In-vivo measurement of wall shear stress in angiographically normal human coronary arteries yielded a mean value of 0.68 Pa, which is half the value predicted from optimality principles.
Observational (n=21)
The mean in-vivo wall shear stress in normal human coronary arteries at rest is 0.68 Pa, which is lower than predicted by optimality principles and smaller than values in other major arteries.
BACKGROUND: Wall shear stress (WSS) is closely associated with arteriosclerosis. WSS values for various vessels and species are available, but fully in-vivo measurements in human coronary arteries have not yet been reported. OBJECTIVE: To measure WSS in undiseased coronary arteries of adult patients at rest. METHODS: We recorded the temporal average value (APV) of the instantaneous maximal blood velocity in the three vessel segments of angiographically normal coronary artery bifurcations in 21 patients undergoing cardiac catheterization to treat various diseases by means of a 0.036 cm Doppler wire (FloWire). In total, 36 bifurcations were examined. The 36 x 3 cross-sectional areas (CSA) were determined by means of a three-dimensional angiographic technique. The three flows, Q1 (inflow), Q2, and Q3 of each bifurcation were calculated according to Q=0.5 x APV x CSA. For each segment, WSS was calculated as WSS=32 eta Q/(pi D3) (where blood viscosity eta=3.5 mPa s and D is vessel diameter). Only the 54 WSS values obtained from the 18 flow triplets which satisfied the equation Q1/(Q2+Q3)=1 better than did the 18 other ones were retained. RESULTS: The 54 WSS values ranged from 0.33 to 1.24 Pa (mean 0.68 Pa, SEM, 0.027 Pa). They did not depend significantly on Q (r=0.07; P=0.60) and the CSA (r=0.24, P=0.08) but the second relationship approached significance. CONCLUSION: The obtained mean WSS value (0.68 Pa) is half the value predicted for coronary arteries from optimality principles. It is also smaller than many values reported for human carotid, renal, and femoral arteries.
Doriot et al. (2000) conducted an observational in Undiseased coronary arteries (n=21). In-vivo measurement of wall shear stress using Doppler wire and 3D angiography was evaluated on Wall shear stress (WSS). In-vivo measurement of wall shear stress in angiographically normal human coronary arteries yielded a mean value of 0.68 Pa, which is half the value predicted from optimality principles.