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The influence of SBP amplification on the accuracy of form-factor-derived mean arterial pressure


Schultz, MG and Picone, DS and Armstrong, MK and Black, JA and Dwyer, N and Roberts-Thomson, P and Sturgess, D and Sharman, JE, The influence of SBP amplification on the accuracy of form-factor-derived mean arterial pressure, Journal of Hypertension, 38, (6) pp. 1033-1039. ISSN 0263-6352 (2020) [Refereed Article]

Copyright Statement

Copyright 2020 Wolters Kluwer Health, Inc. All rights reserved.

DOI: doi:10.1097/HJH.0000000000002385


Objectives: Accurate assessment of mean arterial pressure (MAP) is crucial in research and clinical settings. Measurement of MAP requires not only pressure waveform integration but can also be estimated via form-factor equations incorporating peripheral SBP. SBP may increase variably from central-to-peripheral arteries (SBP amplification), and could influence accuracy of form-factor-derived MAP, which we aimed to determine.

Methods: One hundred and eighty-eight patients (69% men, age 60 10 years) undergoing coronary angiography had intra-arterial pressure measured in the ascending aorta, brachial and radial arteries. Reference MAP was measured by waveform integration, and form-factor-derived MAP using 33 and 40% form-factors.

Results: Reference MAP decreased from the aorta to the brachial (-0.7 4.2 mmHg) and radial artery (-1.7 4.8 mmHg), whereas form-factor-derived MAP increased (33% form-factor 1.1 4.2 and 1.7 4.7 mmHg; 40% form-factor 0.9 4.8 and 1.4 5.4 mmHg, respectively). Form-factor-derived MAP was significantly different to reference aortic MAP (33% form-factor -2.5 4.6 and -1.6 5.8, P < 0.001; 40% form-factor 2.5 5.0 and 3.9 6.4 mmHg, P < 0.001, brachial and radial arteries, respectively), with significant variation in the brachial form-factor required (FFreq) to generate MAP equivalent to reference aortic MAP (FFreq range 20-57% brachial; 17-74% radial). Aortic-to-brachial SBP amplification was strongly related to brachial FFreq (r = -0.695, P < 0.001). The 33% form-factor was most accurate with high aortic-to-brachial SBP amplification (33% form-factor MAP vs. reference aortic MAP difference 0.06 3.93 mmHg, P = 0.89) but overestimated reference aortic MAP with low aortic-to-brachial SBP amplification (+5.8 4.6 mmHg, P < 0.001). The opposite was observed for the 40% form-factor.

Conclusion: Due to variable SBP amplification, estimating MAP via form-factors produces nonphysiological inaccurate values. These findings have important implications for accurate assessment of MAP in research and clinical settings.

Item Details

Item Type:Refereed Article
Keywords:amplification, artery, blood pressure, haemodynamic monitoring, homeostasis
Research Division:Biomedical and Clinical Sciences
Research Group:Cardiovascular medicine and haematology
Research Field:Cardiology (incl. cardiovascular diseases)
Objective Division:Health
Objective Group:Clinical health
Objective Field:Clinical health not elsewhere classified
UTAS Author:Schultz, MG (Dr Martin Schultz)
UTAS Author:Picone, DS (Dr Dean Picone)
UTAS Author:Armstrong, MK (Mr Matthew Armstrong)
UTAS Author:Black, JA (Dr Andrew Black)
UTAS Author:Dwyer, N (Dr Nathan Dwyer)
UTAS Author:Roberts-Thomson, P (Dr Philip Roberts-Thomson)
UTAS Author:Sharman, JE (Professor James Sharman)
ID Code:139258
Year Published:2020
Web of Science® Times Cited:6
Deposited By:Menzies Institute for Medical Research
Deposited On:2020-06-03
Last Modified:2021-03-24

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