Editor's press: Recently, the europcr 2021 Congress has been closed smoothly , and the results of the EBC main study presented at this conference put forward different views on the choice of the operative strategy in patients with true left main bifurcation lesions than the results of the DKCRUSH-Vstudy.Then, exactly how the treatment strategy was chosen for this subset of patients, we invited Prof. David Hildick Smith for a special interview on relevant issues for this new study.
International Circulation: At this conference, you introduced the latest results of the EBC MAIN study. Would you please share us the characteristics of the clinical outcomes of the two groups?
Professor Hildick-Smith: The EBC MAIN study was a randomized study comparing provisional single stenting versus systematic dual stent implantation in patients with left main stem bifurcation coronary artery disease, two bifurcations, and significantly sized vessels in both limbs. That was the essence of the study. It was conducted in thirty different centers in eleven European countries. It took around 3-4 years to recruit, so it was quite a long period of recruitment getting these patients. The primary endpoint was a one-year analysis of a composite of death, MI, and target lesion revascularization. We looked at that as the primary outcome at one year. What we found with the study was that in the provisional strategy where patients had a single stent followed by proximal optimization, and then kissing balloon inflations, and then, if necessary, another stent, the primary endpoint was met in 14.7% of patients; whereas in the systematic group who all had two stents, the primary endpoint was met in 17.7% in one year. Now that is numerically different, but it didn’t meet any statistically significant difference. The only component of that which looked to have any significant difference perhaps was that for target lesion revascularization. The repeat event rate was 6% in the provisional group, and 9% in the systematic group. That was closer to statistical significance.
International Circulation: Which patients in the planned single-stent strategy group ultimately received dual-stent treatment?
Professor Hildick-Smith: In the provisional strategy, obviously there is the single stent, there is the proximal optimization, there is the kiss, and then there is the decision about a second stent in this study. You could have a second stent if you still had severe narrowing at the ostia of the side vessel, or if there was slow flow, or if there was threatened closure, or dissection. It was very much open to discretion to put in a second stent. In the end, most of the cases were stented either because of persistent narrowing in the side vessel, or because of type A or further dissection. Interestingly, that only comprised 20% of cases. In 80% of cases that were randomized to the provisional strategy, only a single stent was implanted; and in the other 20%, a second stent was implanted followed by further kissing inflation.
International Circulation: In view of the results of this study, for patients with true bifurcation left main stenosis who need intervention, should we choose a gradual layered temporary stent strategy or a conventional double stent strategy?
Professor Hildick-Smith: That’s a good question. I think it depends very much on the anatomy. If we compare the broadly neutral results in this study with previous studies that have shown better outcomes with DK Crush, anatomically, these have been different patients. For example, in the DK Crush, the SYNTAX score was higher in those studies than in EBC MAIN. Similarly, the extent of the disease was greater in the DK Crush studies – an average of 16mm of side branch lesion length versus 7mm. So I think the answer to your question depends quite a lot on the anatomy, and depends, therefore, to a certain extent on the geography, and the philosophy of the operator. In the European centers, it is very common to have only a certain extent of disease in the side vessel, and therefore, the provisional strategy is to be preferred. In patients where the side vessel disease length is significant in its own right, then it is broadly speaking inevitable that you will end up with two stents. Therefore, to do it right from the outset may be perfectly reasonable, or to do a provisional strategy and see how you go and put a second stent in when it is necessary is also perfectly reasonable. It still means that certainly for European patients, we should ideally be looking at a provisional strategy unless there are particularly strong indications for dual-stenting upfront.
International Circulation: Would you please share us the next research focus of the EBC MAIN study?
Professor Hildick-Smith: That is an interesting question. I think there is quite a lot within the study to look at. We need to look at the influence of intravascular ultrasound on outcomes. We will look at the disease complexity, perhaps looking at the definition criteria for the definition of bifurcations. We may go back and revise the study in that manner now. We may be in a position to do meta-analyses with other studies. We haven’t decided yet, but there will be a number of options, and obviously, as is usually the case, the minute you do a study and see what appears to be an answer to one question, it opens up a whole new bunch of questions that can be studied afresh. I think there is work yet to be done.
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