TF-induced venous thromboembolism model. (A) Anesthetized mice were injected intravenously with recombinant TF (1/8 dilution of Innovin in 0.9% NaCl; 2 μL/g body weight) via the inferior vena cava. The time to the onset of respiratory arrest that lasted at least 2 minutes was recorded for WT (■; n = 8) and Pros^+/− (△; n = 8) mice. Experiments were terminated at 20 minutes. Pros^+/− mice showed higher mortality than WT mice (P = .02), and 87.5% WT mice and 25% Pros^+/− mice survived the TF challenge. (B) In the low-TF challenge and 2 minutes after onset of respiratory arrest or at the completion of the 20-minute observation period, lungs were excised and stained with H&E. Pros^+/− mice that died within the 20-minute observation period had an increased number of thrombi (arrows, right panel), compared with WT mice that survived the TF challenge (left panel).