After watching this video, you will be able to recognize hemodynamically significant aortic regurgitation using transthoracic echo.
This video was taken from our hands-on and CME accredited Echocardiography Essentials course.
[00:00:00] If you've got aortic regurgitation, you need to think why is this aortic valve leaking? You need to think is it the valve or is it the aorta? Because an aortic valve may leak because there's an abnormality with the valve itself, be it degenerative or bicuspid or rheumatic or have endocarditis but it may also leak because the aortic root is dilated, so it stretches the valve apart and the cusps can't meet and so they leak. We'll talk about dilated aortas in another lesson. The aortic regurgitation
[00:00:30] is assessed in exactly the same ways in both situations. So, we're going to look at some quick ways to assess aortic regurgitation as you scan. You may want to get a more detailed or complex study done by an expert if it's important for the patient's management. So, let's look at this parasternal long-axis view. Here, you can see in this bright color, which is a jet of aortic regurgitation. So, I'm going to look at this in quite a lot of detail. I'm going to look at the neck to the narrowest bit of the jet, right up at the valve here. Then I'm going to look at the jet, as it moves into
[00:01:00] the outflow tract. I'm particularly going to focus about a half to a centimeter away from the valve. And I'm going to think, how much of the outflow tract, is this jet filling. So, my outflow tract goes from about, here to here and I think this bright jet, here, is probably filling about half of that. And then I'm going to use continuous wave Doppler in an apical five-chamber view, running my cursor through the AR jet itself and I'm going to get a signal like this. And I'm going to look quite carefully at this because there is a lot
[00:01:30] of information in this. So, this is our forward flow through the valve. You can see this is occurring in systole and I'm looking at this now to see how bright it is. And then I'm going to look at the flow in diastole, which is my regurgitant jet and I'm going to compare the echo intensity, to how bright is this, compared to this. If the AR was absolutely torrential, they would be very similar. This isn't as bright and echogenic and filled in. So, I think this is probably going to be moderate aortic regurgitation. Now, if this AR jet was really sort of
[00:02:00] wispy and difficult to see and the whole wave form wasn't filled in properly, I'd be thinking that's probably mild and not because there's just not as many red blood cells in that jet, so I'm not getting such an intense signal back. So, now I've done that, I'm going to think about the pressure halftime, which is this measurement here. I'm measuring this from the peak of the aortic regurgitant jet to its minimum and then the machine is going to give me this number, here, the AR pressure halftime. So, I've done a couple of signals here and I got 244
[00:02:30] and I got 225 and I'm going to remember this number because it's going to help me in my assessment. This is a really useful view for looking for aortic regurgitation. This is a suprasternal view. We're looking at the aortic arch and the descending aorta. So, let's look over here at this color flow. Now, as you remember we're scanning from up here, so any flow towards our probe will be red, so think about that. So, flow down the descending aorta
[00:03:00] is normal, is this very bright yellowy high-velocity turbulent flow but my AR is this very sort of soft red signal coming up towards my probe. That's flow going backwards up the descending aorta and that's not normal. And I'm going to look at this really carefully now. So, I'm going to look red, red, red and what I'm doing, and it takes quite a bit of practice read to get your eye in on this, is I'm seeing how long in diastole this flow is occurring. I think it's probably most of diastole
[00:03:30] but it's quite difficult to see this. So, there are other ways to interrogate this timing of this AR jet, and this is one of them. And this is where M-mode is pretty useful really. So, we've run our M-mode cursor exactly through the part of the descending aorta we were just looking at and we get this so we've got QRS showing us that this is systole. So, this is our turbulent forward flow, down the descending aorta and then this is our regurgitant jet. And what I'm doing is I'm looking to see how long this jet goes on for. Does it go all the way
[00:04:00] to enter diastole? Well, it pretty much does, it stops about, here, doesn't it? So, it's not quite holodiastolic. You can use pulse wave Doppler similarly, here and just sample, here and again see if you get any flow in diastole and how long the flow lasts for. So, now I'm going to pull together all these pieces of information to help me make my assessment, of how much aortic regurgitation there is. I know that my pressure halftime measurement was coming out at 220–240, something like that, so that was coming in at a moderate range. When I looked in the parasternal long-axis, I thought the jet
[00:04:30] filled about half of the outflow tract. When I looked at my continuous wave Doppler, through the aortic valve and looking at the aortic regurgitant jet, I thought the regurgitant jet was sort of in the moderate range or sort of intermediate. The intensity wasn't the same as forward flow, so again, that's putting things into the moderate range. When I looked at flow in the descending aorta, I thought the regurgitant jet was almost holodiastolic but not quite. I didn't actually measure the width in the parasternal long-axis view, which I could have done
[00:05:00] right at the valve because I didn't think the images were good enough to measure that properly. But all in all, I'm going to report this as a moderate jet of aortic regurgitation. You do need to bear in mind that if the aortic regurgitation is severe, the left ventricle should be hyperdynamic, and if your ejection fraction isn't suggesting that, you need to be careful that you may have a decompensating situation. And then another thing that's really, really important to remember is the difference between acute severe aortic regurgitation and severe
[00:05:30] chronic regurgitation, you can get acute aortic regurgitation in endocarditis or in a dissection and that is a serious volume load into an uncompensated left ventricle and it can be very serious. A similar amount of chronic aortic regurgitation can be very well tolerated. So whilst you assess the aortic regurgitation similarly and make your severity assessments exactly the same, your reaction to your measurements and your findings should be different, as the acute situation is potentially much more dangerous.