Effect of fVII, HK, fXII, and fXI ASO treatment on the time to catheter occlusion. Rabbits (n = 7-12 per group) were given a 4-week course of control ASO or fVII, HK, fXII, or fXI ASO prior to insertion of a catheter into their jugular veins and treatment was continued. Every day for 35 days, 0.5 mL of blood was withdrawn from the catheter into a syringe and slowly reinjected. The catheter was then flushed 2 mL of saline. Catheter occlusion occurred when blood could no longer be withdrawn, saline could no longer be injected, and the pressure measured with a transducer exceeded 100 mm Hg. The bars represent the mean of at least 7 separate experiments, whereas the lines above the bars reflect the SD. *P < .001 compared with the control.