Discrepancy between in-vivo measure and ex-vivo calculation of pulse wave velocity in retinal arteries

Mahdieh Rezaeian; Arthur Leloup; Angela Schulz; Mojtaba Golzan; Stuart Graham; Alberto Avolio; Mark Butlin

doi:10.1016/j.artres.2018.10.041

Abstract

Background. Pulse wave velocity (PWV) in large arteries is a pressure-dependent marker of arterial stiffness. The retinal vasculature provides unique access to the microcirculation. There is inconsistency between reported values of retinal PWV (rPWV). The pressure dependency of rPWV was measured in-vivo and calculated ex-vivo using retinal artery material properties to investigate the inconsistencies. Methods. High-speed fundus videos (125 fps) from three Sprague Dawley rats were recorded simultaneously with electrocardiogram and blood pressure. rPWV was measured using the cardiac component of retinal artery diameter waveforms at two retinal sites across a physiological range (70-130 mmHg) of mean arterial pressure (MAP). Ex-vivo tensile testing was performed on bovine retinal arteries, rat retinal arteries being too small for myography. Diameter and wall thickness of the retinal artery adjacent to the optic disc were measured using optical coherence tomography. Tensile testing was performed using a wire myograph in 9 bovine retinal artery specimens. Results. In-vivo results showed a significant positive correlation between rPWV (4.9±1.8 mm/s) and MAP (R2=0.58, p0.001) as expected. Ex-vivo, calculated rPWV using material stiffness and geometry measurement ranged between 4.6 and 7.0 m/s at effective distending pressures between 70 and 100 mmHg. Conclusions. Ex-vivo and in-vivo results differed by three orders of magnitude but should be the same. Ex-vivo results are in the same order as measured in-vivo in large arteries. In-vivo rPWV was lower than expected yet was responsive to changes in MAP. Further studies are required to uncover what rPWV is a measurement of, if not arterial stiffness.

Original language	English
Article number	4.2
Pages (from-to)	75
Number of pages	1
Journal	Artery Research
Volume	24
Issue number	C
DOIs	https://doi.org/10.1016/j.artres.2018.10.041
Publication status	Published - Dec 2018
Event	Association for Research into Arterial Structure and Physiology Conference 2018 - Guimaraes, Portugal Duration: 18 Oct 2018 → 20 Oct 2018

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@article{d47da734cb85489cb54aa501e58bc5be,

title = "Discrepancy between in-vivo measure and ex-vivo calculation of pulse wave velocity in retinal arteries",

abstract = "Background. Pulse wave velocity (PWV) in large arteries is a pressure-dependent marker of arterial stiffness. The retinal vasculature provides unique access to the microcirculation. There is inconsistency between reported values of retinal PWV (rPWV). The pressure dependency of rPWV was measured in-vivo and calculated ex-vivo using retinal artery material properties to investigate the inconsistencies. Methods. High-speed fundus videos (125 fps) from three Sprague Dawley rats were recorded simultaneously with electrocardiogram and blood pressure. rPWV was measured using the cardiac component of retinal artery diameter waveforms at two retinal sites across a physiological range (70-130 mmHg) of mean arterial pressure (MAP). Ex-vivo tensile testing was performed on bovine retinal arteries, rat retinal arteries being too small for myography. Diameter and wall thickness of the retinal artery adjacent to the optic disc were measured using optical coherence tomography. Tensile testing was performed using a wire myograph in 9 bovine retinal artery specimens. Results. In-vivo results showed a significant positive correlation between rPWV (4.9±1.8 mm/s) and MAP (R2=0.58, p0.001) as expected. Ex-vivo, calculated rPWV using material stiffness and geometry measurement ranged between 4.6 and 7.0 m/s at effective distending pressures between 70 and 100 mmHg. Conclusions. Ex-vivo and in-vivo results differed by three orders of magnitude but should be the same. Ex-vivo results are in the same order as measured in-vivo in large arteries. In-vivo rPWV was lower than expected yet was responsive to changes in MAP. Further studies are required to uncover what rPWV is a measurement of, if not arterial stiffness.",

author = "Mahdieh Rezaeian and Arthur Leloup and Angela Schulz and Mojtaba Golzan and Stuart Graham and Alberto Avolio and Mark Butlin",

note = "Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.; Association for Research into Arterial Structure and Physiology Conference 2018, ARTERY 2018 ; Conference date: 18-10-2018 Through 20-10-2018",

year = "2018",

month = dec,

doi = "10.1016/j.artres.2018.10.041",

language = "English",

volume = "24",

pages = "75",

journal = "Artery Research",

issn = "1872-9312",

publisher = "Elsevier",

number = "C",

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TY - JOUR

T1 - Discrepancy between in-vivo measure and ex-vivo calculation of pulse wave velocity in retinal arteries

