Effect of heparin, low molecular weight (LMW) heparin, and a heparin analogue on experimental venous thrombosis in the rabbit.

An experimental model based on a combination of endothelial injury and flow reduction, was used to induce jugular vein thrombosis in the rabbit. The influence of conventional heparin, a low molecular weight fragment (LMW heparin; M.W. 4 000-5 000) and a heparin analogue (sodium pentosan polysulfate) was compared. The drugs were administered intravenously during the induction of thrombosis. The control animals received Ringer's lactate. All treatments significantly reduced the frequency of thrombosis. In addition, LMW heparin caused a significant reduction of thrombus weight. Moreover, it was shown that local treatment with conventional heparin and LMW heparin after endothelial damage both reduced the frequency of thrombosis.