P137 Reflections Revisited: Reinterpretation Required

Berend Westerhof; Nico Westerhof

doi:10.2991/artres.k.191224.160

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Volume 25, Issue Supplement 1, December 2019, Pages S175 - S175

P137 Reflections Revisited: Reinterpretation Required

Authors

Berend Westerhof¹^{, 2}^{, *}, Nico Westerhof¹

¹Department of Pulmonary Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands

²Department of Medical Biology, Section of Systems Physiology, Laboratory for Clinical Cardiovascular Physiology, Amsterdam UMC, University of Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands

^*Corresponding author. Email: berend.westerhof@gmail.com

Corresponding Author

Berend Westerhof

Available Online 17 February 2020.

DOI: 10.2991/artres.k.191224.160 How to use a DOI?
Abstract: Introduction: Pressure waveshape derived parameters such as the augmentation index are related to unfavourable cardiovascular events [1]. Wave reflections determine wave shape [2], however, several findings seem to contradict the current views. Current view. The arterial system can be modelled by a tube with a reflection site at the end: the heart sets up waves propagating down the system, reflecting at the end and returning to the heart after twice the travel time, i.e. aortic length over Pulse Wave Velocity (PWV).Data. Return time of the reflected wave is not inversely proportional to PWV [3]. Also, reflected waves appear to run downstream rather than to the heart [4]. These findings conflict with the current concepts.

Interpretation: At all locations in the arterial system, wave reflection is determined by the characteristic impedance of the supplying vessel and the input impedance of the downstream system. The input impedance results from a system of many arteries with multiple reflection sites [5]. Time delay between forward and reflected wave is mainly determined by the phase angle of the downstream impedance, and does not systematically increase or decrease with distance. This implies that the time difference between reflected and forward wave is not increasing towards the heart as assumed by the single-tube model. As a consequence, the return time of the reflected wave is not inversely proportional to PWV.

Conclusion: The single tube model should be abandoned as conceptual model as is does not explain the measured data. A frequency domain (impedance) model is required.
Copyright: © 2019 Association for Research into Arterial Structure and Physiology. Publishing services by Atlantis Press International B.V.
Open Access: This is an open access article distributed under the CC BY-NC 4.0 license (http://creativecommons.org/licenses/by-nc/4.0/).

References

[1]T Weber, J Auer, MF O’Rourke, E Kvas, E Lassnig, G Lamm, et al., Increased arterial wave reflections predict severe cardiovascular events in patients undergoing percutaneous coronary interventions, Eur Heart J, Vol. 26, 2005, pp. 2657-63.

[2]MF O’Rourke, A Adji, and ME Safar, Structure and function of systemic arteries: reflections on the arterial pulse, Am J Hypertens, Vol. 31, 2018, pp. 934-40.

[3]AJ Baksi, TA Treibel, JE Davies, N Hadjiloizou, RA Foale, KH Parker, et al., A meta-analysis of the mechanism of blood pressure change with aging, J Am Coll Cardiol, Vol. 54, 2009, pp. 2087-92.

[4]JV Tyberg, JC Bouwmeester, KH Parker, NG Shrive, and JJ Wang, The case for the reservoir-wave approach, Int J Cardiol, Vol. 172, 2014, pp. 299-306.

[5]MG Taylor, The input impedance of an assembly of randomly branching elastic tubes, Biophys J, Vol. 6, 1966, pp. 29-51.

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Journal: Artery Research
Volume-Issue: 25 - Supplement 1
Pages: S175 - S175
Publication Date: 2020/02/17
ISSN (Online): 1876-4401
ISSN (Print): 1872-9312
DOI: 10.2991/artres.k.191224.160 How to use a DOI?
Open Access: This is an open access article distributed under the CC BY-NC 4.0 license (http://creativecommons.org/licenses/by-nc/4.0/).

Cite this article

ris enw bib

TY  - JOUR
AU  - Berend Westerhof
AU  - Nico Westerhof
PY  - 2020
DA  - 2020/02/17
TI  - P137 Reflections Revisited: Reinterpretation Required
JO  - Artery Research
SP  - S175
EP  - S175
VL  - 25
IS  - Supplement 1
SN  - 1876-4401
UR  - https://doi.org/10.2991/artres.k.191224.160
DO  - 10.2991/artres.k.191224.160
ID  - Westerhof2020
ER  -

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