The effect of sTF-annV or factor VIIa on the aPTT of heparin-treated plasma. (A) aPTT assays of plasma containing heparin sodium (1 unit/mL) were measured in the presence of various concentrations of factor VIIa (•) or sTF-annV (▪). (B) The aPTT of plasma containing enoxaparin sodium (1 unit/mL) was measured in the presence of various concentrations of factor VIIa (•) or sTF-annV (▪). The dotted lines show the mean clotting time for the aPTT assay in the absence of heparin or enoxaparin. Shown are means ± SEM. (Most error bars are too small to be seen.)