This video is another in a series CIMT - Carotid Intima-Media Thickness test. It’s looking
at the carotid artery, which is right here. It also looks at the femoral artery, which
is down in the the leg -the groin area - to look, to see if you've got this process (inflammation
& atherosclerosis) going on. This black thing is a clot. It's inside an artery wall. This
artery has plaque. As you can see it's not lining the (lumen or inside). The original
plaque was here. There's more plaque forming up here. Each of these dark brown sections
and these dark brown areas are places where the immune system has attacked that plaque
and softened it. This narrow area right here is the internal lining of the artery. It broke
through and touched the blood. When it touches the blood it can form a plaque. Now let's
get back and look at this a little bit differently and this is going to be a fairly technical
video regarding a certain aspect of CIMT - again C - I - M- T - Carotid Intima Media Thickness.
It’s looking at the thickness between this intimate layer and the media layer - which
is the the muscular layer. In other words - it’s looking for the amount of plaque
that you have in your artery wall. To get to the academic point - the question is - is
the common carotid intima-media thickness the biggest part of the risk? Or is it an
average of all of the “lumps”, the discrete plaques. As you see in this article - and
you'll see in another article - I could go into a little bit more detail - with the bottom
line is - it's both. In other words, you need to look at both the average AND the average
of the the total amount in the common carotid and the average of the discrete plaques. Now
again what is that? Let's get a little bit deeper.
This is a slide from my old friends and mentors Brad Dale & Amy Doneen. This is from a publication
where they basically showed an image. I'm using it because it's got some great images.
They’ve got a great course. I have taken it multiple times. It helps you to understand
a lot of the concepts involving cardiovascular inflammation & heart attack/stroke risk. I
strongly recommend it. If you don't want to go spend a full weekend, they've got a book.
It's called BEAT THE HEART ATTACK GENE.
This image shows a good differentiation of what we mean on common IMT vs. plaque. If
you look at this structure the structure on the right. There's a long straight structure
on one side of the end. It's labeled with CIMT. That's the common intima-media thickness.
What happens with carotid intima-media thickness test, the CIMT, is this. You get an ultrasound.
So you don't get any radiation. These tests cost anywhere from a hundred, two or three
or four hundred dollars. Sometimes travel expenses are involved in it as well. So what
happens if you take a centimeter of this common carotid area. You do 70 or 80 slices whole
lot of slices in terms of looking at the distance in this dark area; which is the distance between
the intima layer of the artery and the medial layer. Why do we do that? Because that’s
where LDL - or “bad cholesterol” - gets deposited. It normally gets deposited there
as we get older. Almost all of us are born with (at least some of) it. It’s a very
small amount of that plaque. But then it grows as we get older. We call that overall plaque
burden or Common Intima Media Thickness. Over here is what we call a discrete plaque. As
you can see this is up in the area called the bulb of the carotid.
What is the bulb? It's an area where you get splitting into the internal carotid artery
and the external carotid artery. Anytime you have splitting - like a tube or a hose - you’re
going to usually get a little bit of a bulb area at the intersection. You also get turbulence
of flow. That's why you tend to see plaque -one of the most common areas to see plaque
- or a discrete large black is here in the bulb. If you take multiple averages then you
make it a larger amount. If you look at this image here, you see two different thing. You
see the CIMT. Then down in the common carotid - which is used to estimate arterial age - but
you also see what we call a discrete plaque. Anything over 1.33 ( is called a plaque).
You have different groups using different criteria - some as low as 1.0 millimeters
- some as high as 1.5 and more. Most of the groups I work with use 1.3 mm. (as saying
you've hit the cut point or a discrete plaque).
But again what we're talking about - to back up and and repeat - and simplify. We're talking
“What’s more important? The common average or the average of the highest peaks? That's
what this article is about. As you see, BOTH show additive value. So you can't really use
just one or the other. You need to use both. I'll go a little bit more into detail on it.
The last article this one was in atherosclerosis in August of 2017. I’ll go into a little
more detail on this one.
This was in the Journal Atherosclerosis & Thrombosis back in 2011. They basically were saying,
“ look it's unclear whether Common imt or Mean Maximum cimt should be used. Again when
you say mean maximum you're saying,”okay this is a maximum level. You have multiples
of the discrete plaques. Let's get an average - an average of the maximum levels. In other
words - an average of, “how many discrete plaques do you have and how big are they?”
At that time, they felt,” it's unclear so let's take a look directly compared both measurements.
They did lit ( science literature), a review up to 2008 at that point. 15 trials were reviewed.
They looked at Common IMT and mean maximum cimt. They compared both both of those. Then
the studies that they used needed to have outcome measures: heart attack,stroke - that
sort of thing to say, “okay, did this actually predict reality?”
And here’s what they found. Reported reproducibility was high for both measurements although a
direct comparison was not plausible. They went on to say, “based on looking at that
maybe the mean maximum cimt is the primary outcome. But you know what - we can go back
and predict common IMT. ‘
The science has progressed. You go back to this one - article in Atherosclerosis- the
2017 article. It's becoming clearer and clearer - you really need both. You need to get the
average of those large discrete plaques. AND you need to get your average age.
