The relationship between coronary lesion characteristics and pathologic shear in human coronary arteries

Background: Pathological shear stress is associated with distinct pathogenic biological pathways relevant to coronary thrombosis and atherogenesis. Although the individual effects of lesion characteristics including stenosis severity, eccentricity and lesion length on coronary haemodynamics is known, their relative importance remains poorly understood. Methods: Computational fluid dynamics (CFD) was implemented for haemodynamic analysis of 104 coronary arteries. For each coronary artery, maximum shear stress at the site of maximal stenosis, average shear stress over the sites of maximal stenosis segment, average shear stress in the proximal segments and average shear stress in the distal segments were determined. In addition, the area of low wall shear stress (ALWSS) sites in post-stenotic regions were quantified as a proportion of the vessel segment. Results: With increasing stenosis severity, eccentricity and lesion length, maximal and average shear stress over the sites of maximal stenosis and ALWSS increased whereas average shear stress in the proximal segments decreased. Two-way ANCOVA analysis revealed that stenosis severity and lesion length were both independent predictors of maximum shear at the site of maximal stenosis [F (1, 104) = 10.94, P = 0.001 for diameter stenosis and F (1, 104) = 6.21, P = 0.014 for lesion length] and ALWSS [F (1, 104) = 66.10, P = 0.001 for diameter stenosis and F (1, 104) = 4.23, P = 0.047 for lesion length]. Conclusion: Our findings demonstrate that although all lesion characteristics correlate with abnormal shear stress, only stenosis severity and lesion length are independent predictors of pathogenic physiological processes.