Assessing Cardiac Valves - The Mitral Valve

18 minutes
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In this lecture, you'll learn several methods to assess the mitral valve for stenosis and regurgitation and grade them, as well as recognize some of the most common pathologies affecting the valve. We'll be discussing valve area assessment using planimetry and pressure half time (PHT), pressure gradient calculation, as well as looking at examples of mild, moderate, and severe mitral regurgitation (MR).


Welcome back. So now we've learned how to measure Lv and RV size and function. It's now time to learn to assess cardiac valves. We'll start with the mitral valve. mitral valve separates the left atrium and ventricle and is visible in many of the standard views. The first step of assessing the mitral valve is to examine the appearance of the valve into the normal valve should look like this.

This is the anterior leaflet and this is the posterior leaflet. The leaflets should be thin, thinner than five millimeters and we can measure that using the caliper after freezing the image. They should also have free mobility on the ventricular side but should not cross the plane of the mitral annulus on the HTML side, as represented by this line drawn by caliper and a pair of stern along axis. If any portion of the leaflets cross this line, this is called mitral valve prolapse. The leaflets should also meet at the tips Viewing System. This is called normal lactation.

And abnormal mitral valve can be due to rheumatic heart disease degenerative valvular heart disease, also Cause clearer calcific of your heart disease or mitral valve prolapse, among others. This here is an example of a rheumatic mitral valve in pair of sternal long axis view. As you can see, the leaflets are obviously thickened and the Enter valve leaflet has restricted mobility at the tip leading to dooming of the anterior mouth leaflet consistently, which is actually characteristic of rheumatic heart disease. The posterior leaflet motion is also restricted, it's virtually not moving at all. It's also notable how the leaflets don't exactly meet at the tips but rather the tip of one leaflet needs the side of one leaflet. This is called tip to side.

Now co optation. Notice also that the QWERTY 10 beanie and the papillary muscles, what we call the sub valvular apparatus are thickened. This is another view of rheumatic mitral valve. In this case the patient is in atrial fibrillation. You can see how the heart rate is rapid and irregular. There's also a large atrial thrombus here because of the atrial fibrillation.

If we take a still image of this sequence, you'll see also again the systolic darkening of the interior mitral valve leaflet is a characteristic pattern that we call the hockey stick deformation because the leaflet kind of resembles a hockey stick. This is an example of a valve with degenerative valvular heart disease or scleral calcific valvular heart disease usually happens with age, but in the case of this patient, it's he's this patient is a chronic kidney disease patient and these patients scleral calcific. damage to the valves happens early on because of calcium deposition in in the tissues, especially the valves. So you can again see how the leaflets are thinking and calcified as evidenced by this big chunk of calcium on the belt. Motion is also severely restricted and this valve is actually severely demonic. This is an example of a patient with mitral valve prolapse.

Let's let's take a still image of this. Remember the annular plane line that we discussed before. This is again drawn from the basis of the two leaflets. And it's easy to see that the leaflets cross and prolapse beyond this line back into the left atrium. This is a normal valve again, but in a different view, the power struggle short axis view at the mitral valve level. And you can see how the two leaflets are moving well and how the valve area is quite normal.

Compared with this, this is rheumatic mitral valve with mitral stenosis, and you can see how the commissioners of the valves are fused at the periphery. Leading to reduced vowel area and and the fish mouth appearance as we call it of the mitral valve. The next set of assessing the mitral valve is to look at it using color Doppler. This is again a normal valve in a typical for chamber view. And it's also easy to see how both leaflets are mobile and pliable. Compared with this rheumatic mitral valve, leaflet motions is restricted and leaflets are thickened.

This is the 2d appearance of the valve. The next step is to use color Doppler to assess what flow across the valve. This is an example of color Doppler over a normal mitral valve in a vehicle for chamber view. There's only a very trivial jet of mitral regurgitation, which is acceptable and diastolic flow is not Compare it with this. In diastole the there is a flame shaped jet, which indicates turbulent blood flow. And this this appearance is commonly observed in patients with mitral stenosis.

