<International Circulation>: Thank you. When STEMI (ST elevation myocardial infarction) patients present later than 12 hours after the onset of symptoms， whether they can benefit from PCI or not is closely related to the existence of viable myocardium. How would you estimate viable myocardium rapidly and accurately in clinical practice?
Dr. Mehilli: If a patient has a myocardial infarction， it is difficult to put the patient in MRI or to do sestamibi accurately. Even if they are late comers， we take them to the Cath lab to open the artery. The measurement of viable myocardium is important at the end of the interventions. We can measure this with the technetium sestamibi， which is effective but means more radiation for the patient. We use just MRI to measure not only the infarct type， but also the peri-infarct edema. This is the part of the myocardium， which can be salvaged during during the weeks and months after the intervention.

　　《国际循环》：如果STEMI患者起病12小时之后就诊的话，能否从PCI中获益是否与有无存活心肌紧密相关。临床实践中如何快速、准确地测定存活心肌？
Mehilli博士：对就诊的心梗患者很难实施MRI检查或司他比锝即刻进行评估，因为这些是急性心梗患者。因此，即使是就诊较迟的患者，我们也尽快将患者送入导管室并开通梗阻血管。在介入治疗的最后测定存活心肌是重要的，也就是估计梗死面积。司他比锝心肌灌注显像是测定存活心肌的一个非常好的方法，但是对患者的辐射多一些。我们也可以用MRI来测定，不仅可以确定梗死面积，还可以观察梗死灶周围的水肿。水肿区是在干预后数周乃至数月内可被挽救的心肌。

<International Circulation>: For my last question， in 2011 the ACCF (American College of Cardiology Foundation) and AHA (American Heart Association) SCA (sudden cardiac arrest) guidelines for PCI were modified. The time window of transfer PCI was modified from 90 minutes to 120 minutes. In your opinion， do you think the time window could extend again in the future and what do you think is the longest time window possible for primary PCI?
Dr. Mehilli: I hope that guideline authors would accept this tool and prolong the time from symptom onset to the intervention because it salvages myocardium and can save lives， even if you do it later after the symptom onset. The important thing for the patient is to be treated， because the later patients are higher-risk patients. They are often older or female patients with more co-morbidities， and this part of the population would benefit from the intervention， independent of when the arteries are occluded. Every time we can win something. That is why I would hope that this window will be expanded. We cannot say there is a time in which you cannot do PCI.  With PCI you can open the artery in more than 90% of the cases. Sure， there are low risk patients in with just one diseased artery and the natural collaterals have been developed. Patients， for example like in the OAT trial， are low risk patients. These patients are symptom free， with no sign of ischemia and perfect collateralization. For them， no PCI is needed. However， these patients are rare.

　　《国际循环》：2011年，美国心脏病学会基金会/美国心脏协会（ACCF/AHA）修订了PCI猝死指南。转运PCI治疗时间窗从90分钟延长至120分钟。未来这一时间窗是否会再次延长？你认为直接PCI最长的治疗时间窗可能是多少？
Mehilli博士：我期望制定该指南的同仁能够延长从发病到PCI干预的时间窗，因为PCI能够挽救心肌和生命，即使是在发病较长时间后实施PCI的情况下。对于患者来讲，重要的是得到治疗，因为发病后较晚就诊的患者属于高危患者。他们通常年龄较大或是有更多并存疾病或是女性患者，这些患者能够从PCI治疗中获益，无论他们的动脉是什么时候阻塞的。每一次PCI干预都能够有所收益。这就是我期望PCI治疗时间窗能够延长的原因。我们不能说发病超过一定时间就不能做PCI了。PCI可以使90%以上的患者动脉开通。当然，有一些单支动脉闭塞的低危患者，有侧枝供应。例如OAT（闭塞动脉试验）中的患者就是低危患者。这些患者如果没有缺血症状的话，可能不需要实施PCI，只给予药物治疗即可。但是这只是极少一部分患者。　

　　<International Circulation>:  Alright， thank you very much.
Dr. Mehilli: You’re welcome.