Effect of heparanase inactivation on venous thrombus formation in mice. (A) Venous thrombosis was induced by subtotal IVC ligation in C57BL/6J mice at the age of 12 weeks (adult) or 12 months (aged). Mice were injected with TFPI2 peptide (2 mg/g body weight) 30 minutes before and every 24 hours after surgery. (A) High-frequency ultrasound determination of thrombus size at day 2 after surgery. Individual values and the mean ± SEM per group are shown. *P < .05. (B) Representative ultrasound images. The thrombus circumference is highlighted by broken white lines. The calculated thrombus area is also shown. (C) Thrombus weights at tissue harvest on day 2. Individual values and the mean ± SEM per group are shown. ****P < .0001. (D) Representative macroscopic images of thrombosed vein segments immediately after removal.