You can see the aliasing which means all these millions of colors, the green and yellow and red and this means turbulent blood flow. This is another color shot of the mitral valve showing an abnormal jet of blood flow from the Lv back into the left atrium. This is called mitral regurgitation or mitral incontinence for mitral insufficiency. So now that we've learned to spot mitral stenosis and mitral regurgitation regurgitation, the next step is to determine the grade or the severity of stenosis or regurgitation. Let's start with regurgitation. This is an example of a normal Val showing trivial mitral regurgitation.

And as we said, trivial Mr is acceptable and is normal. There it is. This is an example of mild Mr. There are several criteria that we use to judge the severity of regurgitation. And there are even ways to estimate the volume of the regurgitated blood, but we're gonna keep it simple. Some simple criteria are jet length, Jet area compared to left atrial area and V net contract.

As we said, this is an example of mild Mr. Let's take a still photo that you do that by freezing the image and using the trackball if necessary to track to the shot where the regurgitation is at its most jet area, Jet length too small, and jet area is less than 20% of the left atrial area. You can just judge that by look Use the area feature like we did an RV fractional error change via contract means measuring the diameter of the narrowest part of the jet or as we call it the neck of the jet. And we measure it using caliper after freezing the image of course, and tracking to the part where the neck of the jet is most visible. This is the V neck track to hear in this case and mild Mr. Has it been a contract of less than three millimeters.

This is an example of modern Mr. Again, let's take a still image. Jet length is longer, and the jet fills more than 20% of the left atrium, left atrial area. And, and if we measure the VENA contractor, measure right here at the tips of the leaflet it will lie between 0.3 and point six millimeters in this case 4.5 minutes This is an example of severe Mr. Let's take a still image of that severe Mr has a much longer jet length usually the reader area or the jet area is more than 40% of the left atrial area. And the vena contract when measured is 0.7 millimeters or higher. point nine in this case. Other clues indicating the presence of severe Mr swirling of blood in the left atrium, as you can see in this case, and reflects the blood into the pulmonary veins visible down here and epical for chamber view, you can you can also make sure using pulse wave Doppler placed at the mouth of a pulmonary vein and presence of flow below the baseline system it means regurgitation into the pulmonary veins, which is consistent with severe Mr. Another important sign in severe Mr is a dilated l Although this happens in long standing Mr and not in acute cases, there are a special type of Mr. That I'd like to know that I'd like you to know about, which is called functional MRI.

Functional MRI. This is an example of functional MRI functional MRI is Mr. That happens in the absence of any valid pathology, but is due to marked Lv dilatation, which deforms the mitral annulus or pulls on the Cordy 10 deenie interfering with properly closure. This is an example of functional MRI as he said, and you can see how the valve leaflets look normal. Okay, so what does it mean for you when your patient has severe Mr. Well, Mr increases as systemic blood pressure increases, because in that case, there is more resistance for flow, and the blood takes the easy way out back into the atrium and through that to the pulmonary circulation. So in patients with severe Mr. You need to tightly control blood pressure at target value is even lower than usual. And you need to use vasodilators to increase forward flow.

Okay, so that was regurgitation. Now let's move on to mitral stenosis. stenosis means a narrow valve area which causes obstruction to blood flow and high pressure gradient across the valve. The first clue to mitral stenosis is a small opening on 2d as we've just seen. The next step is to measure the pressure gradients and the valve area. pressure gradients across the mitral valve are measured using continuous wave Doppler in the typical for chamber view.

Let's position the cursor now cross the mitral valve opening and press CW press freeze now. And this is an example of a normal continuous wave Doppler trace on the mitral valve. This is flow above the baseline so it's flow towards the pro that is safe from the LA to the Lv, which is normal direction of workflow across the mitral valve. In most what phase of the cardiac cycle does that happen? Yep, diastolic when ventricular filling occurs. To measure the pressure gradient, bring up the measurement pane, select mitral valve, go to mitral valve bti.

Sometimes it's going to be called mitral valve trace depending on your machine select an envelope which is clear enough and start out at the beginning of this envelope. Press the left mouse button and trace plays like this. This is called the E wave and this little wave is called the a wave for each interaction, okay and press the end. So, the V max is called the maximum velocity. The V mean is the mean velocity. V max PG is the peak gradient and the mean PG is the mean pressure gradient across the mitral valve VTi is called the velocity time integral just forget about that for now, let's just focus on the mean gradient.

