Effect of RBCs and the RBC-free layer on NO distribution at the lumen–wall interface (clum–wal). (a) Effect of RBCs on clum–wal for different NO reaction rates (kRBC=0 s−1 indicates the dashed line; kRBC = 2.3 s−1, dotted line; kRBC = 23 s−1, solid line; kRBC = 230 s−1, dash-dotted line); (b) distributions of clum–wal for the three case simulations. The comparison between case 1 (dotted line) and case 2 (dashed line) shows that the RBC-free layer with a much lower NO reaction rate could enhance clum–wal, and the comparison between case 2 and case 3 (solid line) illustrates that endothelial glycocalyx could further increase clum–wal in the high-WSS region of the stenosis. In this set of simulations, Re = 270, the NO production rate is RNO–hyp and blood is assumed to be a Newtonian fluid.