CIMT: Not Perfect, But Better Than Stress Test or Calcium Score


So the vast majority of CIMTs that
patients bring in to me are really bad. Though I think the absolute worst one
was last week. A patient brought a CIMT where his local radiologist told him, “Yes,
this is a CIMT.” It wasn’t even in the neck. It was a lower extremity ultrasound,
so it wasn’t a media thickness test and it wasn’t carotid. It was awful. So Michelle and I are continuing
to work on various ways to get you guys access to better CIMT. As I’ve said,
I’ve worked with several providers in the country.
Todd’s group is by far the best. He’s developed national access. There are a
couple of others. I still use a guy, a neurologist named Fred Callahan in
Nashville, Tennessee, And there’s a group in LA that occasionally does a good job.
Again, we’re going to be coming out to LA in September to provide you what we know
is high quality CIMT. But why all the problems with the quality of CIMT?
That’s actually what this video is gonna be about. I published a video that
covered this a few months ago but a couple of things happened inadvertently.
That video got linked to another one which was totally unrelated. We’re
looking to see if we can edit that out. It got a thousand views so you may have
seen some of this already. If you have and it’s repeat for you, just be warned
and just wait for the next video. But I think one of the problems is it made it
a thirty minute video when it’s really only five to ten minutes. So I’m gonna do
a quick video for folks that haven’t seen it and folks that were put off by
the inappropriate little long length. Anyway, so what is the purpose, what’s the
goal for a CIMT? It’s to help patients visualize what’s going on in their
arteries and again I won’t go through the details on this. But you see going
from left to right you’re getting more and more and more increase of the plaque
process in your arteries. This doesn’t happen in the arteries of the neck and
head without happening everywhere else. So I still get patients comment to say,
“Well, that’s just in your neck. That’s not in the heart.” Your arteries are your
arteries. They pump the same blood. I mean every minute blood goes through can make
the trip throughout the whole body. So what’s going on in one bed… artery bed
is in another. So what are the problems?
Actually, there are more than one problem with CIMT. The biggest one is
technologists technique and it has to do with what I call the problem of
“perspective.” I’ll get what does that mean. I’ll get to that in just a minute.
There are other issues as well. Standardization of reporting in the
research has led to a bunch of really bad CIMT studies. Getting into the research, when you look at the groups that do it well…and again Tod’s
is not the only group, is the only one that provides national access.
There’s several academic groups and a couple of others that I’ve mentioned
that do provide local access where you can get a good CIMT. And when you get a
good CIMT, it’s better than anything else because of the problems with the
standardization of reporting in the literature. The standards committees
looked at the literature of a science and said, “This doesn’t work. That’s not
standardizable.” Well, it is again in the right hands. Now let’s go back and
talk for a minute about this issue with the problem of perspective. Let me
actually go to a picture and you may recognize this picture. If you saw… if
you’re one of those thousand people that saw the original video a few months
ago, this is creating a… this is a photographer obviously creating an
optical illusion. It looks like the boys are as big as the Eiffel Tower. They’re
not because they are just way way closer to the camera. So how does that what does
that have to do with plaque? We’ll go to that in just a sec. But here’s the thing
to remember. Plaque is not uniform around the circumference of the artery wall.
Some of its thin, some of it’s I’ve got thinks on of it, some of it’s thick. So
again, perspective matters. Now as you begin to look at these, you can get some
again perspective on this issue. These are cross-sections of arteries. The
red part is the muscular layer, the media. The intima is this tiny, thin layer
here. But then everything in between is the
is plaque. And as you see here, this is liquid plaque. Now this is fairly
uniform. But still, even this one, if you took a cross-section through here, if
you’re shining the ultrasound waves through here, you’re gonna… you get the
back end… the opposite…. the opposite side of the artery that you’re coming in from.
So if the technologist is coming through here, they’re going to get this thickness.
On the other hand, obviously, if they’re coming through if they were coming
through here, they’re gonna get a thicker amount. Now you don’t really have that
much ability to mess this up but you do have some and it is significant look
at this artery for example huge amounts of plaque on this side. So for example, if
the wand came in through here, you’d get this much plaque. If it came in
through here, you get a much bigger amount. And obviously, if it came in
through here, you might get much less or nothing at all.
And yes, you will routinely see plaques that have been missed again. Even with
the problems with CIMT, if you get a good one, a good high-quality CIMT, it
tells you so much more than any other measure that we have. This is just again
another look at a real live artery and we’ll go in and look at some others in
just a second. As you see, this was soft plaque that’s no longer soft anymore. It
has broken through the intima layer and a clot has formed, this black thing.
The majority of that clot broke off and went on to cause the heart attack which
killed this patient. But again, as you can see here, this is the media, this clear
white looking area, that’s the intima. And then so that’s the plaque, so much less
plaque. If you had come in from that side, much more plaque. If you came in from
over here, and again more plaque. If you came in from this perspective, another
artery which again shows a significant variation. And again the potential ways
to miss plaque if you’re coming in from a HD IMT. So again, as you might say,
“Look, this is awful. This is terrible.” Let’s get back and think about
the alternatives. The most commonly used alternative is a stress test. It doesn’t
see anything at all unless there’s over 50% occlusion and it has all it has up
to 30% false positives over that many false negatives because 68% of heart
attacks occur in people that have less than 50% occlusion. So by definition,
those people are going to have a false negative stress test. We say, “Well, let’s
go to get a calcium score.” As many viewers have pointed out, calcium score
measures only calcium. And plaque like this, that’s soft, that is likely to
rupture and cause a heart attack, doesn’t have calcium in it. So that would not
show at all on a coronary calcium score. Now to get a
little bit more perspective, here’s the model of a carotid artery and obviously
in a dummy and you can begin to get a little bit more vision and as I’m using
obviously and talking about maybe my if my hand were the one the ultrasound wand.
I’ve trained some in doing these. I’m not very good at doing them, but as you can
see, you’ve got to know exactly which level to get the carotid bulb. You’ve got
to know whether to come in from this side versus this side. And again, that is
a significant variation when you begin to think about the variation that you
can see in those arteries. Bottom line is it is not easy to get a good picture of
plaque. You’ve got moving arteries and that’s a problem with things like CT (computed tomography angiogram). It’s also a problem with other items as well.
You’ve got moving arteries. You’ve got plaque that is not uniform in terms of
its coverage around the circumference of the artery. You’ve got the fact that
arteries in the chest are behind bones. And you’ve got the fact that blood flow
measuring blood flow like using something like a stress test doesn’t
work because you get plenty of blood flow even though
they have significant amount of plaque and plaque that can cause a heart attack
and stroke. So hopefully, that helps you get some more perspective on CIMT the
problems of CIMT, and how those compared to other methods of understanding and
measuring screening for plaque. If you’ve made it this far, thank you very much for
your interest. This is Ford Brewer. I started off my career as an ER doc. And that can
be frustrating because most of the things bringing patients into the ER can
and should be prevented, like heart attack and stroke. So I went to John
Hopkins for training in prevention. Did well, ended up running the program,
trained dozens of docs there, and have trained hundreds and even over a
thousand doctors since then in preventing disease. What’s even more
important is I’ve helped thousands of patients prevent heart attack and stroke
rather than waiting for the devastation and hoping for a cure.

