Okay, let’s go on to talk about Class III.
Now, Class III type of Pulmonary Hypertension
and all of these, ladies and gentlemen, you
really must know in detail. Okay. So, I am
not wasting your time. With Class III, it
is actual lung disease that took place primarily.
In Type 1, the majority of a more familial,
but then you also had drugs and other habits
or diseases, but then here, if it’s Type
3, it is primary lung parenchymal disease
of all of which COPD would be the most common.
Okay. Now, along with COPD, say that your
patient is suffering from hypoxia, now, what’s
the state of your pulmonary blood vessels?
It is called, remember, one of the big exceptions,
when there is hypoxia in which blood vessels
constrict would be hypoxic vasoconstriction
and nowadays, in current day practice, your
patients very well might be obese and
so, therefore, you are thinking about obstructive
sleep apnea, and then, of course, high-altitude
residence. Here once again, because of low
barometric pressure, thus resulting in decreased
FiO2, you find your patient having hypoxic
vasoconstriction. That’s Class III.
Then we go into Class IV. Class IV, if it
helps you any further, you need
to remember, this is a thromboembolic
disease causing a Pulmonary Hypertension.
So, we had a discussion about PE and all the
different ways in which you might then develop
a PE. The most common of which would be your
DVT, right? But, keep in mind though that
you can also have embolization from different
sources. We talked about the amniotic fluid
emboli, we talked about the gas emboli, the
fat emboli, all depending as to the situation.
Anyhow, so there is a thromboembolic disorder
and what I was trying to say is, if you
want to perhaps think of four and how would
you say that perhaps in Latin, it would
be tetra. Alright, it's tetra. Think of it as
being thromboembolic. So, give yourself whatever
you need to do to distinguish Class I through
Class IV. Try to do it now and get an
understanding and keep coming back
and keep applying test. So, let's
do that now, once again.
We ruled out our heart issue if you had maybe
normal EKG and normal Echo. That’s good
enough for you right now. If it’s Class
III, well, you take a look at the chest X-ray
and say that this was pneumonia, alright,
or it was COPD, you would expect there to
be quite a bit of marking on your X-ray, wouldn’t
you? So, this would then obviously tell you
that I have a serious problem with my lung
primarily and therefore causing vasoconstriction
or perhaps increased Pulmonary Hypertension.
And with Class IV, you tell me, what would
be effective in terms of ruling out, perhaps,
something like a DVT and such? You are thinking
about a VQ scan. okay. A VQ Scan. Remember,
you don’t want to get into a PE. If you
get into a PE then it will be a spiral
CT, right? So, a VQ scan will perhaps help
you for ruling out, effectively, a chronic thromboembolic
disease. Now, there are multifactorial.
Some would say that this is a Class V, whatever.
Here you go. Hematologic, systemic,
metabolic disorders. These are the other ones
that really don’t fit into Class I through
Class IV. And the reason that this is important
is now the approach, the approach of Pulmonary
Hypertension. The Pulmonary Hypertension,
it's much easier for you to rule out effectively
Class II. What is that? Where is my problem?
How is that causing Pulmonary Hypertension?
The heart. Secondary Pulmonary Hypertension.
Next. Class III. How would you effectively
rule that out? A relatively unremarkable chest
X-ray. And then Class IV, maybe a normal VQ
scan. You rule out II, III and
IV. What are you really left with right now?
Good. Class I. And so, then you start thinking
about your genes such as BMPR2, Bone Morphogenic
Protein-2, maybe drugs and so on and so forth.
Are we clear?
So, this is “Pulmonary Hypertension”,
Classes I through IV. I would be very, very
familiar with that table.