Vascular Technology
Lecture 6
Ultrasound Assessment of the Upper Extremity
 Anatomy of the upper extremity including palmar
arches
 Doppler Segmental Pressures of the upper extremity
 The Allen Test
 Duplex/Color Flow Imaging (UE)
 Upper Extremity Arterial Doppler Protocol
 1. Subclavian
artery
• Runs laterally to outer border of 1st rib becoming the
axillary artery
• Some branches: vertebral, thyrocervical,
costocervical.
 2. Axillary
artery
• After giving off several branches, becomes brachial
artery
 3. Brachial
artery
• Branches into the radial and ulnar arteries a the
inner aspect of the elbow (AKA the antecubital fossa)
 4. Radial
artery
• Travels down lateral side of forearm into hand,
branching to form:
 Superficial palmer (volar) arch
 Terminates in deep palmer arch by joining deep
branch of ulnar artery
 5. Ulnar
artery
• Travels down medial side of forearm into hand,
branching to form:
 Deep palmar (volar) branch
 Terminates in superficial palmar arch
 Predominate source of blood flow to the hand
 6. Superficial
palmar (volar) arch
includes:
• Distal portion of the ulnar artery
• Branch of the radial artery
 7. Deep
palmar arch includes:
• Deep palmar arch of the ulnar artery
• Distal portion of the radial artery
 8. Digital
arteries arise from the palmar
arches and extend into the fingers
dividing into lateral and medial
branches.
Patient positioning:
• Supine with arms relaxed at the patient’s side
• Cuffs should be on snug, but not too tight.
Technique:
•
•
12 x 40 cm cuff placed snugly on the upper
arm: 10 x 40 cuff on the forearm bilaterally
Brachial artery used to obtain upper arm BP;
Radial and ulnar arteries used to obtain the
forearm pressure.
 Pressures
are combined with Doppler
velocity wave forms from the sites
previously describe.





1) Bilateral brachial arm pressures no more than 20 mmHg
2) Finger/Brachial Index
a. Normal >0.75
b. Abnormal <0.75
3) Pressure measurements between adjacent cuff sites on
the same arm should
not differ by more than 10 mmHg (brachial and forearm)
4) Pressure measurements differences at the same cuff
level on opposite arms
should not exceed 20 mmHg
5) The pressures in the radial and ulnar arteries should be
within 5-10 mmHg of one
another. A pressure difference >= 20mmHG indicates
obstruction in the vessel with
the lower pressure
What mm/Hg difference from arm to
arm constitutes an abnormal upper
extremity segmental pressure?
 Pressure
measurements differences at
the same cuff level on opposite arms
should not exceed 20 mmHg.
Doppler Segmental Pressures of the Upper Extremity

What is the Allen Test and how is it performed?
The test is performed to estimate palmar arch patency. A
technologist compresses the radial artery while patient closes
ipsilateral fist to cause pallor, but in the meantime, this action
will increase resistance.

What mm/Hg difference from arm to arm constitutes an
abnormal upper extremity segmental pressure?
The differences of pressure measurements at the cuff level on
the other arms should not go over than 20 mmHg.
 Only
done to evaluate patency of the
palmer arch
The Allen test
 The
hand is normally supplied by blood
from the ulnar and radial arteries.
 The arteries undergo anastomosis in the
hand. Thus, if the blood supply from one
of the arteries is cut off, the other artery
can supply adequate blood to the hand.
 A small amount of people lack this dual
blood supply.
1) The hand is elevated and the patient/person is
asked to make a fist for about 30 seconds.
 2) Pressure is applied over the ulnar and the
radial arteries so as to occlude both of them.
 3) Still elevated, the hand is then opened. It
should appear blanched (pallor can be observed
at the finger nails).
 4) Ulnar pressure is released and the color
should return in 7 seconds.
 Inference: Ulnar artery supply to the hand is
sufficient and it is safe to cannulate/prick the
radial
 If color does not return or returns after 7–10
seconds, the test is considered positive and the
ulnar artery supply to the hand is not sufficient.
The radial artery therefore cannot be safely
pricked/cannulated.

