Heparin affinity of factor VIIa: Implications on the physiological inhibition by antithrombin and clearance of recombinant factor VIIa

These results indicate that FVIIa binds to exposed glycosaminglycans of the endothelium through an exosite II, structurally similar to that reported for thrombin and suggested for FIXa. This binding may favor its inhibition by antithrombin in the absence of TF, contributing to the physiological control of this protease. This process may also play an important role in the clearance of recombinant FVIIa administered to patients.