International Circulation: Do you agree with the use of MSCT coronary angiography as a routine test to rule out suspected coronary artery disease? Why or why not?

Prof. Lim: This is a very important health economic question as well as a scientific question. With the very rapid improvement in technology it is becoming a trend that MSCT is used to rule out coronary artery disease. This is well accepted but the problem is if you find coronary artery plaques whether or not  it constitutes disease and I think the special resolution accuracy is not good enough to make it comparable to the more invasive coronary angiography to make important clinical management decisions. So there are two answers to the question. As a routine tool to rule out disease – yes， if you want to know “Do I have coronary artery plaque”. “Do I have coronary artery disease?” is a clinical problem. So we need to distinguish when does the pathology become a clinical disease and I think CT cannot tell you that.

International Circulation: Would it be useful in helping someone to avoid a more invasive test if you could use the MSCT to just rule it out completely?

Prof. Lim: Absolutely. I think that is its best role and there are many studies， or particularly long term studies， to show that if we use conventional risk factors to estimate whether or not you have disease it is not as accurate as one simple MSCT scan now. For patients who really are interested in their health， those with bad family history to want to know whether or not they have developed coronary artery sclerosis， this is probably the main diagnostic tool.

International Circulation: Does coronary calcium score  tell you that you have coronary atherosclerosis?

Prof. Lim: The clear answer is yes. The more the calcium score， the more the coronary atherosclerotic plaque burden. That does not make it disease. So this is a very important clinical point to stress that the presence of plaque does not always constitute disease. The more calcium you have， if you have plaque and if you have disease， and other clinical manifestations of atherosclerotic plaque， it is more stable. So in fact calcium is very protective against the more dangerous acute coronary syndrome， because they represent mature plaque so the score will tell you that perhaps you have a heavy burden of coronary atherosclerotic plaque and maybe it is more stable. I think that is the value of CT calcium score.

International Circulation: For patients who are presenting with suspected acute coronary syndrome， when do you think it is best to do CT coronary angiography and who are the best candidates and what are perhaps the shortcomings?

Prof. Lim: This is the paradoxical issue of MSCT. In the acute coronary syndrome patient， the higher the risk， the more urgent interventional therapy will benefit them. The high risk patients usually have vulnerable plaques which are low calcium score but low density CT plaques. When a patient presents with acute coronary syndrome there are usually other co-morbidities and the most important one is renal impairment. So the CT for acute coronary syndrome has two problems. One is to delay urgent treatment of the high risk patient. Secondly to add radiational dosage to the therapy and finally the contrast used to make those with renal impairment even higher risk in interventional therapy. So it cannot become a routine tool at the present time with the present technology， but I think with a faster and faster scan and better and better resolution， if you can do it before you go to intervention， it has great advantage. So I think there is a role， but the current technology prevents its widespread use to detect plaques which need to be intervened， because of additional radiation， additional contrast risk to the acute coronary patient.

International Circulation: What about its use in evaluating in-stent restenosis?

Prof. Lim: That’s my hobby-horse at the moment， which is the paper I presented at this meeting. Clearly it would be the gold standard or the holy grail to have a non-invasive way to evaluate both the presence of coronary disease as well as the success of your therapies such as putting in a stent especially in a position like left main. So there are papers to support the use of invasive coronary angiographic follow-up for left main stenting. You can substitute that using non-invasive CT. So I presented an initial experience to use a quantitative score of luminal contrast attenuation within the stent to see whether we can use this more objectively to predict stent patency and a preliminary answer， which is my conclusion of the talk this morning， is that yes it is feasible but we need more objective data and we need correlation with the gold standard of invasive coronary angiography to evaluate in-stent restenosis. I’m sure this will come very quickly.

International Circulation: Obviously when we have meetings such as CIT and TCT， there is a lot of real training that is going on here; we have live cases， simulators. Can you talk a little bit about how are we training the interventional cardiologists and training in general? What are your views on some optimal ways to go about it?

Prof. Lim: I have been involved with the training of interventional cardiologists in China from the very beginning， more than 20 years ago， as well as training of  our cardiologists and interventional cardiologists in Australia and Singapore. I think to be a good interventional cardiologist one first has to be a good clinical cardiologist so bedside training is paramount. A very systematic formal program of training， which I think America has and Australia has， less so in some of the developing Asian countries. It is now well established that if you have a very strict criteria for training with emphasis on clinical training， and then the skill training， eventually you turn out the best interventional therapeutic doctors. Systematic training in theory， skills and finally very close follow-up of long term results of research frontiers will make the best interventional cardiologists.

International Circulation: You have experience in China， Singapore and Australia so at present， what is the status and your evaluation of the training situation in China and constraints or things that could use some further development?

Prof. Lim: China has fast changed from a developing to a developed country especially in scientific technological arenas such as interventional cardiology which is very specialized. It has to move in the same direction as the Western community in achieving an international standard of training and I think the Health Ministry is actually starting to look into this issue now and there are accreditation processes for training doctors， for trainers. Perhaps now they have to focus on training criteria for trainees， which I referred to earlier， in that perhaps the training of a clinician is slightly different in China compared to Australia or Singapore in the West.