International Circulation:   Would you go over some of the fundamental elements for the success of TAVI? That is， those things that the people implementing TAVI need to be cognizant of as they move forward?
国际循环：您能给我们介绍一下成功的TAVI基本的要素有哪些吗？也就是说，我们在应用TAVI时需要认识到的问题是什么？

Prof. Greg W. Stone:  Right now TAVI is being reserved for those patients who are at very high risk for alternative aortic valve replacement by surgery or those who are just inoperative.  We have to remember that surgical aortic valve replacement is one of the most successful cardiac surgeries there is.  The morbidity and mortality rates are reasonably low in good operative candidates and the valves have been shown to be very durable， anywhere from 10-15 years or more in selected patients.  Right now the procedure is being done primarily in patients who are not good operative candidates or who are very high risk for surgery.  When we look at patients who might be candidates for TAVI， there are multiple different parameters we look at such as the peripheral vasculature， which is probably the number 1 limitation because the devices now are 24 French for the Edwards system or 18 French for the Medtronix system.  The peripheral vasculature cannot be heavily stenotic， heavily calcified， or tortuous.  Vascular complications have been the most common complications.  We have to carefully measure the aortic annulus size and the aortic root to see that it matches the dimensions of the device that we are going to be implanting.  There are multiple other specific technical and patient inclusion/exclusion criteria.  If the vasculature is too severely tortuous or diseased then we can consider a surgical， trans-apical approach， which is done through a mini-thoracotomy.  However， this is still surgery where the patient is under general anesthesia although not cardiopulmonary bypass， and carries some risks associated with the left ventricular incision that needs to be made， as well as issues with healing.  It is an alternative， which is increasingly being used as well. 
Prof. Greg W. Stone: 目前TAVI仅用于进行外科替代主动脉瓣置换术有很高风险的患者，或不起作用的患者。我们必须记住，外科主动脉瓣置换手术仍然是最成功的心脏手术。在状态好的患者，其发病率和死亡率都相当低，并且瓣膜维持时间很长，一般10~15年，在某些患者更长。现在该方法主要用于不能耐受手术的患者，或者手术风险很高的患者。当我们认为某患者适合进行TAVI时，我们会参考很多参数，如周围血管，这可能是排在首位的限制条件，因为目前Edwards公司是24 F或者Medtronix公司是18 F。外围血管不能有重度狭窄，重度钙化，或曲折。血管并发症是最常见的并发症。我们必须仔细测量主动脉瓣环的大小和主动脉根部，以确定是否符合我们将要植入装置的尺寸。还有其他多种具体的技术和患者入选/排除的标准。如果血管严重曲折或有病的话，那么我们可以考虑手术方法，它通过一个小的开胸进行操作。不过，这仍是手术，尽管不是心肺转流术，但患者在全身麻醉的情况下，有与左心室切口相关的一些风险，以及愈合的问题。这是选择之一，目前应用也越来越多。