Abstract
The level of hematocrit (Hct) is known to affect mean arterial pressure (MAP) by influencing blood viscosity. In the healthy population, an increase in Hct (and corresponding increase in viscosity) tends to raise MAP. However, data from a clinical study of type 2 diabetic patients indicate that this relationship is not universal. Instead, individuals in the lower levels of Hct range display a decrease in MAP for a given rise in Hct. After reaching a minimum, this trend is reversed, so that further increases in Hct lead to increases in MAP. We hypothesize that this anomalous behavior occurs due to changes in the circulatory autoregulation mechanism. To substantiate this hypothesis, we develop a physically based mathematical model that incorporates autoregulation mechanisms. Our model replicates the anomalous U-shaped relationship between MAP and Hct found in diabetic patients in the same range of Hct variability.
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Abbreviations
- P :
-
Pressure
- P z :
-
Pressure gradient
- T :
-
Tension
- r :
-
Vessel radius
- A :
-
Activation
- C j :
-
Constant associated with the subscript j
- r 0 :
-
Reference vessel radius
- S t :
-
Stimulus
- σ :
-
Shear stress
- Q :
-
Flow rate
- μ:
-
Effective blood viscosity
- MAP:
-
Mean arterial pressure
- Hct:
-
Hematocrit
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Acknowledgments
This work was supported by USPHS NIH grant HLBI R01-62354.
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Open Access This is an open access article distributed under the terms of the Creative Commons Attribution Noncommercial License (https://creativecommons.org/licenses/by-nc/2.0), which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
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Branigan, T., Bolster, D., Vázquez, B.Y.S. et al. Mean arterial pressure nonlinearity in an elastic circulatory system subjected to different hematocrits. Biomech Model Mechanobiol 10, 591–598 (2011). https://doi.org/10.1007/s10237-010-0258-y
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DOI: https://doi.org/10.1007/s10237-010-0258-y