7 thoughts on “CIMT: Not Perfect, But Better Than Stress Test or Calcium Score

  1. Once again- great video! I have sat through several CIMTs (hubby’s). It is very similar to an ultrasound that pregnant women get- but it focuses on the carotid artery in the neck rather than the womb. You are right about the technician being the key!

    Those arteries can go from 70% to 90% pretty quickly.

    Folks, please don’t trivialize plack in the carotid artery! The blood flow & oxygen to the brain is a real issue- and it really alters behavior. I won’t bore people with the details, but when the brain doesn’t get blood and oxygen, it can cause long term damage to your loved one. It is devastating.

  2. I get a yearly "CIMT" at a local health fair where they use a doppler measurement for velocity. Doesn't this account for the various plaque distribution possibilities when the results show faster flow through more restricted arteries? In the hands of an average technician, wouldn't this be a better test?

  3. I don't agree that CIMT is really better than CAC. CIMT tests cost more, are much less available, and they provide less information specifically about the coronary arteries. CAC tests provide not only a calcium score but a breakdown on individual coronary arteries. When I took my CAC it turned out that the results were very different depending on which coronary arteries were examined. Some patients have the calcium deposits distributed more or less evenly. Others like me have it mainly in certain places.

  4. I had a CIMT from Cardiorisk at the September event in Anaheim. Unfortunately I still haven’t received the results. 🙁

  5. dr, all very interesting. could you not make a video showing how all these tests are done and the expense of each test (in yr area) kraft insulin, cimt, cac…

  6. dr, how does this plaque start out and how do we prevent it and what is responsible for this soft plaque, is it carb food and insuline always high causing insuline resistance and inflamtion?

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