Thrombus formation after laser-induced injury in cremaster arterioles of WT and VWF^−/− mice. Localized laser injury was induced to endothelial cells of arterioles with a diameter of 35 to 60 μm, and thrombus growth was immediately recorded (1-second intervals). (A) The mean thrombus surface versus time after laser-induced injury (24 thrombi in 6 WT mice and 25 thrombi in 5 VWF^−/− mice). The mean thrombus surface was analyzed every 5 seconds; data are presented as means plus or minus SEM. The photographs represent the thrombus at maximal size in a WT and a VWF^−/− mouse after laser injury. Original magnification, ×400. (B) Time required for maximal surface for each thrombus in WT and VWF^−/− mice. The mean time of each group is indicated by a horizontal line, and no significant difference was observed (P = .46). (C) Maximal surface reached at the peak for each thrombus in WT and VWF^−/− mice. The mean maximal surface of each group is indicated by a line, and no significant difference was observed (P = .31).