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In this case, I'm going to show you how

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to analyze an anomalous coronary artery.

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So this is an example of an anomalous coronary artery,

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but we're going to appreciate a few principles.

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First is where does the coronary artery arise?

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So here is the left main,

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and that gives off the LAD and

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circumflexus, a very short left main.

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And if you see this twig over here,

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that is the anomalous artery.

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So with anomalous arteries,

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there are two types of courses.

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One is the interarterial course, which is also

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called the malignant course, but there's no need

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to call it malignant, just call it interarterial.

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And the other is the retroaortic

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course, which is behind the aorta.

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So why is the interarterial course

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more dangerous?

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Because the artery is squashed between the

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aorta and the pulmonary artery of the right

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ventricular outflow tract, both of which

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can contract and push against the artery.

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Retroaortic course is between the aorta and

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the left atrium, and the left atrium is not

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really a structure that contracts very strongly.

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So there's more shear on the anomalous

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artery when it's between the aorta and the

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pulmonary artery, or some sort of force.

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But more than that, what's important as it

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is in this case, and I'm going to magnify

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this, is the angulation of the artery.

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So you can't even see where it comes off,

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but you know, it comes off somewhere here.

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So, if you imagine that, you know, you're traveling

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in a car, and this is a road, and somewhere here

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you need to enter the car, you have to swing at

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a very acute angle, almost a hairpin bend, and

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that hairpin bend is what makes this anatomy

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high risk for causing ischemia in its territory.

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It's not coming out nicely like the left main; see

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how nicely it comes off, you can map, or the LAD.

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It's coming off at an acute angle, and that's the

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most important thing, is the angulation of its origin.

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And as a result of its angulation, a

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portion of it travels in the wall of the

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aorta, so it has an intramural course.

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Coronary arteries generally do not travel in

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walls; they travel in the subepicardial space.

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They skirt walls, like this

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LAD is doing, but they don't.

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They have fat on both sides; they're

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very important arteries, they have an important job.

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And they are cushioned from

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the contraction of the wall.

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Here, you're not.

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Here, the RCA has that angulation as it comes off.

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Normally, the RCA comes off somewhere

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around the anterior position.

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Here it's coming off the left cusp.

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So this is a high-risk anatomy.

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The fact that the RCA is nicely pacified distally

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doesn't mean that it's not high risk.

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Meaning that distal pacification can still happen

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very nicely despite having proximal issues.

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Thank you.