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Beat‐to‐beat variation in pulse wave velocity during breathing maneuvers
Author(s) -
Gaddum Nicholas R.,
Schaeffter Tobias,
Bührer Martin,
Rutten Marcel,
Smith Lorna,
Chowienczyk Philip J.,
Beerbaum Philipp B. J.
Publication year - 2014
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.24890
Subject(s) - beat (acoustics) , breathing , pulse wave velocity , pulse (music) , variation (astronomy) , nuclear magnetic resonance , physics , acoustics , medicine , anesthesia , optics , blood pressure , detector , astrophysics
Purpose Thoracic pulse wave velocity (PWV) variation due to modulated trans‐mural pressure (TMP) may indicate mechanical properties of the aorta. Our aim was to measure beat‐to‐beat thoracic PWV and TMP to observe its normal variation during respiratory maneuvers. Methods We validated PWV measurements from a real‐time velocity projection MRI scan in a pulsatile phantom. A volunteer study showed inter‐scan repeatability of steady‐state PWV, and observed PWV variation when performing Mueller and Valsalva maneuvers. Synchronized to the real‐time projection velocity data, TMP was measured using a mouth piece and pressure sensor arrangement monitoring the intra‐thoracic pressure and a single arterial pressure measurement. Results In the phantom, beat‐to‐beat PWV derived from real‐time projection (5.33 ± 0.32 m s −1 ) agreed well with experimentally derived PWV using ultrasound probes (5.72 ± 0.50 m s −1 ). The within‐subject PWV variation between scans was 0.28 m s −1 . Volunteers' PWVs increased during Mueller maneuver (TMP increase of 14.67 ± 10.69 mmHg) by 32% ( P < 0.001), and during Valsalva maneuver (TMP decrease of TMP = 17.01 ± 12.91 mmHg), PWV response were inconsistent with an average increase of 14% ( P < 0.05). Conclusion Gating TMP to beat‐to‐beat PWV allows insight into how aortic stiffness varies with strain. However, quantifying nonlinear arterial stiffness requires real‐time arterial pressure measurement. Magn Reson Med 72:202–210, 2014. © 2013 Wiley Periodicals, Inc.