Wall shear rate in supra-aortic vessels: a factor for different atherosclerotic pattern?

Atherosclerotic lesions of the upper extremity arise three to five times more often at the origin of the left subclavian artery than on the right side. The aim of this study was to investigate, whether the hemodynamic forces (peak wall shear rate) in the large supra-aortic branches measured by MRI differ in healthy subjects.

Peak wall shear rate (WSR) and blood flow was assessed in the left carotid, left subclavian and innominate artery in ten healthy volunteers (5 females, mean age of 35.2 +/- 9 years) using high resolution (pixel size 0.6 mm 2) magnetic resonance imaging (MRI) flow velocity measurements.

There is no difference between the maximum WSR of the three large supra-aortic vessels. Only within the proximal (327 +/- 132s-1) and distal wall (458 +/- 154s-1) of the innominate artery a significant difference (p = 0.011) of the WSR was found.

The results from this study indicate that WSR is not different in the supra-aortic vessels. Therefore the atherosclerotic pattern in the subclavian and innominate arteries may not be explained by differences in these hemodynamic forces.