Intravascular Ultrasound (IVUS) Consensus Guidelines

[Dr. Sabeen Dhand]
Let's talk about IVUS. I personally used to use IVUS sporadically when I first started my practice, and about a year and a half ago, we upgraded our system and got a really much more newer generation of IVUS, which has been a lot better. Are you using IVUS for both artery and veins and everything far in between?

[Dr. Eric Secemsky]
Yeah, it's always interesting to talk to an interventional cardiologist about IVUS, because most interventionists in training right now, or in practice, have a specific focus on intravascular imaging during coronary procedures. We use IVUS liberally. I mean I would say in my own practice, 70% to 80% of my coronary interventions are performed by IVUS guidance. In the world of coronary intervention, you're applauded when you use IVUS.

It's something that you wear as a badge of honor, for having taken the extra time to use a device that is making the procedure safer and outcomes better. I spent a lot of time using IVUS in the coronary. When I trained on venous work, we did a lot of IVUS on venous work, and then we had a smattering of IVUS during our peripheral artery interventions. That wasn't as routine back when I was training, years ago now.

But again, as you use this device more and more, you get more comfortable with it, to the point where I don't even feel comfortable doing some procedures without IVUS. It started to become kind of light bulb to say, "I should be thinking about this more in my arterial interventions, doing a little bit more on the venous interventions, exploring where else this device can really help optimize care for patients."

Really, the goal, obviously, is to make our procedures durable, and particularly in the endovascular world, I think this was really a moment for me to say, "I think I can do better with this device as a guidance."

[Dr. Sabeen Dhand]
When you're using it for coronary, I mean what are you looking at in IVUS? Are you just looking at sizing? Tell me, what are the things that are going through your head one, two, three, four, five, when you're looking at an IVUS image?

[Dr. Eric Secemsky]
Yeah, in the coronary space, it's pretty well regimented into how we perform IVUS. On the normal case, you cross the lesion with the wire, and you IVUS. On your IVUS, you get a couple of things. You get lesion length, so you get healthy to healthy reference. You get the vessel diameter so that you can size your pre-do balloon, and then we always stent in the coronary, so our coronary stent. Then you get an understanding of the plaque composition.

In particular, for coronary, it's calcium. How much calcium? What's the arc? If it's 360 degrees, we know that we probably have to do something to modify that calcium, to get a stent in. So every coronary intervention that uses IVUS kinda follows that same routine. We're very regimented in the coronary. When you look at coronary cases, you could be across the country, or even the world, we do things almost the same, in Boston as in the Netherlands, or where else.

It's really interesting because in the peripheral, we know that's not the same, and we'll talk a little bit about that later. Then you do your ballooning. Usually, if you feel comfortable with how your balloon looks, you put in your stent, and then you IVUS again. When you IVUS again, you're trying to optimize the stent at position. You want to make sure that there's no malposition, or under-expansion.

Then, for me, you're looking at the edges of the stent and make sure there's no dissection. When I walk away from a coronary procedure with a clear IVUS run, showing a good stent, no problems, I'm sleeping better. I always joke about this to my fellows, because we always get these calls, "Oh, they're having a little bit of chest pain, or their blood pressures--" Listen, I feel very confident based on how I left the lab, that that stent's looking good.

[Dr. Sabeen Dhand]
That stent is perfect, basically.

[Dr. Eric Secemsky]
That stent's per area. Got my stamp on it.

[Dr. Sabeen Dhand]
Now, a little bit of a peculiarity, because now I'm using IVUS almost on every intervention, too. When you're measuring the size in a coronary, or what we're going to extrapolate to peripheral soon, I mean you see the round ring of calcium. Usually, most arteries are calcified, what we're treating. Are you measuring on the outside of the ring, on the inside, in the middle? It makes a difference. I mean, we're talking about 0.5 mm, or a millimeter, which makes a difference in our sizing. So where exactly are you measuring?

[Dr. Eric Secemsky]
Yeah, that’s a continued debate about what's the right way. I think we're both on the same page for arterial sizing. Ideally, you're trying to identify the three layers of the vessel wall. In the coronary, we're really looking to size to that black stripe that happens behind the intima. That's the elastic membrane, and you want to size to that. Now, again, in the corner, though, it's a balloon-mounted stent and you deploy it, that's where you deploy that.

If you're sizing to the elastic membrane, that's fine, but you're doing that differently than when you have an outward force from a self-expanding stent, or if you're not stenting, just ballooning. A lot of times, minus the calcium, if I'm making a measurement of the arterial vessel in the periphery, I'm usually doing a luminal diameter, or extending it maybe a quarter millimeter longer than the luminal diameter of a healthy reference. That's pretty much how I do my measurements.

Keeping in mind that, again, a lot of the self-expanding stents we'll use, but even for one-to-one sizing, or 1.2-to-one sizing for balloon angioplasty.

[Dr. Sabeen Dhand]
Sometimes, I'm a little confused, like, "Oh, should I go--? What part of the vessel should I measure?" Now it's nice, I can measure myself on the system that I have, where I have the tablet in my sterile field. Before, I was using this trackball, and not I was, my techs would use it, and they would measure from the thigh skin to the middle of the vessel. There was no control of it.

[Dr. Eric Secemsky]
It makes a world of difference, how much easier you can do it. Again, I'm a little bit spoiled, because I have a fellow that's usually doing the pullback, and I'm just making bookmarks. I'm telling them to stop, I’ll fluoro-save a healthy reference or section on IVUS. The whole thing goes really quickly when you get used to it. My humble opinion is that I make a smarter device selection after that.

Usually, I don't necessarily dilate anymore. I'm just using one balloon that sized off IVUS. It definitely makes my procedure more efficient.