TCT2021 | Ten-year All-cause Death After Percutaneous or Surgical Revascularization in Diabetic Patients With Complex Coronary Artery Disease

                                                                  Editor：Cheng Zhan

There is a close relationship between cardiovascular disease and diabetes, so what is the difference between coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) in improving the long-term prognosis of diabetic patients with complex coronary artery disease? At the TCT 2021 conference, Professor Patrick W. Serruys of the National Heart and Lung Institute of Imperial College London announced the 10-year follow-up results of his team's related research. This journal specially invited him to conduct an exclusive interview.
 
International Circulation: Would you please share us what is the difference between the prognosis of diabetic patients with complex coronary artery disease after percutaneous or surgical revascularization?
 
Professor Patrick W. Serruys: The first point is that there are basically three levels of diabetes. There is the one you can treat by diet. The second way, you have to take oral hyperglycemic medication. And the third one, you have to receive insulin. Of course, we also have to make the difference between diabetes type 1 and diabetes type 2. Now, in general, diabetes that depends on insulin is bad for the cardiovascular system. That is clear. You have more disease at the early stage. In many studies and registries, it has been demonstrated that bypass surgery is somewhat superior in terms of durable effects related to MACE, target lesion revascularization (TLR) and myocardial infarction in the long term, up to five years. The novelty of what we have presented is that if you go up to ten years, which is quite difficult to do because ten years of follow-up is a long process, what is important with ten years of follow-up is basically the all-cause mortality. All-cause mortality is an unbiased assessment of what is happening with the patient. We were surprised that in the ten-year follow-up of the SYNTAX study, that the curves diverged for the first five years, and then globally, if you take all the diabetic patients, the curves converged after ten years. So there is a divergence, and a convergence. Of course, at the end of the day, everybody dies, but nevertheless, we were impressed by that phenomenon. It is clear that there is still some difference in the insulin-dependent patients, but that difference is no longer significant. Why surgery would be for the first five years highly favorable, and less after that, we believe is the fate of the saphenous vein graft. This type of conduit gets worn out, and there is attrition at around 5-7 years. That might explain the alteration in the long term of the prognosis for bypass surgery. That is the new piece of information.
 
 
International Circulation: What are the selection criteria for percutaneous or surgical revascularization for these patients?
 
Professor Patrick W. Serruys: What is very important for the practitioner and for the trialist is that we all look at what I and the community of epidemiologists call average treatment effect. What is the average treatment effect? It is the fact that two curves diverge, and you end up with a difference of 5%, 10% or whatever. Then, are you going to make a decision only on that difference - the average difference between two groups? That is how we have been practicing and interpreting trials for a long time, but, as a matter of fact, you know that in the population that you have randomized, there are patients who are going to benefit from the treatment, or patients that will have an equivocal result that can go both ways, and there will be patients who will be harmed by the treatment. That is also true with percutaneous treatment and bypass surgery. So, over the last ten years, we have tried to construct a model where we can identify in that population who is going to benefit from bypass surgery and who is going to benefit from the percutaneous treatment. And vice versa, who is going to be harmed by the percutaneous treatment, and who is going to be harmed by bypass surgery. We started a few years ago in the Lancet in 2013 with the SYNTAX score, which is a mix of anatomic characters and comorbidities; and then in 2020, we have redeveloped the program as the SYNTAX Score 2020. With that score, you can identify, even in the diabetic patient, those who will benefit from surgery or those will benefit from PCI. This is a personalized prediction. Because the prediction is pretty good, you have to respect that, as there is a very good relationship between the predicted mortality and the observed mortality. That is what we are doing now with our selection criteria - we are applying the SYNTAX Score 2020.
 
International Circulation: Due to the complex coronary artery disease in diabetic patients, how to optimize the selection of stents is very important. Would you please share us your opinion about this?
 
Professor Patrick W. Serruys: We have just published in the European Heart Journal the five-year results of SYNTAX II, which is a single arm trial with a propensity comparison to the full SYNTAX done with the TAXUS stent. So it is really old-fashioned technology, but the predictions still work quite well. That is the first point. Point number two, we have in the SYNTAX II trial, first clearly made a device selection using the SYNTAX II selection, where that patient may go to PCI because the mortality at five years or ten years would be OK. Secondly, it may be a minor point, but you can use a statin before the procedure. Third point. You have to select a vessel based on physiology - QFR, iFR, FFR. You have to do your planning according to the results of  QFR FFR. If you have three lesions, you don’t have to stent all three lesions. You have to stent maybe the first one or maybe the last one, or maybe a combination of two, based on the residual iFR of QFR being >0.9. You have to use ultra-thin stents. There is no problem, that is clear. There have been three of them on the market - Orsiro by Biotronik; MiStent, also an ultra-thin stent; and more recently, the Supraflex Cruz, which is 60 microns on all dimensions. After implantation of the stent, it is good to do, at least in multivessel disease, an IVUS or OCT to show your implantation is perfect. Then what is very important is to have what we call OMT (optimal medical treatment). Aspirin and a statin are very important, and medication against hypertension, and of course, treatment of diabetes. In the SYNTAX I trial, after ten years, the curves are still diverging between the patients who received optimal medical treatment, and those who didn’t. That is the recipe - to use an ultra-thin stent. So far there have been two meta-analyses, one of them published in the European Heart Journal, showing that we need the ultra-thin stent. They have the edge in almost everything - combinations, MI, revascularization. The most difficult is always all-cause mortality, but the more of these meta-analyses you do, the bigger the numbers, and you are able to demonstrate that the ultra-thin is the way to go.