 Normal
• Reappearance of the normal color to indicate the
ulnar artery is providing flow to the palmar arch
 Abnormal
• Color does not reappear to indicate an ulnar
artery occlusion or palmar arch obstruction
 Excessive
dorsiflexion of wrist may
compress radial and ulnar arteries
leading to a false positive test.
 If hand is opened, fingers forcibly
extended; the skin over palm can be
stretched, which could lead to pallor due
to compression of small vessels
 Use
a PPG (photoplethysomography) on
the index finger to document arterial
pulsations before and after the “clinched
fist”.
 Although more difficult to compress, the
ulnar artery can be evaluated similarly to
assess radial artery flow.
 Capabilities
• Localize stenosis/occlusion; evaluate degree of
stenosis
• Determine the presence/absence of aneurysm
• Post-op study: hemodialysis access or arterial
bypass graft
• Direct Artero- Venous fistula (AVF) or other
unusual abnormality
 Limitations
• Limited access to extremity (e.g.,) dressings,
skin staples or sutures, open wounds IV site…
• Pertaining to hemodialysis access grafts:
 Graft angulation
 Difficult to adequately evaluate the outflow vein in an
obese patient
 Patient
positioning
• Patient is supine with small pillow under head
• Extremity close to examiner
• Arm is at a 45 degree angle from the body, and
extremity rotated “Pledge Position”
 Physical
Principles
• Duplex scanning: combination of real-time B-
mode imaging (gray scale evaluation) and
Doppler spectral analysis
• Doppler Color Flow Imaging: Doppler
information is displayed on image after
evaluated for phase (direction toward or away
from the transducer) and its frequency content
(hue or shade of the color)
• Sample size for acquiring pulsed Doppler
information is usually 1-1.5mm. Size is increased
incrementally if needed.
 Technique: Native Arteries
• Utilize a 7 or 5 MHz linear array transducer
• Neck vessels identified with attention to
innominate artery on the right. The LCCA
braches off the Arch.
• Color / duplex scanning is also used to evaluate
the following:
 Subclavian
 Axillary
 Brachial
 Radial
 Ulnar
 Palmar arch (if needed)
 NOTE: It
is uncommon for arteries in the
upper extremities to become stenotic.
Main indication for ultrasound
assessment is for evaluation of dialysis
access grafts.
Dialysis access is an entranceway into the
bloodstream that lies completely beneath
the skin and is easy to use.
The access is usually in the arm, but
sometimes in the leg, and allows blood to
be removed and returned quickly,
efficiently, and safely during dialysis or,
less commonly, for other procedures
requiring frequent access to the
circulation.
 Hemodialysis
Access
• Auscultate the access for bruit and or palpate for
a “thrill” (vibration). A patent dialysis access, as
well as a stenotic one can produce a “thrill.”
• Utilize a 7 or 5 MHz linear array transducer
 Inflow
artery
 Arterial anastomosis
 Continue through the body of the graft
 Observe of aneurysm, puncture sites,
peri-graft fluid
 If color available, observe the image for
flow changes, turbulence, flow channel
changes
 Venous anastomosis
 Outflow vein
 NOTE: Dialysis
access (e.g. BresciaCimino fistula) assessment sites include:
inflow artery, anastomosis, outflow vein
 Includes
an evaluation of bilateral
extremity arterial waveforms of the
common carotid, subclavian, brachial,
ulnar, and radial arteries utilizing
spectral Doppler. The goal is to
document any hemodynamic changes
related to vessel narrowing or stenosis
 Patient
Prep: None
 Patient is instructed to remove clothing from the waist
up- gown open in the front
Transducer:

The highest frequency linear transducer
possible- usually 5 to 15 MHz.
•
Continuous wave “Pencil-Probe is transducer of
choice.
Paperwork:
Fill out Upper Extremity Arterial Doppler Worksheet
completely (Department specific). Document reason
for exam and all pertinent history. Record all
measurements and fill in comments. Obtain reports of
previous exams or other pertinent studies.

 Patient
is instructed to relax spine on the
bed. A blood pressure cuff is placed above
the brachial artery on the upper arm. The
cuff is inflated and a systolic pressure of the
brachial artery is obtained. This number is
documented. The brachial artery spectral
waveform is evaluated for flow
characteristics (Triphasic, biphasic, or
monophasic). Pressure differences are
compared segmentally and contra laterally.
A
blood pressure cuff is placed on the
forearm and systolic pressures are
obtained of the radial and ulnar arteries.
Once again, flow characteristics are
evaluated and ratios are calculated using
the brachial pressure.
 Examination is repeated on the
contralateral arm.
 The
following spectral Doppler images
must be obtained during the procedure:
•
•
•
•
•
•
Right Carotid
Right Subclavian
Right Axillary
Right Brachial
Right Radial
Right Ulnar
• Waveform analysis is repeated on the left arm