welcome to a Stanford medicine 25 video
on ankle brachial index hi I'm John
Cooke I'm a professor of medicine in the
division of cardiovascular medicine here
at Stanford and today I'm going to show
you how to detect proof our tool disease
in the office setting using the ankle
brachial index which is simply a measure
of ankle pressure divided by the
pressure at the arm the brachial
pressure about 8 million people in the
country with profe arterial disease but
only about 30% have been diagnosed but
with a simple handheld Doppler and a
blood pressure cuff measurements at the
ankle and at the arm can give you an
ankle brachial index to tell you whether
or not the person in your office has
prefer our Childers ease everyone over
the age of 60 and anyone over the age of
50 that's diabetic or smoker should have
this test done to determine if they have
prior to these because we have life and
limb saving medical therapies for these
individuals like ACE inhibitors and
statins and antiplatelet agents and even
beta blockers can be used in patients
with prior to disease so let's get
started so for the ankle brachial index
we need a handheld Doppler and we also
need some ultrasonic gel and we need
blood pressure cuff we want the patient
in a dimly lit a quiet room for about 10
minutes relaxed so the blood pressure
stabilizes okay
so what we're going to do first is
measure the pressure at the arm and
we're going to use the same technique to
measure pressure at the arm that we're
going to use to measure pressure at the
ankles so I'm putting the blood pressure
cuff around the arm right now you want
it to be snug and now I'm going to put
some ultrasound gel right here in the
antecubital space over the brachial
artery so my fingers are on the brachial
artery there having done that now I can
listen for the signal with my handheld
Doppler
no that's a nice signal
it's a normal triphasic pulse waveform
that we're hearing with our Doppler out
okay now what we're going to do is we're
going to blow up the blood pressure cuff
until we no longer hear a signal okay
we're going to gradually release the
pressure gradually release the pressure
until we hear the signal again okay he's
got a blood pressure of 100 millimeters
systolic
so that becomes our denominator for the
ankle brachial index now there are two
vessels that were interested in in
measuring the ankle brachial index so
two vessels in the foot
one is the dorsalis pedis which is right
about here where my fingers the
posterior tibial is right behind the
medial malleolus if you can't feel the
dorsalis pedis bilaterally it could be
normal that could be a normal finding
but you should always be able to feel a
posterior tibial artery if you can't
feel the posterior tibial artery that's
always abnormal so once again you apply
the blood pressure cuff and in this case
we're going to be applying it right
above the Millea lie again you want snug
and you'll put the gel right behind the
medial malleolus and the over the dorsum
of the foot so let's just take a listen
to the waveforms here so that's a very
nice pulse waveform strong biphasic and
that's normal in an adult and let's just
take a listen over the posterior tibial
nice pulse waveform there now
let's check the pitot pressure
okay I'd blown the cuff up and I'm
slowly releasing it and that was about
110 millimeters of mercury that roar
that you just heard that was venous
return I'll actually demonstrate that
this is the arterial signal you can hear
that I'm going to squeeze the foot and
you'll hear the venous return moving
past that Doppler transducer that's when
it's returned well we'll talk about of
the venous exam at another time but one
can determine if someone has a venous
obstruction or venous insufficiency we
using this handheld Doppler now I've
shown you how to do the posterior tibial
pulse waveform I get the pressure there
you do the same thing over the anterior
tibial you do that for both pedal pulses
and each extremity and then what is done
to create the ankle brachial index is
you take the highest of the brachial
pressures that you've measured and that
becomes your denominator the numerator
is the highest ankle pressure in the
right leg and the highest ankle pressure
that you've measured in the left leg leg
to give you the right and the left a B
is respectively sometimes you'll find
that the pressures are slightly
different between the anterior tibial
and the posterior tibial artery and by
convention we express the higher those
two pressures over the brachial pressure
to get the ankle brachial index for that
foot and we calculate the ankle brachial
index for each each foot to conclude
with the example in our video the
patient's highest right ankle pressure
was 110 which is divided by the highest
of the blood pressures on both
arms which was 100 giving the right
ankle brachial index of 1.1 an ankle
brachial index of 1 to 1.4 is normal
whereas a value of 0.9 to 1 is
acceptable neither require any
intervention a value of 0.8 to 0.9
suggest some arterial disease and
treatment of risk factors is advisable a
value of 0.5 to 0.8 suggest moderate our
trill disease where a value of less than
0.5 suggests severe arterial disease
either category should be referred to a
vascular specialist and finally a value
greater than 1.4 can be an indication of
calcification or vessel hardening which
also should be referred this has been a
Stanford medicine 25 video on ankle
brachial index thanks for watching the
preceding program is copyrighted by the
Board of Trustees of the Leland Stanford
junior University please visit us at
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