Abstract: The present invention generally relates to a processes for preparing low affinity, low molecular weight heparins (LA-LWM-heparins) which are endowed with pharmacological and therapeutic properties that are surprisingly advantageous. In one embodiment, the process comprises: (1) nitrous acid depolymerization of unfractionated heparin to yield low molecular weight heparin (LMWH); (2) oxidation of the resulting LMWH to open the ring structures the nonsulfated uronic acid moieties using, for example, sodium periodate; and (3) reduction of the oxidized LMWH to reduce the aldehydes (to alcohols) formed during the depolymerization and oxidation steps using, for example, sodium borohydride. The resulting LA-LMW-heparins are capable of inactivating thrombin bound to fibrin within a thrombus or clot, whereby the ability of clot-bound thrombin to catalytically promote further clot accretion is substantially diminished or eliminated.