00:01
Now let's talk about the
work-up for ischemic stroke
and evaluating the
causes of the stroke.
00:07
And again, we think about
strokes coming from three areas.
00:10
They can come from the heart,
the blood vessels in the neck,
or the blood vessels
in the brain.
00:15
And so we do diagnostic testing
to work up each of those areas.
00:19
First, let's talk about how we
evaluate the blood vessels in the neck.
00:23
And there's really two studies
that we can use to do that.
00:25
The carotid ultrasound or
the (CTA) CT angiography.
00:30
Carotid ultrasound uses
ultrasound or sonography
to evaluate the blood
vessels in the neck,
and we often combine it with
transcranial doppler or TCD
to evaluate the blood
vessels in the brain.
00:43
We can also do a CTA or CT
angiography of the head and neck,
which also evaluates the patency
or openness of the blood vessels
in the neck and the head.
00:53
We're looking for
carotid artery stenosis
in carotid artery
stenosis more than 70%
where the lumen of the carotid
artery is narrowed by at least 70%
in narrowed by at least 70% in a symptomatic patient
warrants surgical consideration.
01:08
Carotid artery stenosis more than 60%
in an asymptomatic individual,
particularly men with diabetes also
warrants surgical consideration.
01:16
Those patients are at
higher risk of stroke.
01:18
And in those patients we want to intervene
to prevent stroke before it happens.
01:24
What about evaluating the heart?
Well, for there we really use two tests,
the transthoracic echocardiogram or EKG
to evaluate the heart
and its function.
01:34
EKG and telemetry evaluate for
paroxysmal atrial fibrillation,
which increases the likelihood or
risk of cardiac embolic strokes.
01:43
The transthoracic echocardiogram looks
at the ejection fraction and atrial size.
01:48
Patients with reduced ejection fraction
are at risk for blood clot development
in the heart which can
embolize to the brain.
01:54
Enlarged atrial size,
increases the risk of paroxysmal Afib
and would warrant further evaluation
for afib in those patients.
02:03
We can also perform
a bubble study
where we use bubbles
injected into the veins
to evaluate a hole in the
heart patent foramen ovale.
02:12
This is a symptomatic
very small hole
from a vestigial structure
that exists in the heart
and can be a nidus for right
to left transfer of a blood clot.
02:22
Patients who may have venous
thromboembolism or a DVT
that embolizes can
pass through the PFO
and then travel to the
brain and cause a stroke.
02:31
So the presence of a PFO warrants further
evaluation for a DVT in those patients.
02:37
And then lastly, we want to evaluate
potential risk factors for stroke
when we perform a TSH to evaluate
for hyper or hypothyroidism.
02:47
Hyperthyroidism is associated
with atrial fibrillation risk.
02:51
Hypothyroidism is associated
with hypertriglyceridemia.
02:55
We can work up for
diabetes and A1C
of greater than 7
raises risk for stroke.
03:01
And really the goal
is an A1C less than 7.
03:04
This is one of the most
important risk factors
to modify in addition to
blood pressure and LDL.
03:12
LDL or low-density lipoprotein is one
of the important cholesterol measures.
03:18
There's a linear risk with reduction
in LDL and reduction in stroke.
03:23
And we'd like to see a
low LDL and a high HDL.
03:27
Our LDL goal for patients who have
had a stroke is than less than 100
unless the patient has diabetes
where the goal is less than 70.
03:36
And then also important is managing blood
pressure, high blood pressure hypertension
during the acute or hyper acute period
right when patients present with a stroke,
we allow permissive
hypertension.
03:46
And that's a little bit of increased blood
pressure right at that early period of time
to perfuse that area of penumbra
around the ischemic infarct.
03:55
But ultimately we want
to move to normalization
of the patient's blood pressure with
a goal blood pressure of 120 over 70
and we use medicines like ACE
inhibitors, diuretics,
beta blockers,
calcium channel blockers and others.