Where does this DK idea came from, or what is the rationale behind the DK idea for culotte? So the problem is that any dilation in the gilled non-stented branch causes deformation in the stem. So when you balloon towards the other branch, then it deforms the previously implanted stem. And of course, this can be corrected, it can be prevented, it can be corrected. And the correction is normally the kissing dilation. But preventing is always a predictable action with predictable outcome, while correction, it contains a certain uncertainty. So therefore, you can see here how the stent looks like in a traditional culotte. So when you open up, you place the stent, look what deformation occurs in the firstly implanted stem. Of course, you can correct this with kissing, but for correcting this with kissing, you have to achieve perfect rewiring, even in this massively deformed, hostile location of the firstly stented branch. So the uncertainty is how well you can rewire while your stent is so much deformed. And this is what we have learned from the DK crush idea, that this DK, when you perform the first kissing, that it adapts your first stent to all future deformations. And actually, it accommodates the shape of your first stent to potential future deformations. It's a kind of prevention. The second kissing will take care of the second stent while not much bothering the first stent. So what is the difference in the steps? Actually, the steps is also easy to remember. This is what I mentioned when I told you that it's just nothing else but the provisional approach. So what you do is, as shown before, stent one branch, perform the proximal optimization, do the kissing, and then you just repeat exactly the same steps towards the other branch. Put the stent, do the pot, do the kissing. So actually, it's nothing else but the steps of provisional towards one branch and the steps of provisionals towards the other branch. This is what a DK culotte is. Here you can see how it differs from the previous one. Here we perform a kissing, so there is no fluid in the balloon, but you have seen we performed. And while we put the stent, again, you see here the kissing inflation, the first stent is adapted to future deformations. And when we put the stent, nothing happens. This first stent doesn't move, doesn't deform anymore because it's fully prepared to all the potential future deformations. And it's easy to imagine that when you compare these two different techniques, in which case you can be sure that you will properly rewire the side branch. You see, traditional culotte on the left and DK culotte on the right. Massive deformation on the left and actually a nicely maintained side branch result on the right. Here it's also shown in different cases with the traditional culotte, massively deformed osteum of the side branch, while on DK it's nicely prepared and no change in the side branch of the stem afterward. Just to show you what we did in bench assessment, interestingly, when we compared the techniques there with DK culotte, much easier secondary wiring compared to DK crush or culotte. Why? Because the osteum was so well prepared that there was no issue anymore to get there with the wire. There were no hanging struts. Why? Because the first kissing already flared the stent and opposed the stent to the wall. I just stop here for a second in case you have questions we can discuss before we move on with the case. Thanks, Dr. Toth. There is one question from the chat and that is, when you are doing the first kiss, what is your protocol for balloon sizing and then how high a pressure? Balloon sizing, again, why do we do this kissing? We do this kissing because we want to avoid future deformation. If the second stent will be a 3-5 stent, then you need a 3-5 balloon towards the jail branch. What do you need in the first stent? You need exactly the size of the balloon what the first stent was. Let's say in Dr. Rapp's case, you say that the marginal was 2-5 at the end and the circumflex was also 2-5, then I would have performed the kissing with 2-5-2-5. If it was 3-0 and 3-0 branch, then 3-0-3-0. So no undersized kissing because with undersized kissing, you just miss the point of the first kiss. So Dr. Toth, can I ask you about the IVS information or intravascular imaging information? Do you want to document stent deformation before you do the second kiss or you think it should be like a mandatory step? For me, the key for imaging in these steps are the confirmation of the proper rewiring. For instance, if we come back to Dr. Rapp's case, where a relatively small stent was placed and then the proximal optimization was made to relatively large size and it was a very long stent. In this case, especially if you have any hesitation whether your wire ran perfectly, imaging is what can confirm that there is no wire behind the struts. It's always intraluminal, uroliprost, distally, and so on and so on. So these are the steps that I would confirm with imaging. I talked at the beginning about the neocorrhina issue and neocorrhina is something that we would like to minimize. How you can minimize neocorrhina? By distal rewiring. Distal rewiring, of course, there are some steps how you can be almost sure that you rewire distally just based on fluoro, but what can confirm to you is imaging. With imaging towards the main branch, you can confirm that your side branch wire is intraluminal, so in the stent all over and crossed at the very distal cell just next to the corrhina. These are for me the key questions to be checked by imaging.

DK culotte technique

dilation

stem deformation

rewiring

intravascular imaging