Inferior vena cava thrombi in male AA vs AS mice. (A) Thrombus weight after 24 hours of IVC stasis in AA (n = 7) compared with AS mice (n = 8). (B) Demonstration of severe hypoxia (<10 mm Hg) in the nidus of an IVC clot from a control (AA) mouse, illustrated by the presence of fluorescent cells (white arrow) in the central zone of the thrombus. Individual cells are primarily leucocytes. Black arrows point to the IVC clot surface that abutted the IVC lumen in vivo. (C) Hematoxylin and eosin (H&E) staining showing sickled red cells in the innermost zone of an IVC thrombus from an AS mouse. ∗∗P < .01.