Monreal L, Villatoro A J, Monreal M, Espada Y, Anglés A M, Ruiz-Gopegui R
Department of Internal Medicine, College of Veterinary Medicine, Autonomous University of Barcelona, Spain.
Am J Vet Res. 1995 Oct;56(10):1281-5.
Thirty healthy male horses were allotted to 3 groups and treated blindly during 4 days. Group-1 horses received unfractioned calcium heparin (100 IU/kg of body weight, SC, q 12 h). Group-2 horses received a single dose of a low-molecular-weight heparin (50 anti-Xa IU/kg, SC) every morning, and a similar volume of saline solution every evening. Group-3 horses received the vehicle (saline solution), SC, every 12 hours. Citrated and EDTA-anticoagulated blood samples were collected before starting the medication (T-0) and once daily 3 hours after each morning injection (T-3, T-27, T-51, and T-75). The PCV, hemoglobin concentration, RBC and platelet counts, and clotting times (activated partial thromboplastin time and thrombin time) were determined, and a microscopic examination to detect hemagglutination was performed. Plasma concentration of heparin was measured by use of the antifactor Xa, activity assay. Bleeding time was determined on the first and fourth days, using a double-template method. The horses given unfractioned heparin had marked agglutination of erythrocytes after the first injection that became more pronounced as treatment progressed. Also, significant decrease in PCV, hemoglobin concentration, and RBC count was observed during treatment. Platelet count was significantly decreased after the first day, and clotting times were significantly prolonged. In contrast to the horses given unfractioned heparin, those given low-molecular-weight heparin did not have any agglutination of erythrocytes during the 4 days of treatment, and there were no significant changes in PCV, hemoglobin concentration, or RBC and platelet counts. Activated partial thromboplastin time increased slightly in the horses given low-molecular weight heparin, although the values remained within reference range. Both groups of horses achieved adequate concentrations of heparin in plasma for prophylactic purposes, but those given low-molecular-weight heparin achieved those values after the first injection. Bleeding times were not significantly different between heparin-treated horses and horses given saline solution during treatment. We conclude that low-molecular-weight heparin may be used more safely and conveniently in horses, because it does not affect equine erythrocytes, platelets, or clotting and bleeding times.
30匹健康雄性马被分为3组，并在4天内进行盲法治疗。第1组马接受未分级肝素钙（100 IU/kg体重，皮下注射，每12小时一次）。第2组马每天早上接受单剂量低分子肝素（50抗Xa IU/kg，皮下注射），每天晚上接受相同体积的生理盐水。第3组马每12小时接受一次赋形剂（生理盐水），皮下注射。在开始用药前（T-0）以及每天早上注射后3小时（T-3、T-27、T-51和T-75）采集枸橼酸盐和乙二胺四乙酸抗凝的血样。测定血细胞比容、血红蛋白浓度、红细胞和血小板计数以及凝血时间（活化部分凝血活酶时间和凝血酶时间），并进行显微镜检查以检测血凝。通过抗Xa活性测定法测量肝素的血浆浓度。在第1天和第4天使用双模板法测定出血时间。接受未分级肝素的马在首次注射后出现明显的红细胞凝集，随着治疗进展变得更加明显。此外，在治疗期间观察到血细胞比容、血红蛋白浓度和红细胞计数显著下降。血小板计数在第1天后显著下降，凝血时间显著延长。与接受未分级肝素的马相比，接受低分子肝素的马在治疗的4天内没有任何红细胞凝集，血细胞比容、血红蛋白浓度或红细胞和血小板计数也没有显著变化。接受低分子肝素的马的活化部分凝血活酶时间略有增加，尽管这些值仍在参考范围内。两组马的血浆中肝素浓度均达到预防目的的适当浓度，但接受低分子肝素的马在首次注射后即达到这些值。治疗期间，肝素治疗的马和接受生理盐水的马的出血时间没有显著差异。我们得出结论，低分子肝素在马中使用可能更安全、方便，因为它不影响马的红细胞、血小板或凝血及出血时间。