As you guess the main gradient is the the average overall gradient for the whole envelope, while the the the maximum or key gradient is the, the topmost point in the envelope. A normal ingredient is below two millimeters of mercury. I mean grading above 10 millimeters of mercury is consistent with severe mitral stenosis agreement below five is mild stenosis and in between is moderate. There's one important thing that you have to keep in mind though, in the case of atrial fibrillation, which very often coexists with mitral stenosis being actually secondary to it. The envelope will be variable in size like this with a variant with larger ones occurring after longer pauses. This is an example of continuous wave mitral inflow in an atrial fibrillation patient.

Notice how the envelope is single peak As opposed to the normal double peak due to the loss of the atrial kick, there's just an E wave, there is no a wave. And now, which of these do we measure? The ideal answer is all of the above, well, actually five of them, you should measure five beats and average them avoiding outliers. You don't need to do all that though the valve is obviously an astronomic. The next way to quantify stenosis is to calculate the valve there. There are several methods of doing that and we will be discussing two of them.

You should always do both to make sure the first method is valve planetree. And this is the standard and usually the most accepted method. Remember that pair sternal short access mitral valve level view that pneumatic mitral valve with the fish mouth appearance, that's the view used to measure valve area. Let me just point out that again, we don't measure valve area unless the valve looks suspicious of beings to notice the valve with the clearly well opening leaflets in 2d doesn't need its area measure. Anyway, let's get back to that view. What you want to do is keep tilting the plate drove up and down until you can see the narrowest aperture.

Remember that you're imaging a 3d structure and a synoptic mitral valve looks like a cone, which you're trying to cut in cross section. So you keep looking until you find a cut on the apex of that cone. So if, as you see in this example, the cut is away from the apex and the mitral valve area will look deceivingly Normal. If we tilt the probe to move the plane forwards a little bit, we get a little closer to the apex, we're still not at the apex and the valve area will still look higher than real area. This is the correct plane at which we're supposed to cut the mitral valve and this is the cut that will give us the real mitral valve area. Anyway, let's get back to that view.

Well you want to do is keep tilting the probe up and down until you can see the narrowest departure freeze the image, use the trackball Track back to the valve when it's accidentally open in this view Okay, so this wouldn't be it. Now bring up the analysis or measurement panel go to valves, mitral valve area we use that in the ER you fractional area change if you remember. Now start click the left mouse button now or the left trackball on anywhere along the opening valve and start tracing valve area. Trying to keep to the border as best as you can, and going into all the nooks and crannies so okay there we have it miles out area is four centimeters square. Normal mitral valve area ranges from four centimeter square to six centimeter square valve error area below one centimeter square is consistent with severe mitral stenosis and area above 1.5 centimeter is mild gnosis and anything in between is monitoring.

Another way to estimate mitral valve area is pressure halftime. Let's go back to that mitral valve continuous wave Doppler trace we saved and the same one we used to estimate the pressure gradients bring up the measurements pain again, go to mitral valve, mitral valve pressure halftime. Now, as usual select through cut envelope, mark the top the left trifle button and then you have this other cursor connected to the first verse of the line and you need to align that with the edge of the slope until Reach the baseline and mark it again. And you have the pressure half time 50 millisecond milliseconds and the mitral valve area estimated according to this pressure halftime it's 4.4 centimeter square. And that is consistent with what we measured with planimetric. The machine will perform this calculation for you and give you the estimated value of four.

And this is pretty close to the value we had we got by finding entries. So that means we did a good job, you should always make sure your data fits together. If it doesn't make sense. If for example, the gradients are really high, but planetree gives a normal value area and you probably did it wrong, go back and find the narrowest part of the cone and measure it again. So now your patient has severe Ms. What does that mean for you? It means that you should keep the heart rate down because rapid heart rates means shorter diastolic and less time available fulfilling, which is already reduced.

It also means that your patient could easily develop pulmonary congestion, in which case you're probably going to need to use diuretics. I know this lecture was a little dense feel free to go over it one more time if you like and I'll see you in the next lecture assessment of the aortic valve.

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