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In this next video, we're gonna talk about use of tavr, uh,

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in the valve in valve setting. Um, so what does that mean valve in valve? Well,

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basically that means putting a TAVR device inside of a surgical aortic valve

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that was previously placed.

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So it turns out that 70% of surgical aortic valves are degenerated at 20 years.

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Um, so there are a lot of patients out there in the world with surgical aortic

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valves who need repeat valve replacement after their valves basically wear out.

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Um,

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and so TAVR devices can be deployed within the inner ring of the surgical valve,

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uh, and that avoids an additional surgery for the patient.

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The important thing for us though, uh, as imagers and, uh,

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those of us who are assessing these patients prior to the procedure,

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we need to know that the risk of coronary obstruction is much higher in patients

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who are valve and valve, um,

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and happens about 4% of cases and is four to six times higher. Um,

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for that reason, coronary heights, sinus widths,

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and the distance from the virtual valve ring to the coronary ostia,

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which I will explain are important for preoperative planning. And, and,

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you know, obviously minimizing the risk for the patient.

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So this is, uh, a picture of a typical stented bioprosthetic valve. Um,

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this is, uh, from, uh,

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this article here in circulation and there are a lot of different diameters here

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that are pointed out. But the key one for us is this inner internal diameter,

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and that's basically the diameter from the edge of the whole ring that supports

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this valve structure. Um,

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that's gonna actually serve as the sort of minimal diameter,

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that constraining factor that's gonna, uh,

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limit the size of the TAVR device that can be placed. So the inner ring, um,

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which, uh, corresponds to this metal ring here on the CT image,

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that's again, the piece of the device where all the, uh,

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structure of the valves are, um, basically anchored.

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And this is gonna be where the TAVR device sits.

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So when we're performing a TAVR evaluation, this is gonna serve as our basal,

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uh, annular plane. Um,

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and from that most inferior annular plane of that surgical ring,

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we're gonna perform our measurements, uh, coronary heights, et cetera. Um,

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the other dimensions that you see here are, um, less important for us.

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Um, these, um, again, don't create the constraints, um, that will, um,

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tell us what the sizes of the device that needs to go in. Uh, one note,

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the aortic profile height is, you usually have these posts, uh,

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on which the, um, leaflets are suspended.

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Turns out if the posts sit below the coronary origins,

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usually the risk of the patients can be quite low. Um, whereas if the coronary,

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uh, origins are below the posts,

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then that's where you need to start looking at these other, um,

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measurements that I'm gonna describe.

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So how do we do these valve and valve measurements? Well, again, as I mentioned,

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the inner surgical ring is used as the annular plane, so, um,

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we use that as our anchor point and we perform the same measurements.

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These annular measurements, to be honest,

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Aren't quite as important in these patients because these, um,

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numbers are known. You know, they, you put in a device,

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the device dimensions are known,

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and generally those can be used to decide on the size of the TAVR that's gonna

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go in. Um, however, the other measurements, the coronary heights,

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the sinus widths, they're all based on the location of a and inter plane. So we,

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it's obviously important to identify the anulus in these cases.

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And then there's this other new concept that's unique to the valve and valve

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measurements, and that's this, um, valve to coronary distance. Um,

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and it's a, a measurement that's made in the short axis plane. Uh,

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and this is a measurement from a what's considered a virtual transcatheter heart

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valve to the coronary osteo.

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You create a an r o I that simulates the dimensions of the desired valve and

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centered on the valve post.

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So you make an r o i that goes through the valve posts,

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and then you measure from that r o i to the coronary osteo,

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and that gives you your valve to coronary distance. Now,

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to be as accurate as possible,

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you ideally would wanna make the diameter of the r o I match the dimensions

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of the intended valve. So, for instance,

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the size of a core valve,

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if you're gonna put in a core valve or a sapien valve is known that outer

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diameter is known. You could get that, uh,

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information from the manufacturer's website. It's,

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it's actually readily available. Um, use that, uh,

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diameter information to create your R O I and then measure out to the coronary,

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uh, osteo. Um, some of the, uh, different three D software that's used,

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um, to, uh, evaluate patients prior to uh,

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TAVR also includes, um, some of these valves, uh,

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as like a shell that you can overlay onto the images if you have access to that

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type of software. And you can use that to perform the same measurements.

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Ideally,

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you want this number to be more than four millimeters to minimize risk of

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coronary, uh, obstruction.

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And here's just an example of an image post valve and valve. Um,

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this is what they look like. This patient had the, uh,

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core valve device and you can see, like I had mentioned, that this metal ring,

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um, which is used to hold up the valve apparatus that serves as our annular

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diameter. And this sort of like the,

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the narrowest part that's gonna define the size of this valve,

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and you can see the core valve nicely opposed up to that angular ring.

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So you have a really nice result.

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And this is a slice at the level where we would measure the valve, um,

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to coronary osteo distance. You can see here that we have nice, um,

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space around the valve itself, um, to the coronary osteo. Um,

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so this is a really great result and this is what you expect to see, um,

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after valve and valve.