Welcome back to lecture nine of our course. So I think the track has been valid and pulmonary artery pressure. As you probably guessed, assessing the tricuspid valve is similar to the thing the mitral valve only much simpler in our case. Let's start with the cuspid stenosis this time, since there's not much to say about it tricuspid snows is quite rare, and it's unlikely you'll come across it. This is an example of a synthetic tricuspid valve. You can see how the leaflets don't open all the way.
When you see a suspicious tricuspid valve. All you have to do is measure gradients using continuous wave Doppler. Let's go back live to a normal valve. This is a normal tricuspid valve but process the same for an abnormal Val. Similar to the mitral valve, open up the analysis from two valves, tricuspid valve, and tricuspid valve trace our tricuspid valve VTi with the cursor to the start of an envelope and trace the same way you would mitral valve. There are no rates of stenosis, there's just significance gnosis or not an ingredient, about five millimeters of mercury is significant stenosis.
Now that that's out of the way, let's move on to regurgitation. Again, it's exactly like my old regurgitation, Jet length jet area, and Vina contract with the same cutoff values. This here is an example of severe tr. Similarly, regurgitation that reaches all the way into the hepatic vein strongly favors severe tr. This is a subclass of the IVC view and this mark with an arrow is the hepatic vein And regurgitation reaching all the way into this compact vein favor severe tr. You can also check using pulse wave Doppler and flow above the baseline means reflux of blood into the hypnotic vein consistent with severe tr.
Now the other value of assessing tr is that we use it to estimate RV systolic pressure, which in the absence of pulmonary stenosis is equal to the pulmonary artery systolic pressure and important hemodynamic parameter. I'm not going to show you how to calculate our VSP. Let's go to the atypical for chamber you bring up color Doppler. The first step in measuring our VSP is obtaining continuous wave Doppler across tricuspid rigored. Almost every tricuspid valve has some trivial degree of tricuspid regurgitation and that's what we use to estimate pulmonary artery pressure. There it is.
So So fleeting yet let me just place the cursor on it and fire up CW and increase the Doppler gain a little bit so that the the envelope is well visualized. And now all you have to do is simply to find the TR V max on the measurement pane for the tricuspid valve and move the cursor to the lowermost edge of the envelope and press now you have the V max and you have the maximum peak gradient, which is 19 millimeters of mercury. And now we're missing to calculate the right ventricular systolic pressure or the pulmonary artery systolic pressure is the right atrial pressure. We don't measure the rip using echo. You can you can measure it using a central venous line because it's basically the same as the CVP. However, we can estimate it using echo by looking at the inferior ventilation In the sub coastal IVC view, let's go there.
Now. This is a coastal view. And if I rotate the probe, I have the inferior vena cava view. That's Yeah, this is the inferior vena cava. Well, well visible in this case. And inferior vena cava supposed to have phasic changes with respiration.
It's supposed to collapse with inspiration, and so up on expiration, because of the diaphragmatic movements, it should measure less than 1.5 millimeters in diameter, I'm going to freeze the image and use the caliper to measure it usually one centimeter distal to its origin. And it's about 1.37, which is normal. So now that we know that the IVC diameter is normal, it's time to explore phasic changes with the respiration. On freeze the image we do that using m mode placed at the mouth of the IBC. And as you see, the trace will show us the IBC. as it expands and collapses with respiration, we freeze the image track back to a representative section and then we can use caliper to measure the IVC diameter at the narrowest and widest points.
Okay, so the narrowest point was about one centimeter let's go to the widest point. This is an inspiration measure that is about 1.8 centimeters. The variation should be more than 50% normally, but then again, I should have instructed the patient to take a deep breath. So we'll go ahead and consider that normal. If both the IVC diameter and respiratory variation are normal, then the rip estimated RP ranges from zero to five millimeters of mercury if the IVC is dilated, Over 1.5 centimeters but less than 2.5 centimeters and respiratory variation is normal greater than 50% then estimated RP is five to 10 millimeters of mercury. If the IVC diameter ranges from 1.5 to 2.5, but, respiratory variation is subnormal then estimated RP is 10 to 15 millimeters of mercury, if the accuracy is above 2.5 centimeters and respiratory variation is subnormal then our AP is 15 to 20.
If the IVC diameter is above 2.5 and there is no change at all, with inspiration, then estimated RP is in excess of 20 millimeters of mercury. Now that we have the RFP we add it to the P gradient obtained by continuous wave Doppler of tricuspid regurge and what we get is the RV SP The pulmonary artery systolic pressure, if you remember we we obtained a p gradient of about 19 millimeters of mercury, so add zero to five. So our gradient is 19 to 24 millimeters of mercury. And that is normal because normal pulmonary artery systolic pressure is 15 to 25 millimeters of mercury. Elevated pulmonary artery systolic pressure above 60 millimeters of mercury is severe pulmonary hypertension below 40 is mild and in between is moderate. That's all for this lecture.
We'll see you in the next lecture assessing the pulmonary valve