<International Circulation>：OK， that’s for my official questions but just out of curiosity: why is it that thrombolysis treatment is limited to four-point-five hours? What is it that after four-point-five hours causes it to be ineffective?

　　《国际循环网》：好吧，以上是比较正式的问题，出于好奇心下面我还想向您请教：为什么溶栓治疗时间窗控制在4.5小时内？是什么导致4.5小时后治疗无效？

　　Kaste Markku：It looks like one again it’s an every-minute counts situation. We say that， “Time is brain”. And if you open it quite late and there are already clots in action the risk that it does to hemorrhagic stroke is high.  So you increase the death rate. We have to also keep in mind that it is not only the brain tissue that is ischemic but also the tissue in the arterial wall. So all sorts of arterial walls are suffering and if time goes on， it’s open then it’s easier that it will rupture. And that’s the reason why t-PA cannot be given that much later because the risk of intracerebral hemorrhage goes up so much that the proportion of risk to benefit becomes no longer acceptable.

　　Kaste Markku：溶栓治疗是争分夺秒，抢占先机的治疗过程。可以说“时间就是大脑”。如果治疗过晚的话，会有血栓形成，增加出血性卒中风险，同时也增加死亡几率。我们必须谨记：不仅脑组织会缺血，动脉壁组织也会。所有动脉血管壁都易受损，如果短时间内不进行溶栓治疗，随时间推移，血管壁将有穿孔可能，造成严重出血事件，是t-PA不能太晚使用的原因，太晚使用t-PA导致的严重颅内出血风险增加远大于溶栓治疗获益，是不能被临床诊疗所接受的。

　　<International Circulation>： Well， thank you very much for your time.

　　《国际循环网》：好吧，非常感谢您的宝贵时间和精彩回答。