High shear stress induces a strain increase in human coronary plaques over a 6-month period

Aims: Atherosclerotic plaques develop in low shear stress regions. In the more advanced phase of the disease, plaques are exposed to altered shear stress levels, which could influence plaque composition. We investigated changes in plaque composition in human coronary arteries over a 6-month period and how these changes are related to shear stress. Methods and results: We took images of eight coronary arteries to obtain the 3D shape of the arteries. Lumen data were combined with computational fluid dynamics to obtain shear stress. Palpography was applied to measure strain at baseline and at 6-month follow-up. The change in strain from baseline to follow- up served as a marker for the change in plaque composition. We identified 17 plaques, and each plaque was divided into four regions: the upstream, throat, shoulder and downstream region. Shear stress and strain in the downstream region was significantly lower than in the other regions. There was no significant change in strain for the four different plaque regions. However, we observed that those plaque regions exposed to high shear stress showed a significant increase in strain. Conclusions: Plaque regions exposed to high shear stress showed an increase in strain over time. This indicates that shear stress may modulate plaque composition in human coronary arteries.