Conventional heparin and semisynthetic heparin analogue (SSHA) alteration of blood coagulation after embolic occlusion of human renal circulation

Blood coagulation and fibrinolytic variables were measured in a peripheral vein in a study of 21 consecutive patients before and after angio-embolization of renal carcinoma. The first ten patients received conventional heparin, 5000 IU twice daily, and the following eleven a semi-synthetic heparin analogue (SSHA), 50 mg twice daily, for 5 days. The first injection was given 2 hours before embolization and the last injection at least 12 hours before the last blood sampling. Both groups showed increased levels of FPA on day 5-7, indicating that the anticoagulant influence had ceased. F VII levels decreased only in the SSHA group from embolization to day 3, but were increased in both groups on day 5-7. Levels of thrombin-antithrombin complexes (TAT) were significantly increased in the heparin group 2 hours after embolization, indicating that thrombin activity had been formed. The corresponding TAT level in the SSHA group was not significantly increased. The differences could possibly indicate a different mechanism of action on blood coagulation of SSHA as compared with heparin, with involvement of extrinsic pathway and maybe by-passing antithrombin III inhibition.