Many of you have seen my video where I talked about my own carotid intima-media thickness
test. This is it. When you look down at the my carotid age (or the common age or the common
IMT down in my common carotid artery), you see that my age prediction is 52 even though
I'm 61. That’s actually old news for me. We'll talk about my older one in a minute
and the progression that I had ( prior to this CIMT). The average CC at common carotid
artery mean IMT and the average CCA Max region. Again these were the things that we’re comparing.
My common carotid artery IMT was .68 my CCA Max region was .81. So again, I did have a
couple of discrete plaques as you see down here. Both of those numbers are important
to looking at risk ( of a heart attack or stroke). When you go back and you look at
my video talking about my decrease in cimt age, it was based on this cimt - which was
done with another company. This is one of the reasons why I recommend CardioRisk. I
had this from another company back in February 2015, October 2015, and September 2016. You
saw a steady decline in my arterial age from 73 predicted arterial age (this light blue
dot) in February 2015 - down to 52 in September of 2016. And again, the one I showed you a
few minutes ago was with Todd's group (CardioRisk) and an about age 52. But I still have that
risk associated with the Mean Max regions (or the discrete plaques).
Again, this all gets little bit technical. It gets frustrating - in terms of trying to
understand it. But let me go back up and simplify again. The bottom line is - there different
techniques of looking at this. One is to look at your arterial age. The other is to look
at the average of your plaques, your discrete plaques. The other bottom line is- it's clear
- you need to use both: the Mean Common AND the Mean Maximum.
So - get a CIMT. If you have to use a company that's not giving you both pieces of information
- ( still) do that - because what's clear is - the CIMT is helpful. Despite what you
heard with some of the confusion that John had on his recent CIMT follow - up, there
is nothing like getting a wake up call with CIMT.
Let me show you a graph in terms of that first wake up call that happened to me. Again I’m
a preventive medicine doc. I’d been doing preventive medicine for decades. I’d stayed
thin. I’d managed my risk factors. I expected to do a Victory lap after my first CIMT. As
you could see, I had 73 year old arteries. That was a major wake-up call. I was one of
these people that you see on the right side of this of this graph. (This graph … there
are several different attributions to make here. It's an old study done in 2001. It was
the definitive study for CIMT. You see Grace Clinic on here. You see Bale Doneen. Brad
Bale was at the Grace Clinic in Texas. He’s used this image several times. It’s a great
image. That’s why I’m using it as well. - for other attributions to Brad & Amy, see
my other videos.) ( This is the CAFES CAVE study). Basically, on the CAFES - CAVE study,
you saw several things. Number one - they took low risk individuals. They did the Carotid
intima-media thickness test CIMT. What did they find? Despite having low risk 40% of
these folks actually had plaque on CIMT. I was one of those people that thought I had
little to no risk factors. Yet you go and you look. You do this ultrasound (CIMT). You
find you may have a lot more than you thought. And this is a lot more common than you thought.
It's sort of like prediabetes, or insulin resistance. The UCLA study that John covered
in his video. It's saying half of us have insulin resistance (or prediabetes - actually
over half of us >30 years old) .
There is also another dot to connect there. What's the most common cause of this kind
of risk? By far it's Insulin resistance. So I got a major wake-up call. There is a lot
more risk out there. All you have to do is take a look at your arteries. I did and I
got a major wake-up call.
Now - here are a couple of other images to put things into perspective. These are cross
sections of arteries. The red layer there is the muscle layer - the media layer. The
inner lining is the intima layer. The grey stuff in between is plaque. All this on the
left hand side ( the left image) is stable. It's a lot of plaque. You don't have hot liquid
plaque in there. But the point to this one is - on the top side ( of the left image)
you have a huge IMT - Intima Media Thickness. On the bottom you have very little visible.
So there's a lot of variation in intima-media thickness. That's something to remember as
you hear stories like the one from John - where I said I wasn't quite sure how to interpret
it.
Well again - it's clearly worth taking a look. Don't guess - test! I realize there are things
that can complicate this. For example, the thing we talked about today - getting an overall
vs average of your peaks - of your discrete plaques. What we want to avoid is what you
see on the middle and right hand picture ( the liquid area of plaque). Our immune system
is attacking the plaque, making it liquid. That liquid going out - touching the blood
in the artery - forming a clot going to your heart (or your brain) - causing a heart attack
( or stroke).
One last image and then I'll finish it up. We keep talking about plaque and inflamed
back. This is a microscopic image. What you see is that we deposit LDL (or bad cholesterol
). Let me orient you. In this slide this middle layer - a one cell layer - is the intima - or
the endothelium of the artery. This top area - where you have these red donut looking things
floating around - that's the bloodstream. Down at the bottom you have this scaly-looking
thing. That’s the media layer. That's the muscle layer of the artery. If you go from
left to right on this slide - you get more and more deposit of LDL - and more and more
attack of that LDL - that plaque - by the immune system. Over on the right you have
what's called a hot liquid plaque. Your immune system has attacked that plaque, trying to
digest it. Again you do want to get rid of plaque in your artery wall. But if your immune
system attacks it - and it releases into the bloodstream - you get what's called a thrombus
( or a clot) - which again takes you back to an unpleasant ending.
Thank you very much. As many of my videos have been, this has been a long one. But we
wanted to get into some details about CIMT. We will be covering more aspects of it in
other videos. We also wanted to cover the quality between CIMT providers. One of the
key things is to note that they do both: Mean Max (meaning looking at the average of all
of the discrete plaques and how big they are); and Arterial Age.
Thank you again.