The influence of multidirectional shear stress on plaque progression and composition changes in human coronary arteries.

Local wall shear stress (WSS) plays an important role in the onset of atherosclerotic plaque formation; however, it does not fully explain plaque progression and destabilisation. We aimed to investigate for the first time the influence of multidirectional WSS features on plaque progression and plaque composition changes in human coronary arteries. Coronary artery imaging using biplane angiography and virtual histology intravascular ultrasound (VH-IVUS) was performed in twenty patients with coronary artery disease at baseline and after six-month follow-up. Three-dimensional surfaces of the coronary arteries were generated using the coronary imaging and, together with patient-specific flow measurements, different WSS features (multidirectional and conventional time-averaged WSS [TAWSS]) were determined at baseline using computational fluid dynamics (CFD). The changes in plaque component area over the six-month period were determined from VH-IVUS. Changes in plaque composition rather than plaque size were primarily associated with the (multidirectional) WSS at baseline. Interestingly, regions simultaneously exposed to low TAWSS and low multidirectional WSS showed the greatest plaque progression (p<0.001). In this patient study, several multidirectional WSS features were found to contribute significantly to coronary plaque progression and changes in plaque composition.