Table 1.

Levels of shear stress and its effects on atherosclerosis

		Effects in:
Label	Range (Pa)18–22	Early atherosclerosis4	Advanced atherosclerosis4	Stented segments23,24
Oscillatory	0 ± 0.5	Athero-prone	Athero-prone	Neoathero-prone
Low	0–1
Normal/high	1–7	Athero-protective	No consensusa	Neoathero-protective
Elevated	>7	NA	Erosion	NA

In cultured endothelium, 0 ± 0.5 Pa is often used to mimic athero-prone shear stress, whereas 1.2–1.5 Pa is the most frequently used value to simulate normal, often termed high, arterial shear stress. Consistent with this, a low, oscillatory shear stress of 0.05 ± 0.5 Pa was measured in the disease prone region of the internal carotid artery^18,19 and in healthy human coronary arteries, time-averaged wall shear stress was found to be approximately 1.4 Pa.²⁰ In atherosclerotic human arteries, shear stress can vary with changes in geometry. It is elevated at the stenosis of plaques reaching >7 Pa in some instances.²¹ In cultured endothelium, 7.5 Pa is used to mimic elevated shear stress in vitro.²² However, it should be noted that low shear stress is associated with plaque progression in diseased human coronary arteries.²⁵ The effect of shear stress profiles on early and late atherosclerosis are reviewed in reference 4, and their effect on neoatherosclerosis in stented vessels are reviewed in references 23 and 24.

NA, not applicable.

^aSee Supplementary material online, Appendix B, Table B1.