Low endothelial shear stress is associated with increased coronary atherosclerotic plaque activity in patients that presented with acute coronary syndrome.

Background: Both coronary atherosclerotic plaque activity and low endothelial shear stress (ESS) are predictive of adverse cardiovascular events. We aimed to investigate their association and relationship with high-risk plaque features.

Methods: Coronary computed tomography angiography (CCTA) based flow simulations were used to compute ESS in patients presenting with acute coronary syndrome proceeding percutaneous coronary intervention. Associations between ESS, CCTA plaque features and coronary plaque activity, measured by ¹⁸F-sodium fluoride (¹⁸F-NaF) positron emission tomography (PET), were investigated at the coronary segment and vessel level.

Results: ESS and coronary plaque activity were both analyzed in 330 coronary segments and 123 vessels. The area of low ESS (<0.4 ​Pa), termed low shear area (LSA), was larger in ¹⁸F-NaF positive regions increasing from median 11.7 ​mm² (IQR: 4.6-27.4) to 29.0 ​mm² (IQR: 14.1-55.2) at the segment level (P ​< ​0.0001) and from median 27.3 ​mm² (IQR: 8.6-65.3) to 57.8 ​mm² (26.6-108.2) at the vessel level (P ​= ​0.0049). The maximum tissue-to-background ratio of ¹⁸F-NaF activity positively correlated with LSA at the segment level (r_s ​= ​0.27; P ​< ​0.0001) and at the vessel level (r_s ​= ​0.38; P ​< ​0.0001). LSA was associated with spotty calcification at both the segment (P <0.0001) and vessel level (P ​= ​0.0042) and positive remodeling at the vessel level (P ​= ​0.025).

Conclusions: In patients with acute coronary syndrome, LSA is associated with increased coronary atherosclerotic plaque activity, as measured by ¹⁸F-NaF PET.