[Mode of action and control of "low dose heparin" (author's transl)].

Investigating the mechanism of action of "low dose heparin" it could be shown that this type of anticoagulation--in addition to other mechanisms--inhibits the contact phase of the intrinsic coagulation system. Thus "low dose heparin" would be directed against the hypercoagulability that arises via increased contact activation of the intrinsic system by inflammatory or degenerative processes of the vessel walls. Further the biological significance of "low dose heparin" was demonstrated by a prolongation of the half life of 125J-fibrinogen. In general a laboratory control of "low dose heparin"-prophylaxis is not required. In patients with an increased "tolerance" for heparin, however, the determination of the thrombin time with a thrombin-solution of low concentration (1 N.I.H.-unit/ml) might be useful to indicate whether the dosage of heparin has to be increased or not.