International Circulation: How often or how many patients do you think fit into both “appropriate for TAVR” and “futility” groups?
Dr. Leon: That is difficult to estimate. Let us look at the penetration of TAVI in Europe. In the high-volume centers， about half the aortic valve replacements are being done with TAVR. If you look at 11 European countries the penetration rate for appropriate patients is about 25% of patients that could be candidates for valve replacement: people over the age of 75， with severe aortic stenosis who are symptomatic. That is increased by a factor of 5 over the last several years. That is rapidly increasing. There are two studies right now， one is called PARTNER2A and the other is SURTAVI which monitor moderate risk patients. The inoperable patients probably represent 10% of the AS patient cohort， another 10% would be the upper decile of high-risk， but operable patients， then there is another 25% of patients that are in the moderate risk， and then there are low risk patients. We would not recommend this for low-risk patients. For moderate-risk patients， there is enough equipoise to suggest that a randomized trial is appropriate. That is what we are doing. We have already enrolled close to 800 patients in the PARTNER2A study.

　　《国际循环》：你认为有多少患者既可纳入“适合TAVR”又可纳入“无效”群体？

　　Dr. Leon：这是难以估量的。让我们来看看TAVI在欧洲的普及。在高容量中心，大约一半的主动脉瓣置换术是采用TAVR做的。在11个欧洲国家，合适患者的普及率为瓣膜置换术候选患者（75岁以上者，有症状的重度主动脉瓣狭窄患者）的约25％。也就是说在过去几年期间增加了5倍，即迅速增加。现在有两项研究，一项称为PARTNER2A，另一项是SURTAVI，后者监测的是中危患者。不能手术的患者大概占AS患者队列的10％，另外10％是属于上十分位数的高危但可手术患者，有另外25％的患者是中危，然后还有低危患者。对低危患者，我们不推荐这个。对中危患者，有足够的证据提示，进行一项随机试验是适合的。这也正是我们所在做的事情。我们在PARTNER2A研究中已经纳入了近800例患者。

International Circulation: There was an article from Belgium discussing the economic feasibility of TAVI in high-risk groups. Could you please comment on this article?
　Dr. Leon: It was two economists and it was a controversial article with much confusing data. Belgium is an interesting country. They have markedly more sites performing TAVI per unit population than any other country in Europe. They also have by far the fewest number of cases done per site of any country in Europe. It is not clear what their points are. The reality is there are careful cost-effectiveness studies in progress. One that we did is part of the PARTNER trial with David Cohen. Both inoperable and high-risk patients clearly demonstrate cost-effectiveness. Another confirmation came from two groups in the UK—just presented at London Valves Meeting—again looked at inoperable and high-risk patients and again showed that it is cost-effective technology. I do not know how to react to the articles contention that it does not provide sufficient value or that TAVI is too risky. This is a life saving procedure. You do not need to treat many patients to save a life. There are very few things we do in medicine that allow us to say that. One of the problems is that patients who are not treated die quickly. The problem with cost-effectiveness studies in that population is that it is very cheap if you die quickly. These elderly patients with comorbidities are expensive to keep alive， independent of TAVR. This needs to be viewed from a societal perspective.

　　《国际循环》：有一篇来自比利时的文章讨论了在高危人群中TAVI的经济可行性。您能否对这篇文章进行评论？

　　Dr. Leon：这是两位经济学家，这是一篇有争议的文章，数据非常混乱。比利时是一个有趣的国家。与任何其他欧洲国家相比，他们每单位人口开展TAVI的中心显著较多。然而，到目前为止，在欧洲任何一个国家中，他们每个中心的病例数量是最少的。尚不清楚他们的观点是什么。现实是，周密设计的成本效益研究正在进行中。其中之一是David Cohen所做的PARTNER试验的一部分。不能手术和高危患者都明确证实了成本效益。另一个确认来自英国的两个群体--刚在伦敦瓣膜会议上汇报过--还是观察的不能手术和高危的患者，且再次证明它是具有成本效益的技术。对文章争论，我不知道如何作出反应，它并未提供足够的价值或者TAVI太过危险。这是一个挽救生命的手术。您不需要治疗很多患者就可以挽救一个生命。在医学领域，我们能够这样说的事情非常少。其中一个问题是，未治疗的患者很快死亡。这一人群中成本效益研究的问题是，如果很快死亡那么花费自然非常少。这些有合并症的老年患者活着的代价是昂贵的，独立于TAVR之外。这需要从社会的角度来看待。