International Circulation: Dr. you talked about high risk patients; is the high risk because an invasive surgery would cause trouble to them?
国际循环：您所提到的高危患者，是否指外科手术会给他们带来很多麻烦的那些患者？

Prof. Robert O. Bonow: These are patients who are felt to be high risk for the early post- operative complications including post- operative death.   This is based on a number of factors using standard risk assessments: the Euro score the STS Score and incorporates several factors including age，  cardiac function，  real function， lung function， etc.  All the co-morbidity that can add up to people being at considerable risk for surgery.  So in principle we are talking primarily of older people who have substantial co- morbidities， who， based upon numerous data sets would be at a high 30- day mortality risk.
But just to add to that: this is opposite of what happened in the development of coronary angioplasty.  Coronary angioplasty， when it began， took the less complicated patients; patients with single- vessel coronary disease， not multi- vessel disease.  So this is just the opposite.  Here we are talking the patients who are at the highest risk ， because the alternative – which is open heart surgery to replace a valve – is well established，  low risk，  and it would be hard to subject a patient who is otherwise a low risk for surgery for an experimental device such as this.  So the understanding is we are taking now the highest risk patients for these new devices ， realizing that since they are high risk there will be mortality related to many of the co-morbidities.  So trying the assess mortality from these early studies would be difficult.  So primarily what is be evaluated is the function of the valve， the durability of the valve and the technical success in implanting valves. 
Prof. Robert O. Bonow: 这些患者术后早期的并发症发生率非常高，包括术后死亡的风险。这是通过标准风险评估测定的一系列危险因素：Euro分数、STS分数并采用多种因素综合评估，包括年龄，心功能，肾功能，肺功能等。所有上述可能导致的死亡率需要在术前风险中综合考虑。因此，在原则上我们需要对较年老的患者综合考虑其并发症风险，多项研究显示此类患者30天的死亡风险仍然是很高的。

需要补充的是：TAVI与冠状动脉成形术的发展情况相反。冠状动脉成形术刚开始时，可以选择病变不太复杂的患者进行介入治疗，比如选择那些单支病变的冠状动脉疾病患者，而不选择多支血管病变者。而TAVI刚好相反，我们讨论的患者都是最高风险的患者，低风险的患者可以选择开胸手术，很难找到一个低风险的患者来进行试验性的TAVI术。因此使用此新装置的患者都是高风险的患者，并发症高导致死亡率高。从这些早期的研究中很难评估死亡率，因此目前主要评估的是瓣膜的功能，瓣膜的耐用性和瓣膜植入的技术成功率。