Coagulation Laboratory, Gentofte University Hospital, Hellerup, Denmark.
Thromb J. 2009 Nov 10;7:14. doi: 10.1186/1477-9560-7-14.
Low molecular weight heparin (LMWH) is in vast usage for treatment of thromboembolic diseases such as deep venous thrombosis and acute coronary syndromes. There are certain clinical situations where a quick point of care testing of the effect of LMWH would be useful. At this point there are no point of care devices available in the market for monitoring the effect of LMWH. Thrombelastography (TEG) evaluates the viscoelastic properties of blood during coagulation. The clinical application of TEG in monitoring LMWH treatment is not yet well defined. The purpose of this in vivo study was to systematically evaluate the most suitable TEG parameters for evaluation of the antithrombotic effect of LMWH. We furthermore evaluated for the first time the usefulness of the composite TEG parameter the Thrombodynamic Ratio (TDR) in monitoring LMWH treatment.
Healthy male volunteers (n = 7) were injected subcutaneously with the LMWH dalteparin 120 IU/kg. TEG parameters and antifactor Xa levels were measures at baseline, 2, 4, 5 and 24 hours after the injection. Correlation between TEG parameters and antiXa were calculated. The sensitivity and specificity of the TEG parameters for plasma levels of antiXa in the therapeutic range of 0.5 - 1.0 U/ml were calculated.
All basic TEG parameters correlated significantly with antiXa levels. Among the basic parameters, the TEG reaction time R had the best correlation with antiXa levels with the most favorable combination of sensitivity and specificity for the therapeutic range of antiXa levels (r = 0.82, p < 0.0001, sensitivity 68%, specificity 100%). The composite TEG parameter TDR demonstrated the best correlation with antiXa levels, and an even more favorable combination of sensitivity and specificity compared to any of the basic parameters (r = - 0.87, p < 0.0001, sensitivity 95%, specificity 79%).
The TEG reaction time R and TDR are the most suitable TEG parameters for evaluation of the antithrombotic effect of dalteparin with a highly significant correlation with antiXa levels in healthy male volunteers. Measures for uniform clinical use of these parameters are proposed. Larger clinical trials are needed to correlate R and TDR with clinical outcomes.
低分子量肝素（LMWH）被广泛用于治疗深静脉血栓形成和急性冠脉综合征等血栓栓塞性疾病。在某些临床情况下，快速检测 LMWH 的效果将非常有用。目前，市场上没有用于监测 LMWH 效果的即时检测设备。血栓弹力描记术（TEG）评估血液在凝固过程中的粘弹性特性。TEG 在监测 LMWH 治疗中的临床应用尚未得到很好的定义。本体内研究的目的是系统地评估最适合评估 LMWH 抗血栓作用的 TEG 参数。我们还首次评估了复合 TEG 参数血栓动力比（TDR）在监测 LMWH 治疗中的有用性。
健康男性志愿者（n=7）皮下注射 LMWH 达肝素 120IU/kg。在注射后 2、4、5 和 24 小时测量 TEG 参数和抗因子 Xa 水平。计算 TEG 参数与抗 Xa 的相关性。计算 TEG 参数在治疗范围内（0.5-1.0U/ml）的抗 Xa 血浆水平的敏感性和特异性。
所有基本 TEG 参数与抗 Xa 水平均呈显著相关。在基本参数中，TEG 反应时间 R 与抗 Xa 水平相关性最好，对治疗范围内抗 Xa 水平具有最佳的敏感性和特异性组合（r=0.82，p<0.0001，敏感性 68%，特异性 100%）。复合 TEG 参数 TDR 与抗 Xa 水平相关性最好，与任何基本参数相比，具有更有利的敏感性和特异性组合（r=-0.87，p<0.0001，敏感性 95%，特异性 79%）。
TEG 反应时间 R 和 TDR 是评估达肝素抗血栓作用最适合的 TEG 参数，与健康男性志愿者的抗 Xa 水平有高度显著的相关性。提出了用于统一临床应用这些参数的措施。需要进行更大的临床试验，以将 R 和 TDR 与临床结果相关联。
