Thanks for joining me
on this discussion of carotid stenosis
in the section of vascular surgery.
Carotid stenosis is a very common disease
and there are some risk factors,
particularly puts you at higher incidence.
For example, smoking.
In fact, smoking is a high-risk factor
for most vascular diseases.
There is some association with
increased alcohol intake
and, of course,
like any peripheral vascular disease,
when one has one peripheral vascular disease,
one is at a higher association for another.
In this situation,
patients with coronary artery disease
also may have carotid disease.
This is an important distinction,
because when patients have
coronary artery disease,
also think about working them
up for bilateral carotid diseases.
Let's discuss the pathophysiology of
carotid diseases and atherosclerotic plaques.
Here's a depiction of a
common carotid bifurcation.
It's, of course, situated in your neck.
You can feel your own carotid pulses.
Atherosclerotic plaques are dense in lipids
and they usually occur
at the carotid bifurcation.
This is particularly because,
at the bifurcation,
laminar or straight-line
flow becomes turbulent.
And as turbulent flow
occurs at the bifurcation,
it perpetuates worsening of
the atherosclerotic plaque.
At some point,
the plaque becomes so thick
that it actually narrows
the lumen of the vessels.
That's when you become symptomatic.
What are some common
findings of carotid stenosis?
One might actually hear a carotid bruit.
When you listen to a patient
who has a carotid stenosis,
the carotid bruit actually sounds like,
well, turbulent flow,
as I previously described.
Some patients will also describe
transient ischemic attacks,
also known as TIAs.
In these select patients,
it's a warning sign.
Patients may have intermittent stroke
symptoms that are self-contained.
They may have completely resolved
by the time the patient
even presents to your office
or the emergency room,
but don't lose these patients to follow up.
They may actually have significant carotid disease.
This is a depiction of a curtain drawn down
or a shade over a window.
And that's a classic
description of amaurosis fugax.
That's the transient monocular blindness
that's associated with plaques.
And those plaques
may be distributing themselves
into the ophthalmic artery.
Patients may actually
have CVAs or stroke.
CVA stands for cerebrovascular accidents.
This is most likely due to
portions of the atherosclerotic plaque
breaking off and being embolic.
Also, when the channel is so stenotic
that the flow is inadequate,
one may actually have a
broader distribution ischemic stroke.
Labs are unlikely to be helpful to you,
but it is very important to
screen for carotid disease
when you have high suspicions.
How do we screen for carotid disease?
I’ll give you a second
to think about it.
Carotid duplex ultrasonography.
As with all ultrasounds,
the results and accuracy of these tests
are heavily operator dependent.
Let's say the clinical scenario is a patient
who presents to your office.
They describe symptoms consistent
with TIAs or amaurosis fugax.
The next step of management will be
obtain a carotid duplex ultrasound.
Duplexes are helpful
not only because they give
you anatomic information,
but more importantly,
for stenotic vessels,
they give you velocity information.
flow through a smaller diameter
is usually at higher velocities.
That’s simple physics. A certain velocity,
as described as centimeters per second,
is indicative of a
percentage of carotid stenosis.
This is an approximation of course.
For many years,
angiography was the gold standard.
I'm talking about the
invasive interventional angiography,
not the spiral CAT scan angiographies.
In this representative invasive angiography,
the arrow points at an area
that’s most likely
representative of a plaque.
Note, it's very close
to the bifurcation.