Quantification of Aortic Stiffness by Ultrasound Time-Harmonic Elastography: The Effect of Intravascular Pressure on Elasticity Measures in a Porcine Model
Schaafs LA, Tzschaetzsch H, Steffen IG, Braun J, Hamm B, Sack I, Elgeti T (2020)
Publication Type: Journal article
Publication year: 2020
Journal
Book Volume: 55
Pages Range: 174-180
Journal Issue: 3
DOI: 10.1097/RLI.0000000000000618
Abstract
Objectives The aim of this study was to investigate blood pressure dependency of ultrasound time-harmonic elastography (THE) for quantification of aortic stiffness. Materials and Methods Thoracoabdominal aortas were surgically removed from 9 healthy domestic pigs and prepared for elastographic experiments. All vessels were connected to a saline-filled water column with adjustable height and pressurized over a range of 0 to 110 mm Hg in 10 mm Hg increments to simulate different levels of mean arterial pressure. In addition, 3 of the 9 aortas were soaked in 4% buffered formaldehyde for 60 minutes to simulate pathologic aortic stiffening. Ultrasound THE was performed in each vessel at each pressure level. For each pressure level, shear-wave speed (SWS) as a measure of aortic wall stiffness and luminal diameter were recorded. The pressure range between 30 and 110 mm Hg was used for statistical evaluation as it reflects a physiological mean arterial pressure range. Linear regression analysis and multivariate analysis with a general linear model were performed to evaluate the influence of increasing intravascular pressure and vessel diameter on measured SWS. Results Median SWS in formalin-soaked aortas was significantly higher with 3.22 m/s (interquartile range [IQR], 0.01 m/s) versus 2.14 m/s (IQR, 0.09) at 30 mm Hg and 3.38 m/s (IQR, 0.01 m/s) versus 2.28 m/s (IQR, 0.07 m/s) at 110 mm Hg (each P = 0.01). Using linear regression analysis, an increase of aortic wall SWS of 0.017 m/s per 10 mm Hg intraluminal pressure was found in untreated aortas, whereas SWS increased by 0.020 m/s per 10 mm Hg in formalin-soaked aortas (both P = 0.001). The percentage of SWS caused by intraluminal pressure was 1.89% in formalin-soaked aortas and 2.50% in untreated aortas at 30 mm Hg and 6.61% for formalin-soaked aortas and 8.60% for untreated aortas at 110 mm Hg. Multivariate analysis showed no significant interaction of luminal diameter and measured SWS (P = 0.893). Conclusions In our model, aortic stiffness measurements by ultrasound time-harmonic elastography are influenced to a small extent by mean arterial pressure in a range of 1.89% to 8.60%. These findings emphasize the potential of ultrasound THE for measuring the intrinsic stiffness of the aortic wall in clinical routine.
Involved external institutions
Germany (DE)How to cite
APA:
Schaafs, L.-A., Tzschaetzsch, H., Steffen, I.G., Braun, J., Hamm, B., Sack, I., & Elgeti, T. (2020). Quantification of Aortic Stiffness by Ultrasound Time-Harmonic Elastography: The Effect of Intravascular Pressure on Elasticity Measures in a Porcine Model. Investigative Radiology, 55(3), 174-180. https://doi.org/10.1097/RLI.0000000000000618
MLA:
Schaafs, Lars-Arne, et al. "Quantification of Aortic Stiffness by Ultrasound Time-Harmonic Elastography: The Effect of Intravascular Pressure on Elasticity Measures in a Porcine Model." Investigative Radiology 55.3 (2020): 174-180.
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