely attributed to the work of highly respected pioneers, like Michael O'Rourke's team, who created the first commercial device (SphygmoCor, AtCor, Sydney, Australia), enabling the wide application of the noninvasive assessment of aortic BP. 3 In this issue of Hypertension, Weber et al 4 present the validation of a novel BP recording device that noninvasively assesses aortic BP based on the brachial cuff oscillometric method and the application of mathematical transformation. The present invasive and noninvasive validation is of importance because it is a straightforward demonstration of the strengths and disadvantages of a new generation of BP devices that opens the way to out-of-office aortic BP selfassessment. After briefly reviewing the reasons for estimating central BP, we discuss the novelty of this device, the findings, and limitations of this study. 4 and some of the major issues that should arise in future clinical research and practice. Why Assess Central Pressure?The reasons have been extensively addressed in recent expert opinions and reviews 1,5 and are only summarized here. Normally, central systolic BP (SBP) and pulse pressure (PP) are lower than peripheral SBP and PP (from 1 to 30 mm Hg). This PP disparity, defined as PP amplification, 1 is an undisputable physiological phenomenon and depends on the individual's hemodynamic and pathophysiological characteristics. 1,6 Notably, PP amplification exhibits substantial within-subject time variability (eg, from 5 to 20 mm Hg; Figure) that is mainly attributed to variations in heart rate, pressure wave reflections, and arterial elasticity/diameter. 1 The closer physiological relevance of central PP over brachial PP to cardiovascular disease/events is supported by published data. 5,7 Both nonpharmacological and pharmacological interventions have clinically important effects on PP amplification, that is, on central PP rather than brachial PP, 1,8 and potentially on cardiovascular outcomes. 1,5 The above published data are derived from studies in laboratories and clinic settings; it is likely that out-of-office assessment of central BP or PP amplification will improve the models of cardiovascular risk assessment currently based solely on brachial BP. Comment on the Novelty of the New DeviceIn the present study, a previously validated automatic oscillometric device for 24-hour ambulatory brachial BP recording (Mobilo-O-Graph NG, IEM, Stolberg, Germany) 9 has been upgraded to record brachial waveforms and mathematically transform them by software analysis to aortic waveforms. These noninvasive data were validated to assess the aortic BP. The novelty of this application is the use of the brachial cuff instead...

Ambulatory Recording of Wave Reflections and Arterial Stiffness during Intra- and Interdialytic Periods in Patients Treated with Dialysis

“…First, Mobil-O-Graph records brachial BP and pulse waves using the oscillometric method; although this differs from the most widely applied technique of applanation tonometry (23), previous validation studies in different populations (including patients with ESRD) showed acceptable agreement between Mobil-O-Graph-derived variables and invasive and noninvasive measurements (23,24,28,30,31). Second, because this was a pilot study, no power estimation was performed before its initiation; we believe, however, that the number of participants, together with the high number of readings (.120) during the 48-hour recordings, provided adequate power.…”

“…A newly introduced ABPM device (Mobil-O-Graph; IEM, Stolberg, Germany) records oscillometric BP and pulse waveforms at the brachial artery and provides valid measures of aortic BP, AIx, and PWV in ambulatory conditions (22)(23)(24). This study aimed to investigate for the first time the variation of central BP, AIx, and PWV during 48-hour ABPM in hemodialysis patients in order to compare differences in these indices between in-dialysis and out-of-dialysis periods and explore associations of demographic, clinical, and hemodynamic parameters with ambulatory AIx and PWV.…”

Association of left ventricular diastolic dysfunction with 24-h aortic ambulatory blood pressure: the SAFAR study

“…[8][9][10][11] Our recent publication proved that, as compared with 24-h brachial AMBP, 24-h aortic ABPM is better associated with left ventricular hypertrophy. 12 The aim of the present analysis, within the context…”

“…[8][9][10][11] Our recent publication proved that, as compared with 24-h brachial AMBP, 24-h aortic ABPM is better associated with left ventricular hypertrophy. 12 The aim of the present analysis, within the context of the 'Non-invaSive Aortic ambulatory blood pressure monitoring For the detection of tARget organ damage (SAFAR)' study, was to investigate the hypothesis that LVDD is better associated with 24-h aortic BP, than office (brachial and aortic) BP and 24-h brachial BP.…”

Evaluation of a Novel Brachial Cuff-Based Oscillometric Method for Estimating Central Systolic Pressure in Hemodialysis Patients

“…A newly introduced brachial cuff-based oscillometric ABPM device (Mobil-O-Graph, IEM, Stolberg, Germany) records BP and pulse waveforms at the brachial artery and estimates aortic BP, augmentation index (AIx) and pulse wave velocity (PWV) in the ambulatory setting [15,16]. However, this device has major methodological differences from the currently applied tonometry-based methods, raising the issue of investigating its validity.…”