International Circulation: What makes these grafts for susceptible to stenosis?
　　Dr. Dean: It has been debated. It has something to do with the placement of conduits， such as putting a vein into the arterial system. A graft of this kind was never designed for that type of pressure. There can be a host of technical issues from the standpoint of early graft failure， while late graft failure has more to do with having a conduit that is not designed for a particular environment. This is likely why arterial grafts - particularly the LIMA graft – have superior graft patency. I think it is an interesting question and it is something that interventional cardiologists debate with our surgical colleagues from time to time. We have restenosis as our Achilles heel， they have vein grafts. A lot of us are moving towards arterial conduits that can be placed in a patient and then using stents to take care of vessels that cannot have arterial conduits placed. I think coronary stents are much more likely to be as good as， if not better than， a vein graft over the long term. Drug-eluting stents can certainly match the graft patency long term in SVG.
　　《国际循环》：哪些因素使SVG易发生狭窄？
　　Dean教授：对此还有争议。与SVG放置的位置有关。SVG放置于动脉系统，它从未承受动脉系统的压力。早期SVG移植失败，可能是由于一系列的技术性问题，而晚期SVG移植失败，更多地与SVG不适合特定的环境有关。这就是为什么动脉桥血管，尤其是乳内动脉（LIMA）通畅度更好的原因。我认为，这是一个有意思的问题，这是介入心脏病专家和外科同事们一直在争论的问题。SVG再狭窄是致命的弱点。很多医生转而给患者应用动脉桥血管，不能放置动脉桥血管的患者则置入支架。我认为，冠状动脉支架置入的远期效果即使不比静脉桥血管，也可能与其相当。当然，药物洗脱支架的长期血管通畅率与SVG相近。