AU - Rezaeian, Mahdieh

AU - Leloup, Arthur

AU - Schulz, Angela

AU - Golzan, Mojtaba

AU - Graham, Stuart

AU - Avolio, Alberto

AU - Butlin, Mark

N1 - Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

PY - 2018/12

Y1 - 2018/12

N2 - Background. Pulse wave velocity (PWV) in large arteries is a pressure-dependent marker of arterial stiffness. The retinal vasculature provides unique access to the microcirculation. There is inconsistency between reported values of retinal PWV (rPWV). The pressure dependency of rPWV was measured in-vivo and calculated ex-vivo using retinal artery material properties to investigate the inconsistencies. Methods. High-speed fundus videos (125 fps) from three Sprague Dawley rats were recorded simultaneously with electrocardiogram and blood pressure. rPWV was measured using the cardiac component of retinal artery diameter waveforms at two retinal sites across a physiological range (70-130 mmHg) of mean arterial pressure (MAP). Ex-vivo tensile testing was performed on bovine retinal arteries, rat retinal arteries being too small for myography. Diameter and wall thickness of the retinal artery adjacent to the optic disc were measured using optical coherence tomography. Tensile testing was performed using a wire myograph in 9 bovine retinal artery specimens. Results. In-vivo results showed a significant positive correlation between rPWV (4.9±1.8 mm/s) and MAP (R2=0.58, p0.001) as expected. Ex-vivo, calculated rPWV using material stiffness and geometry measurement ranged between 4.6 and 7.0 m/s at effective distending pressures between 70 and 100 mmHg. Conclusions. Ex-vivo and in-vivo results differed by three orders of magnitude but should be the same. Ex-vivo results are in the same order as measured in-vivo in large arteries. In-vivo rPWV was lower than expected yet was responsive to changes in MAP. Further studies are required to uncover what rPWV is a measurement of, if not arterial stiffness.

AB - Background. Pulse wave velocity (PWV) in large arteries is a pressure-dependent marker of arterial stiffness. The retinal vasculature provides unique access to the microcirculation. There is inconsistency between reported values of retinal PWV (rPWV). The pressure dependency of rPWV was measured in-vivo and calculated ex-vivo using retinal artery material properties to investigate the inconsistencies. Methods. High-speed fundus videos (125 fps) from three Sprague Dawley rats were recorded simultaneously with electrocardiogram and blood pressure. rPWV was measured using the cardiac component of retinal artery diameter waveforms at two retinal sites across a physiological range (70-130 mmHg) of mean arterial pressure (MAP). Ex-vivo tensile testing was performed on bovine retinal arteries, rat retinal arteries being too small for myography. Diameter and wall thickness of the retinal artery adjacent to the optic disc were measured using optical coherence tomography. Tensile testing was performed using a wire myograph in 9 bovine retinal artery specimens. Results. In-vivo results showed a significant positive correlation between rPWV (4.9±1.8 mm/s) and MAP (R2=0.58, p0.001) as expected. Ex-vivo, calculated rPWV using material stiffness and geometry measurement ranged between 4.6 and 7.0 m/s at effective distending pressures between 70 and 100 mmHg. Conclusions. Ex-vivo and in-vivo results differed by three orders of magnitude but should be the same. Ex-vivo results are in the same order as measured in-vivo in large arteries. In-vivo rPWV was lower than expected yet was responsive to changes in MAP. Further studies are required to uncover what rPWV is a measurement of, if not arterial stiffness.

U2 - 10.1016/j.artres.2018.10.041

DO - 10.1016/j.artres.2018.10.041

M3 - Meeting abstract

SN - 1872-9312

VL - 24

SP - 75

JO - Artery Research

JF - Artery Research

IS - C

M1 - 4.2

T2 - Association for Research into Arterial Structure and Physiology Conference 2018

Y2 - 18 October 2018 through 20 October 2018

ER -

Discrepancy between in-vivo measure and ex-vivo calculation of pulse wave velocity in retinal arteries

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