TY - JOUR
T1 - Contribution of blood viscosity in the assessment of flow-mediated dilation and arterial stiffness
AU - Parkhurst, Kristin L.
AU - Lin, Hsin Fu
AU - Devan, Allison E.
AU - Barnes, Jill N.
AU - Tarumi, Takashi
AU - Tanaka, Hirofumi
PY - 2012/8
Y1 - 2012/8
N2 - Flow-mediated dilation (FMD) is a non-invasive index of endothelial function. In an attempt to standardize FMD for shear stimulus, shear rate (velocity/diameter), rather than shear stress (viscosity*velocity/ diameter), is commonly used as a surrogate measure, although it is limited by individual differences in blood viscosity. The purpose of this study was to determine the contribution of whole blood viscosity to FMD and other key measures of vascular function. Blood viscosity, FMD, carotid artery compliance, and carotid-femoral pulse wave velocity (cfPWV) were measured in 98 apparently healthy adults varying widely in age (18-63 years). Whole blood viscosity was not significantly correlated with FMD, cfPWV, or carotid artery compliance. Shear rate was a stronger correlate with FMD than shear stress that takes blood viscosity into account (r = 0.43 vs 0.28). No significant differences were observed between whole blood viscosity and traditional risk factors for cardiovascular disease. Age was positively correlated with cfPWV (r = 0.65, p < 0.001) and negatively correlated with FMD (r = -0.24, p < 0.05) and carotid artery compliance (r = -0.45, p < 0.01). Controlling for viscosity did not reduce the strength of these relations. These results indicate that whole blood viscosity does not significantly impact measures of vascular function and suggests that the common practice to use shear rate, rather than shear stress, in the adjustment of FMD is valid.
AB - Flow-mediated dilation (FMD) is a non-invasive index of endothelial function. In an attempt to standardize FMD for shear stimulus, shear rate (velocity/diameter), rather than shear stress (viscosity*velocity/ diameter), is commonly used as a surrogate measure, although it is limited by individual differences in blood viscosity. The purpose of this study was to determine the contribution of whole blood viscosity to FMD and other key measures of vascular function. Blood viscosity, FMD, carotid artery compliance, and carotid-femoral pulse wave velocity (cfPWV) were measured in 98 apparently healthy adults varying widely in age (18-63 years). Whole blood viscosity was not significantly correlated with FMD, cfPWV, or carotid artery compliance. Shear rate was a stronger correlate with FMD than shear stress that takes blood viscosity into account (r = 0.43 vs 0.28). No significant differences were observed between whole blood viscosity and traditional risk factors for cardiovascular disease. Age was positively correlated with cfPWV (r = 0.65, p < 0.001) and negatively correlated with FMD (r = -0.24, p < 0.05) and carotid artery compliance (r = -0.45, p < 0.01). Controlling for viscosity did not reduce the strength of these relations. These results indicate that whole blood viscosity does not significantly impact measures of vascular function and suggests that the common practice to use shear rate, rather than shear stress, in the adjustment of FMD is valid.
KW - carotid artery compliance
KW - pulse wave velocity
KW - shear rate
KW - shear stress
UR - http://www.scopus.com/inward/record.url?scp=84864542743&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84864542743&partnerID=8YFLogxK
U2 - 10.1177/1358863X12450095
DO - 10.1177/1358863X12450095
M3 - Article
C2 - 22848085
AN - SCOPUS:84864542743
SN - 1358-863X
VL - 17
SP - 231
EP - 234
JO - Vascular Medicine (United Kingdom)
JF - Vascular Medicine (United Kingdom)
IS - 4
ER -