High Spatial Endothelial Shear Stress Gradient Independently Predicts Site of Acute Coronary Plaque Rupture and Erosion.

AIMS To investigate local haemodynamics in the setting of acute coronary plaque rupture and erosion. METHODS AND RESULTS Intracoronary optical coherence tomography performed in 37 patients with acute coronary syndromes caused by plaque rupture (n = 19) or plaque erosion (n = 18) was used for 3D reconstruction and computational fluid dynamic simulation. Endothelial shear stress (ESS), spatial ESS gradient (ESSG), and oscillatory shear index (OSI) were compared between plaque rupture and erosion through mixed-effects logistic regression. Lipid, calcium, macrophages, layered plaque, and cholesterol crystals were also analysed. By multivariable analysis, only high ESSG (odds ratio [OR] 5.29, 95% confidence interval [CI] 2.57-10.89, p < 0.001), lipid (OR 12.98, 95% CI 6.57-25.67 p < 0.001), and layered plaque (OR 3.17, 95% CI 1.82-5.50, p < 0.001) were independently associated with plaque rupture. High ESSG (OR 13.28, 95% CI 6.88-25.64, p < 0.001), ESS (OR 2.70, 95% CI 1.34-5.42, p = 0.005) and OSI (OR 2.18, 95% CI 1.33-3.54, p = 0.002) independently associated with plaque erosion. ESSG was higher at rupture sites than erosion sites (median (interquartile range): 5.78 (2.47, 21.15) versus 2.62 (1.44, 6.18) Pa/mm, p = 0.009), OSI was higher at erosion sites than rupture sites (1.04x10-2 (2.3x10-3, 4.74x10-2) versus 1.29x10-3 (9.39x10-5, 3.0x10-2), p < 0.001), but ESS was similar (p = 0.29). CONCLUSIONS High ESSG is independently associated with plaque rupture while high ESSG, ESS, and OSI associate with plaque erosion. While ESSG is higher at rupture sites than erosion sites, OSI is higher at erosion sites and ESS was similar. These results suggest that ESSG and OSI may play critical roles in acute plaque rupture and erosion, respectively. TRANSLATIONAL PERSPECTIVE Plaque rupture and erosion are distinct pathological and clinical entities with possibly different optimal treatments. This study demonstrates that high endothelial shear stress gradient is independently associated with site of both rupture and erosion, and is significantly higher in rupture. High oscillatory shear index is independently associated with the site of erosion only, and is higher in erosion than rupture. Larger studies are necessary to determine whether these indices may detect and distinguish plaque rupture and erosion in a clinical setting or to assess overall risk for acute coronary syndromes.