Ofosu F A
Canadian Red Cross Society, Blood Transfusion Service, Hamilton, Ont., Canada.
Haemostasis. 1990;20 Suppl 1:180-92. doi: 10.1159/000216177.
Low molecular weight (LMW) heparins achieve their anticoagulant effects by inhibiting prothrombin activation, catalyzing endogenous thrombin inhibition, and binding thrombin. The extent of which each of the three actions of LMW heparins contributes to the antithrombotic effectiveness of LMW in man has not been defined. Several studies have reported that ex vivo anti-factor Xa activities of LMW heparins correlate with efficacy and potential haemorrhagic complications. However, critical review of the data suggests that anti-factor Xa assays are basically surrogate tests for the mass of LMW heparins in patients' plasmas rather than reliable estimates of total catalytic concentrations of LMW heparins. Antithrombotic effectiveness of LMW heparins probably reflects their ability to inhibit coagulation in vivo. If the last concept proves correct, then results of tests which directly assess the extents to which LMW heparins have suppressed in vivo coagulation may provide more reliable markers for their antithrombotic effectiveness or lack thereof.
低分子量（LMW）肝素通过抑制凝血酶原激活、催化内源性凝血酶抑制以及结合凝血酶来实现其抗凝作用。LMW肝素的这三种作用各自对LMW肝素在人体内的抗血栓形成效果的贡献程度尚未明确。几项研究报告称，LMW肝素的体外抗Xa因子活性与疗效和潜在出血并发症相关。然而，对数据的严格审查表明，抗Xa因子检测基本上是患者血浆中LMW肝素质量的替代检测，而不是LMW肝素总催化浓度的可靠估计。LMW肝素的抗血栓形成效果可能反映了它们在体内抑制凝血的能力。如果最后这个概念被证明是正确的，那么直接评估LMW肝素在体内抑制凝血程度的检测结果可能会为其抗血栓形成效果或缺乏抗血栓形成效果提供更可靠的指标。
