Here's an image of bypass surgery.
On this angiogram,
the arrow demonstrates a
mid-superficial femoral artery occlusion.
How do we fix this problem?
With a vascular bypass.
Here is a schematic of what
happens in vascular surgery bypasses.
I enjoy vascular surgery
because, conceptually, it's very straightforward.
We need to have excellent inflow.
We need to have excellent outflow.
And between the two,
a bridging of conduit.
Any breakdown in any of those three elements
can lead the patient to peripheral
arterial occlusive disease.
As you can see in this schematic,
the inflow on the left of the screen
and the outflow appear normal in size.
However, this segment in
the middle is stenotic.
There's going to be a significant flow
and pressure differential
as the vessel diameter goes
from normal to stenotic or occlusive.
Vascular surgeons will
then bypass this region
as demonstrated by the arc.
In general, the bypass has the longest patency
if we’re able to use a autogenous
vein as opposed to synthetic graft.
Sometimes, it's not an option
and grafts are used.
Let me pose another question to you.
Thus far, we've discussed
atherosclerotic arterial occlusive disease.
What if the patient has a
history of atrial fibrillation
and now presents with an acute leg pain?
What are your thoughts?
What's going on in your mind?
I'll give you a second to think about this.
Let's say, now you go to the bedside
and examine the patient,
but you feel no pulse in the
dorsalis pedis or posterior tibial vessels.
And the contralateral extremity
has strongly palpable posterior,
tibial and dorsalis pedis pulses.
What's going on here?
I’ll give you a second to think about this.
The atrial fibrillation may
have caused the clot,
and that clot – called an embolus
– likely dislodged from the heart
and is now occluding a distal vessel.
This is considered an emergency.
if a clinical scenario is presented to you,
this is considered an acute threatened extremity
and intervention needs to occur right away.
If the question suggests,
what is the next step of management,
do you know what to do?
First, we will usually use an
unfractionated heparin drip.
The PTT goal is titrated and is variable.
This is to reduce further propagation of clot.
Next, most patients with threatened extremities
require what's called a surgical embolectomy.
I’ll get to that in a second.
And lastly, when the
embolectomy is completed,
we want to make sure
that flow has been restored.
This is done by an
Here's an example of an embolectomy.
A Fogarty catheter is inserted
into the vessel of interest,
past the area where we
think that there may be a clot,
the balloon is inflated and
the entire catheter is withdrawn.
The idea is, as a balloon is withdrawn,
clots are brought out through the arteriotomy.
Here, you can see three large clots.
These clots, remember, in our patient,
came from atrial thrombus.
After the clot is dislodged,
we do an on-table
The angiogram then should show
a normal flow to the distal vessels.
If the angiography shows persistent occlusion,
you should try the Fogarty catheter again.
And as I mentioned,
don't forget to do a completion angiography
before closing the incision.
I’d like to pose another question to you.
What if this patient that
had the atrial fibrillation
and suspected of an embolic phenomenon
and an acute threatened extremity
has been experiencing a
cold and pulseless extremity
for now eight hours?
What’s going on in your mind?
What’s the next step of management?
You’re thinking compartment syndrome.
Here's a picture of a four-compartment fasciotomy.
Remember, any ischemic
time greater than six hours
puts the patient at a high
risk of compartment syndrome.
Compartment syndrome occurs
when edema in the region surpasses
the ability of inflow and venous obstruction.
In these situations,
it's usually related to a re-perfusion injury.
coldness of the foot
are also late signs
of arterial occlusive disease
or embolic phenomenon.
Have a low threshold to
perform a four-compartment fasciotomy.
Remember, you can do all
the vascular bypass you want,
patient is still going
to lose their leg or foot
if you don't complete your
four compartment fasciotomy.
Now, let's move on to a different topic
called Subclavian Steal Syndrome.
It's rarely seen, but a high-yield topic.
Subclavian Steal Syndrome occurs
with retrograde vertebral artery flow
due to a subclavian artery stenosis or occlusion.
As a result, you may find a
reduced ipsilateral upper extremity,
pulse or a blood pressure,
typically described as a differential pressure
between the affected arm and the normal arm.
As a result of the retrograde vertebral artery flow,
the patient can experience
syncope, vertigo and confusion.
This is due to the stealing of
the blood from the vertebral artery.
As a reminder,
the vertebral artery supplies
the posterior circulation.
You’ll remember, of course,
that the cerebellum
contributes to one's
positional sense and stability.
In severe cases of subclavian steal
and subclavian artery stenosis,
limb ischemia may occur.
And the treatment is a very advanced
carotid to subclavian revascularization.
Here is a schematic
depicting normal arch anatomy.
Notice the common carotid
takeoff on the left side
and the subsequent vertebral artery takeoff.
Now, let's review some high-yield information
from peripheral vascular disease.
Remember, for patients with claudication,
surgery is not the first line therapy.
You can add cilostazol,
exercise, smoking cessation.
Remember, surgery is not the first line therapy.
Next, patients who present
with a cold lake or pulseless
should be considered a surgical emergency.
No further workup should be done.
The patient should be taken
to the operating room
and you can do your diagnoses
and therapeutics on the table.
Therapeutically and diagnostically,
angiographies are very important
and can be performed intraoperatively.
any patient with a period of extremity ischemia
are at high risk for compartment syndrome.
Before leaving the operating room,
consider performing a four-compartment fasciotomy.
Thank you very much for joining me
on this discussion of peripheral vascular disease.