PMN adhesion to fibrin formed from plasma at different shear stresses. Heparinized PPP was perfused over cover slips coated with a tissue factor–rich matrix of HUVECs at different shear stresses ranging from 0 mPa (static) to 80 mPa (20 minutes at 37°C). Subsequently, the surfaces were rinsed and used for a PMN perfusion at 200 mPa. After 5 minutes of perfusion, the total number of surface-interacting PMNs per mm2 was measured. The mean ± SE of four experiments is shown. Statistically significant shear-dependency was determined by repeated-measures ANOVA (P < .05).