TOPICAL APPLICATION OF LOW-MOLECULAR-WEIGHT HEPARIN IN A RABBIT TRAUMATIC ANASTOMOSIS MODEL

Low molecular weight heparins (LMWHs) are antithrombotic drugs compose d of lower molecular weight components of heparin with an apparent mol ecular weight in the range of 4.0-8.0 KDA. These agents have been used clinically for several years. They have different mechanisms of actio n compared to heparin, a longer half-life and much higher bioavailabil ity. Anticoagulant drugs such as heparin have been used topically in o ur previous studies to avoid bleeding complications observed with syst emic administration. In this study, low molecular weight heparin (Cert oparin, Sandoz) was topically administered in a rabbit ear arterial cr ush-avulsion thrombosis model and compared with heparin. The animals w ere divided into three groups: LMWH, heparin and saline control groups . In the LMWH group, the patency rate was 71% (10 of 14) at both 1 and 7 days. The patency rate in the heparin group was 95% (19 of 20) at 2 4 hrs and 80% (16 of 20) at 7 days. In the saline control group, the v essel patency rate was 17% at 24 hrs and 13% at 7 days. Clotting times such as ACT, PT and APTT performed on samples drawn one hour after dr ug administration were within the normal ranges for both the control a nd the treatment groups. The results suggest that topical administrati on of LMWH prevents the occurrence of thrombosis at the traumatic anas tomosis site to a similar degree as heparin. (C) 1997 Elsevier Science Ltd.