Artery Research

Volume 8, Issue 4, December 2014, Pages 161 - 161

P11.1 THE PU AND QA LOOP METHODS OVER- AND UNDERESTIMATE LOCAL CAROTID WAVE SPEED: A CONSISTENT EXPLANATION AND SOLUTION TO THE PROBLEM

Authors
P. Segers, A. Swillens, L. Taelman, J. Vierendeels
Ghent University, Ghent, Belgium
Available Online 4 November 2014.
DOI
10.1016/j.artres.2014.09.219How to use a DOI?
Open Access
This is an open access article distributed under the CC BY-NC license.

Single-point methods such as the PU- and QA-loop methods are used to estimate local pulse wave velocity (PWV-PU and PWV-QA) in arteries from a combination of pressure (P), flow (Q), velocity (U) or cross-sectional area (A) waveforms. Available data indicate that the PU-loop method tends to overestimate PWV, while the QA-loop method tends to underestimate. Wave reflection has been suggested as a factor playing a role in the agreement between different methods. In this work, we (i) demonstrate the interference of wave reflection with the PU-loop method for both solitary sinusoidal waves as well as physiological waveforms; (ii) develop an operator-independent method to correct for the presence of reflections. Fluid-structure interaction simulations in a tube and carotid artery model with known mechanical properties confirm the theory. For the carotid artery model, PWV-PU severely overestimates PWV, while PWV-QA underestimates PWV. Correction (leading to an estimate termed PWV-corr) eliminates the impact of reflections. Finally, methods are applied in vivo in a subsample of the Asklepios population. Compared to PWV-PU and PWV-QA, PWV-corr leads to significantly better correlations of carotid PWV with PWV derived from carotid distensibility based on the Bramwell-Hill equation(with r2 improving from about 0.25 to 0.91). Neither the PU-loop nor the QA-loop method provides reliable estimates of local PWV in settings where wave reflections are present - even when the PU- or QA-loops show a linear segment. They offer no alternative for the Bramwell-Hill based approach and their application should therefore be discouraged, especially for the carotid artery.

Journal
Artery Research
Volume-Issue
8 - 4
Pages
161 - 161
Publication Date
2014/11/04
ISSN (Online)
1876-4401
ISSN (Print)
1872-9312
DOI
10.1016/j.artres.2014.09.219How to use a DOI?
Open Access
This is an open access article distributed under the CC BY-NC license.

Cite this article

TY  - JOUR
AU  - P. Segers
AU  - A. Swillens
AU  - L. Taelman
AU  - J. Vierendeels
PY  - 2014
DA  - 2014/11/04
TI  - P11.1 THE PU AND QA LOOP METHODS OVER- AND UNDERESTIMATE LOCAL CAROTID WAVE SPEED: A CONSISTENT EXPLANATION AND SOLUTION TO THE PROBLEM
JO  - Artery Research
SP  - 161
EP  - 161
VL  - 8
IS  - 4
SN  - 1876-4401
UR  - https://doi.org/10.1016/j.artres.2014.09.219
DO  - 10.1016/j.artres.2014.09.219
ID  - Segers2014
ER  -