Platelet VWF induces localized formation of occlusive thrombi. (A) Three ROIs were delimited for the microfluidic channel test section. (B) Normalized fluorescence intensity level of each ROI after an 8-minute perfusion for WT (n = 6) and Nbeal2^−/− (n = 3) and 5 minutes for Rescue (n = 3). ROI 1 showed a significantly higher intensity level with WT and Rescue, compared with ROIs 2 and 3. **P < .01; ***P < .001. There was no significant increase in ROI 1 with Nbeal2^−/− blood. (C-D) Intensity levels of each ROI during the perfusion time. The arrow denotes the time point when WT whole blood was added to Nbeal2^−/− channels. The intensity level of ROI 1 rapidly increased after 80 seconds in the WT and 20 seconds in the Rescue mice. ns, not significant.