Monreal M, Silveira P, Monreal L, Monasterio J, Angles A M, Lafoz E, Lorente L
Unit of Experimental Thrombosis, Facultad de Veterinaria, Universidad Autonoma de Barcelona, Spain.
Haemostasis. 1991;21(2):91-7. doi: 10.1159/000216209.
In a randomized, blind study, both the antithrombotic efficacy (reduction of thrombus weight) and potency (anti-Xa activity) of several commercially available low-molecular-weight heparins (LMWHs) were compared with those of unfractioned heparin (UFH) and placebo. Three different thrombogenic challenges were used: venous thrombosis was induced by direct endothelial damage in 60 New Zealand rabbits (group I), intracarotid injection of bovine thrombin in an additional series of 60 rabbits (group II), or after inferior-vena-cava ligature in 60 Wistar rats (group III). The drugs were administered subcutaneously 2 h before surgery in a blind fashion. The doses recommended for clinical practice were used (adjusted by body weight), except in group II animals, in whom doses were doubled. No differences were found between UFH and most LMWHs in terms of reduction of thrombus weight in group I animals. But UFH showed a weaker antithrombotic efficacy in the other two models. Similarly, one of the LMWHs used (Clexane) proved to be not as effective as the remainder. However, only clinical studies will provide enough information to verify these differences. Additionally, our findings confirm that the antithrombotic efficacy of a given drug differs according to the stimulus used to induce venous thrombosis.
在一项随机双盲研究中，将几种市售低分子肝素（LMWH）的抗血栓形成功效（血栓重量减轻）和效能（抗Xa活性）与普通肝素（UFH）和安慰剂进行了比较。采用了三种不同的致血栓形成刺激：在60只新西兰兔中通过直接内皮损伤诱导静脉血栓形成（I组），在另外60只兔中进行颈内动脉注射牛凝血酶（II组），或在60只Wistar大鼠中进行下腔静脉结扎后诱导静脉血栓形成（III组）。在手术前2小时以盲法皮下给药。除II组动物剂量加倍外，使用了临床实践推荐的剂量（按体重调整）。在I组动物中，UFH与大多数LMWH在血栓重量减轻方面未发现差异。但在其他两种模型中，UFH显示出较弱的抗血栓形成功效。同样，所使用的一种LMWH（克赛）被证明不如其余的有效。然而，只有临床研究才能提供足够的信息来证实这些差异。此外，我们的研究结果证实，给定药物的抗血栓形成功效因诱导静脉血栓形成的刺激因素而异。
