International Circulation: One of your talks during CIT 2011 will involve the 2nd generation of drug eluting stents (DES). Please summarize the main advantages of these 2nd generation stents over the previous generation?
　　Prof David Kandzari: I prefer not to differentiate between the drug eluting stents as to regards to whether they are first， second or more advanced generations. I  Think what we have learnt is a broader theme from comparative DES trials is that not all stents are created equally whether they  are polymers， comprised of metal or contain drugs which are anti-proliferative. For the current newer second generation drug eluting stents we have learnt some important lessons from the previous generation. The first is that I would to emphasize that not all stents are created equally. Through long term follow from previous comparative and more recent comparative trials evaluating first and second DES we have learnt there are important differences in these stents with regards to not only angiographic efficacy such as late lumen loss but more importantly patient based clinical outcomes such as the need for repeat revascularization， death， myocardial infarction and stent thrombosis. Secondly， not all stents will behave as they do in clinical trials as they do in clinical practice. In other words not all clinical trials are representative of how a stent will fare in real world practice. We have learnt this from the 2006 FDA panel meeting for example that off label use may be associated with worse outcomes.  This more importantly enforces the idea that we should follow the outcomes of these patients treated in broad unselected patient populations. This is because more recent studies suggest that DES might be associated with lower mortality with improved outcomes. Thirdly， is that given the outcomes of DES today and the lowest rates of repeat revascularization we have ever observed with everolimus eluting stents and sirolimus -eluting stents as well as the lowest rates of stent thrombosis and cardiovascular death， the challenge of raising this bar will be quite difficult. Future stents such as ones with a bioresorbable polymer or a bioresorbable stent altogether will find it very difficult to demonstrate any superiority.