<International Circulation>: Regarding fondaparinux， it has been shown that after PCI catheter thrombosis is more common with fondaparinux than with heparin.  Could you tell us what is going on mechanistically here?
   《国际循环》：关于fondaparinux，已经有研究表示fondaparinux相关PCI导管内血栓形成比肝素更常见，您能跟我们谈一下其中隐含的机制吗？

    Prof. Weitz:  Actually it is during the procedure that thrombosis is more common.  The reason for this is that the catheter is prothrombotic and activate clotting through the contact pathway， factor XII， and initiate clotting that way.  Because heparin inhibits all of the upstream enzymes there is more inhibition and less thrombogeneration.  The problem with fondaparinux is that， although it inhibits factor Xa， it doesn’t inhibit the other upstream coagulation factors.  It is not as good at preventing catheter-induced thrombosis.  
    Weitz教授:实际上来说，在此手术过程中血栓形成更常见。原因是导管是血栓形成的一个始动因子，而且通过接触途径，凝血因子XII以及 来启动凝血过程来活化凝血途径。问题是尽管fondaparinux抑制了Xa，它并不能抑制其它的上游凝血因子。阻止导管所致的血栓形成并不理想。

    <International Circulation>: In general， you’ve said that fondaparinux is better than heparin.  Is this still the case?
   《国际循环》：一般来说，您已经说fondaparinux优于肝素，情况真的如此吗？
    Prof. Weitz:  Fondaparinux is similar to heparin but not necessarily better.  It has efficacy and safety that is similar to low molecular weight heparin or fractionated heparin.  In this one setting of catheters， even an upper extremity in dwelling or central venous catheter， then fondaparinux would not be the treatment of choice. 

    Weitz教授:Fondaparinux与肝素疗效相似，但是不一定比肝素好。它有与低分子肝素和分馏肝素相似的疗效和安全性，在导管的环境下，甚至在外周或中央静脉导管，fondaparinux不会是治疗的选择。