Low molecular weight heparin salt with triethanolamine useful as a therapeutic-antithrombotic agent for local delivery, having at least 60% of its total mass a molecular weight of less than 8000 Da and an average molecular weight from 4000 to 6000 Da, said salt also having a content of organic sulfur from 6.1 to 7.5 weight % (theoretical 6.8%) and a triethanolamine content from 42.6 to 52.1 weight % (theoretical 47.4 weight %). The processes for preparing the heparin salt, eliminating hygroscopicity of said salt, and pharmaceutical compositions for use in local antithrombotic therapy and its uses are also disclosed.