0:00

This patient had a renal transplant and now is elevated creatinine

0:03

and we were asked to performate ultrasound to

0:06

evaluate the Theology of that and so we can look at this transplant

0:09

and grayscale. Imaging looks pretty good the right lower quadrant

0:12

metrics by 10.9 centimeters, no mass is no collections.

0:15

We're looking at the national transverse plane doing color Imaging

0:18

to ensure there's flow throughout the transplanted kidney. There's

0:21

venous flow over here as we're interrogating the vessels inside

0:24

the kidney itself.

0:26

Let's look what happens. We interrogate some of the arteries here lower

0:29

pole segmental artery. Now, let's actually looks

0:32

a little bit different than some of the waveforms that we've seen

0:35

in some of the other cases. Normally these renal

0:38

artists should have nice sharp systolic up

0:41

strokes and flow throughout diastole. Now this

0:44

instance, we do have diastolic flow, but that Sharps systolic

0:47

upstroke is missing and instead it's sort of an angle

0:50

over here. And so that itself is

0:53

a little bit worse and you can see how it's slanted over

0:56

here.

0:57

And also when we look at the peak systolic velocity, it's a

1:00

little bit lower than what we would expect right and some

1:03

of the other ones we've seen and we never quite got as low as 15

1:06

centimeters per second. And so we see that

1:09

in the lower pole segmental artery if we look at the interloper artery,

1:12

it's more pronounced we can see that it's

1:15

very very slanted and look at the peak systolic velocity

1:18

here nine point three centimeters per

1:21

second. And so this sort of waveform where there

1:24

is diminished Peak systolic velocity and

1:27

a long elevated time

1:30

to reach the peak systolic velocities known as a Tardis parvis

1:33

waveform and there's certain criteria

1:36

that we can use in terms of the time to reach Peak systolic

1:39

velocity. Generally if it's about 70 milliseconds, it's going

1:42

to be Tardis parvis. It's going to be delayed up stroke oftentimes

1:45

we can be subjective about it, but there are

1:48

objective criteria for that. And so what this means when

1:51

we look at these vessels and we see this waveform within the

1:54

intraprenchymal arteries it tells us

1:57

somewhere

1:58

proximal to where we are interrogating in this

2:01

renal transplant. There is some narrowing of

2:04

the renal artery renal arteries stenosis somewhere.

2:07

Right. So when we have a renal arteries stenosis the end result

2:10

of that.

2:11

Within the renal Transit is going to be a waveform that

2:14

looks like this.

2:15

And so here we are integrating the lower pole region. When we

2:18

interrogate the upper pole region. We can see similar waveforms of

2:21

that slanted appearance due to

2:24

elevated time to reach the peak systolic velocity the peak

2:27

systolic philosophy itself is quite diminished at 12. The interlobal

2:31

arteries also looks similar. So throughout the renal transplant. We

2:34

have Tardis parvis waveforms that tells us it's somewhere along the

2:37

course of the renal artery that's in

2:40

anastomosis with the external iliac artery. There's some degree

2:43

of narrowing and so our next step is to really figure out where that narrowing is.

2:47

And so we then start looking at the main

2:50

renal artery itself.

2:52

We can see at the hilum. It's quite elevated velocities of

2:55

300. But that's again just one time point we need to look at everything else.

2:59

Look at the mid portion of that renal artery 402 quite

3:02

elevated velocities in that location

3:05

and we can also see some aliasing which means

3:08

that there's just turbulent flow in that region find that

3:11

suggest that there is some degree renal arteries

3:14

stenosis and close proximity or within that location itself.

3:18

The external iliac artery proximal to all

3:21

these findings essentially the inflow velocities are at 94

3:24

and so we're really going from a velocity

3:27

of about 94.

3:29

To at least at the mid portion 408 so

3:33

almost a four-fold change. We'll find the anastomosis velocity

3:36

itself in a little bit but that itself tells

3:39

us there's some degree of renal arteries stenosis in

3:42

this patient that we have to interrogate as we

3:45

find the anast most we can see that an ass to most is all

3:48

the way up at 400. And so these constellation of

3:51

findings are compatible through your monitors stenosis. It's

3:54

important to remember what this looks like because this is the most common

3:57

vascular complication in real transplants, which

4:00

you're really looking for is a bunch of things within the

4:03

renal transplant itself. You're looking for these Tardis parvis

4:06

waveforms and then when you interrogate the renal artery itself,

4:09

you potentially can see a side of narrow and grayscale imaging

4:12

but what you're really going to be looking for is this aliasing as

4:15

well as a jump and velocities of about 3.5

4:18

times from the inflow

4:21

to the area stenosis to suggest that that area

4:24

is narrowed and physiologically significant narrowing

4:27

now remember in the

4:29

Immediate postoperative period post-operative Day

4:32

Zero for example you sometimes can see elevated velocities this high

4:35

but that's just due to edema causing narrowing in

4:38

that location and that itself usually doesn't cause

4:41

those Tardis Tardis waveforms more distally so an

4:44

immediate postoperative period you may expect these high velocities and those

4:47

will subside as the edema goes away. But if you're

4:50

a couple of days out from the transplanting you're seeing these findings

4:53

or that Tardis harvest waveforms in the kidney have to

4:56

be worried about renal arteries stenosis.