Inhibition of plasmin generation in plasma by heparin, low molecular weight heparin, and a covalent antithrombin-heparin complex.

: The clinical limitations of unfractionated heparin (UFH) and low molecular weight heparin (LMWH) led to the development of an antithrombin-heparin covalent complex (ATH), which displays superior anticoagulant abilities compared with UFH. A recent study investigating its interaction with fibrinolysis showed that ATH inhibited free and fibrin bound plasmin and decreased plasmin generation on fibrin clots. These studies were conducted using purified components and did not elucidate the interaction of ATH with plasmin in the presence of its natural inhibitors α2-antiplasmin (α2-AP) and α2-macroglobulin (α2-M).