00:01
Here's an image of bypass surgery.
00:04
On this angiogram,
the arrow demonstrates a
mid-superficial femoral artery occlusion.
00:10
How do we fix this problem?
That's right.
00:14
With a vascular bypass.
00:16
Here is a schematic of what
happens in vascular surgery bypasses.
00:20
I enjoy vascular surgery
because, conceptually, it's very straightforward.
00:25
We need to have excellent inflow.
00:28
We need to have excellent outflow.
00:30
And between the two,
a bridging of conduit.
00:34
Any breakdown in any of those three elements
can lead the patient to peripheral
arterial occlusive disease.
00:40
As you can see in this schematic,
the inflow on the left of the screen
and the outflow appear normal in size.
00:47
However, this segment in
the middle is stenotic.
00:51
There's going to be a significant flow
and pressure differential
as the vessel diameter goes
from normal to stenotic or occlusive.
01:00
Vascular surgeons will
then bypass this region
as demonstrated by the arc.
01:05
In general, the bypass has the longest patency
if we’re able to use a autogenous
vein as opposed to synthetic graft.
01:15
Sometimes, it's not an option
and grafts are used.
01:20
Let me pose another question to you.
01:23
Thus far, we've discussed
atherosclerotic arterial occlusive disease.
01:27
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.
01:41
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.
01:49
And the contralateral extremity
has strongly palpable posterior,
tibial and dorsalis pedis pulses.
01:56
What's going on here?
I’ll give you a second to think about this.
02:03
That's right.
02:04
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.
02:13
This is considered an emergency.
02:16
Very important,
if a clinical scenario is presented to you,
this is considered an acute threatened extremity
and intervention needs to occur right away.
02:26
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.
02:38
The PTT goal is titrated and is variable.
02:42
This is to reduce further propagation of clot.
02:45
Next, most patients with threatened extremities
require what's called a surgical embolectomy.
02:51
I’ll get to that in a second.
02:53
And lastly, when the
embolectomy is completed,
we want to make sure
that flow has been restored.
02:58
This is done by an
on-table angiography.
03:02
Here's an example of an embolectomy.
03:05
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.
03:17
The idea is, as a balloon is withdrawn,
clots are brought out through the arteriotomy.
03:22
Here, you can see three large clots.
03:24
These clots, remember, in our patient,
came from atrial thrombus.
03:29
After the clot is dislodged,
we do an on-table
completion angiography.
03:34
The angiogram then should show
a normal flow to the distal vessels.
03:40
If the angiography shows persistent occlusion,
you should try the Fogarty catheter again.
03:46
And as I mentioned,
don't forget to do a completion angiography
before closing the incision.
03:52
I’d like to pose another question to you.
03:54
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?
That's right.
04:13
You’re thinking compartment syndrome.
04:17
Here's a picture of a four-compartment fasciotomy.
04:20
Remember, any ischemic
time greater than six hours
puts the patient at a high
risk of compartment syndrome.
04:28
Compartment syndrome occurs
when edema in the region surpasses
the ability of inflow and venous obstruction.
04:37
In these situations,
it's usually related to a re-perfusion injury.
04:41
Remember, pulselessness,
coldness of the foot
are also late signs
of arterial occlusive disease
or embolic phenomenon.
04:51
Have a low threshold to
perform a four-compartment fasciotomy.
04:54
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.
05:05
Now, let's move on to a different topic
called Subclavian Steal Syndrome.
05:09
It's rarely seen, but a high-yield topic.
05:13
Subclavian Steal Syndrome occurs
with retrograde vertebral artery flow
due to a subclavian artery stenosis or occlusion.
05:23
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.
05:34
As a result of the retrograde vertebral artery flow,
the patient can experience
syncope, vertigo and confusion.
05:41
This is due to the stealing of
the blood from the vertebral artery.
05:45
As a reminder,
the vertebral artery supplies
the posterior circulation.
05:49
You’ll remember, of course,
that the cerebellum
contributes to one's
positional sense and stability.
05:56
In severe cases of subclavian steal
and subclavian artery stenosis,
limb ischemia may occur.
06:04
And the treatment is a very advanced
carotid to subclavian revascularization.
06:10
Here is a schematic
depicting normal arch anatomy.
06:15
Notice the common carotid
takeoff on the left side
and the subsequent vertebral artery takeoff.
06:21
Now, let's review some high-yield information
from peripheral vascular disease.
06:26
Remember, for patients with claudication,
surgery is not the first line therapy.
06:31
You can add cilostazol,
exercise, smoking cessation.
06:36
Remember, surgery is not the first line therapy.
06:41
Next, patients who present
with a cold lake or pulseless
should be considered a surgical emergency.
06:47
No further workup should be done.
06:49
The patient should be taken
to the operating room
and you can do your diagnoses
and therapeutics on the table.
06:55
Therapeutically and diagnostically,
angiographies are very important
and can be performed intraoperatively.
07:04
And remember,
any patient with a period of extremity ischemia
are at high risk for compartment syndrome.
07:10
Before leaving the operating room,
consider performing a four-compartment fasciotomy.
07:16
Thank you very much for joining me
on this discussion of peripheral vascular disease.