Abstract

Abdominal aortic aneurysm (AAA) is a disease of the aortic wall, which can progress to catastrophic rupture. Assessment of mechanical characteristics of AAA, such as aortic distensibility, may provide important insights to help identify at-risk patients and understand disease progression. While the majority of studies on this topic have focused on retrospective patient data, recent studies have used mouse models of AAA to prospectively evaluate the evolution of aortic mechanics. Quantification of aortic distensibility requires accurate measurement of arterial blood pressure, particularly pulse pressure, which is challenging to perform accurately in murine models. We hypothesized that volume/pressure tail-cuff measurements of arterial pulse pressure in anesthetized mice would have sufficient accuracy to enable calculations of aortic distensibility with minimal error. Telemetry devices and osmotic mini-pumps filled with saline or angiotensin-II were surgically implanted in male apolipoprotein-E deficient (ApoE-/-) mice. Blood pressure in the aortic arch was measured continuously via telemetry. In addition, simultaneous blood pressure measurements with a volume/pressure tail-cuff system were performed under anesthesia at specific intervals to assess agreement between techniques. Compared to controls, mice infused with angiotensin-II had an overall statistically significant increase in systolic pressure, with no overall difference in pulse pressure; however, pulse pressure did increase significantly with time. Systolic measurements agreed well between telemetry and tail-cuff (coefficient of variation = 10%), but agreement of pulse pressure was weak (20%). In fact, group-averaged pulse pressure from telemetry was a better predictor of a subject's pulse pressure on a given day than a simultaneous tail-cuff measurement. Furthermore, these approximations introduced acceptable errors (15.1 ± 12.8%) into the calculation of aortic distensibility. Contrary to our hypothesis, we conclude that tail-cuff measures of arterial pulse pressure have limited accuracy. Future studies of aneurysm mechanics using the ApoE-/-/angiotensin-II model would be better in assuming pulse pressure profiles consistent with our telemetry findings instead of attempting to measure pulse pressure in individual mice.

Document Type

Article

Publication Date

6-18-2015

Notes/Citation Information

Published in PLOS One, v. 10, no. 6, article e0130723, p. 1-14.

© 2015 Haggerty et al.

This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Digital Object Identifier (DOI)

http://dx.doi.org/10.1371/journal.pone.0130723

Funding Information

This study was supported by a National Research Service Award (F32 HL123215) from the National Institutes of Health (nih.gov) (CMH), and a pilot award from a National Institutes of Health Clinical & Translational Science Award (UL1 TR000117) (BKF, CMH). This work is the sole responsibility of the authors; the funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Additional Files
DataSupplement1.mat (12 kB)
S1 File. Mean telemetry data for all subjects.
DataSupplement1_ang_1.mat (1411 kB)
S2 File. All telemetry data, AngII subject 1.
DataSupplement1_ang_2.mat (3972 kB)
S3 File. All telemetry data, AngII subject 2.
DataSupplement1_ang_3.mat (3986 kB)
S4 File. All telemetry data, AngII subject 3.
DataSupplement1_ang_4.mat (3951 kB)
S5 File. All telemetry data, AngII subject 4.
DataSupplement1_ang_5.mat (3994 kB)
S6 File. All telemetry data, AngII subject 5.
DataSupplement1_ang_6.mat (3951 kB)
S7 File. All telemetry data, AngII subject 6.
DataSupplement1_control_1.mat (3895 kB)
S8 File. All telemetry data, Control subject 1.
DataSupplement1_control_2.mat (3884 kB)
S9 File. All telemetry data, Control subject 2.
DataSupplement1_control_3.mat (3884 kB)
S10 File. All telemetry data, Control subject 3.
DataSupplement1_control_4.mat (1418 kB)
S11 File. All telemetry data, Control subject 4.
DataSupplement1_control_5.mat (3864 kB)
S12 File. All telemetry data, Control subject 5.
DataSupplement2.mat (23 kB)
S13 File. Telemetry and tail-cuff comparison data.
DataSupplement3.mat (1 kB)
S14 File. Conscious vs. Anesthetized telemetry comparison data.
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