Topic 7 - Upper limb doppler

Question 1

Name the axillary arteries

Answer 1

Left subclavian
Right subclavian
Subclavian artery terminates at the level of the outer
border of the first rib to become…
Axillary artery continues until the lower border of
Teres major where it becomes…
Brachial artery at the cub fossa it divides into the radial and ulnar arteries
Ulnar artery passes deep beneath the upper forearm
muscles before emerging along the FDP muscle to
the wrist
Radial artery moves till it it passes
lateral to the carpus to the space between the 1st and
2nd MCP bones

Question 2

Name the axillary veins

Answer 2

Brachial vena comitantes join the axillary vein at the
lower border of subscap muscle
Basilic vein becomes the axillary vein at the lower
border of Teres major
Axillary vein becomes the subclavian vein
Subclavian vein joins the internal jugular vein behind
the sternoclavicular joint to form the brachiocephalic
veins which join to form the SVC
Cephalic vein passes along the radial side to perforate the pectoral fascia to join the axillary vein at the distal end
-
Basilic vein passes along the dorsal surface of the
forearm but moves ventrally in the upper arm to join
with the median vein in the cubital fossa to accompany the brachial vein
Median vein drains the front of the wrist and pain of
the hand and passes along the medial forearm to join
the basilic or median cubital vein

Question 3

Name some causes of upper limb arterial ischaemia

Answer 3

Arteritis
○ Radiation injury
○ Fibromuscular dysplasia
○ Aneurysms
○ Thoracic outlet compression
○ Atherosclerosis
○ Raynaud's syndrome
○ Hypothenar hammer syndrome
○ Embolic occlusions
○ Congenital arterial wall defects
○ Frostbite
○ Trauma

Question 4

Comment on atherosclerosis of the upper limb

Answer 4

• Less common in upper limb
• More commonly found in the proximal subclavian
  arteries
• Arterial stenosis or occlusion of the prox subclavian
  arteries can cause loss of blood pressure to the limb
  and produce ischaemic pain in the arm or hand

Question 5

What affect can significant subclavian stenosis or occlusion have?

Answer 5

Significant lesions can cause a
dramatic reduction of pressure
May partially or completely cause flow reversal in the vertebral artery to supply the distal subclavian
○this drains blood from the posterior circulation of the brain
○ Reduced blood flow can produce symptoms
related to posterior ischaemia causing
‘Subclavian Steal Syndrome’

Question 6

How can significant subclavian stenosis be diagnosed clinically?

Answer 6

Systolic brachial artery blood pressure can be
compared in both arms
Arm with subclavian stenosis will show a fall of
10-15mmHg or more compared to the contralateral
arm
In mild cases, the arm might need to be exercised to
exaggerate pressure loss through subclavian stenosis

Question 7

When does subclavian steal become subclavian steal syndrome?

Answer 7

When it produces vertebrobasilar ischaemia
• The presence of this syndrome is determined clinically and is not diagnosed by ultrasound,
• however the reversal of blood flow in the vertebral artery due to subclavian stenosis is sometimes referred to as a ‘subclavian steal’.

Question 8

What is thoracic outlet compression?

Answer 8

• difficult to diagnose as it may involve the nerves and blood vessels passing through one of the three areas of the thoracic outlet.
• has been classified in a number of ways, but most include neural compression, vascular compression and a mixed compression which may involve various degrees of neural and vascular compression.

Question 9

Describe neural compression in thoracic outlet disease

Answer 9

• vast majority of Tos
• the majority of these showing no structural cause for the symptoms on imaging or electrophysiological testing.
• This type of condition is often termed ‘disputed’ Tos and has led some to suggest that Tos does not exist.
• The remaining cases of neural compression usually involve the nerves as they pass through the scalenus triangle.

Question 10

Describe Compression of the subclavian artery or vein in thoracic outlet disease

Answer 10

• constitute a minority of cases
imaging studies are important to define whether compromise of the vessels is present and what structures are causing it.
• Typically this will occur in either the scalenus triangle or costoclavicular space (or both).
• may involve a number of bone abnormalities, presence of fibrous bands, muscular weakness or scar tissue from previous injuries
the use of Xray, CTA, MR/A , electrophysiology and ultrasound are needed to confirm the site of compression and the structures causing it.
• Once diagnosed, conservative treatment is usually the first course of action and surgical procedures are reserved for non resolving symptoms

Question 11

What are the ain causes of upper limb thrombosis?

Answer 11

• Genetic coagulation disorders
• Repeated compression of the thoracic outlet
• Insertion of central venous catheters or insertion of needles for blood sampling or drug use
• Trauma from a broken clavicle or penetrating wound from knife or gunfire

Question 12

What are the three compartments of the thoracic outlet?

Answer 12

1. the interscalene triangle
2. costoclavicular space
3. retropectoralis minor space

Question 13

What are the three syndromes encountered in thoracic outlet compression?

Answer 13

o neurogenic syndrome
o arterial syndrome
o and venous syndrome.

Question 14

What are the symptoms of neurgenic TOS?

Answer 14

the symptoms may be sensory or motor, although subjective sensory symptoms of pain and paresthesia predominate

Question 15

What are the symptoms of arterial TOS?

Answer 15

symptoms are caused by arterial insufficiency.
They include weakness, cold, and pain in the extremity, caused by ischemic neuritis of the brachial plexus.
In the case of severe compression, subclavian artery thrombosis with peripheral embolization can be observed.

Question 16

What are the symptoms of venous TOS?

Answer 16

swelling and cyanosis of the extremity, with pain, a feeling of heaviness in the upper limb, and venous distention of the upper arm and shoulder region.
Acute subclavian-axillary vein thrombosis refers to a Paget-Schroetter syndrome or effort thrombosis

Question 17

What are some Skeletal and bone abnormalities that may cause TOS?

Answer 17

o Cervical rib
o elongated C7 transverse process
o Exostosis or tumor of the first rib or clavicle
o Excess callus of the first rib or clavicle

Question 18

What are some soft tissue abnormalities that may cause TOS?

Answer 18

•	Soft-tissue abnormalities 
o	Fibrous band
o	Congenital muscle abnormalities 
•	Acquired soft-tissue abnormalities 
o	Posttraumatic fibrous scarring
o	Postoperative scarring

Question 19

How can posture cause TOS?

Answer 19

o Poor posture and weak muscular support in thin women

Question 20

What is important when finding the subclavian artery on ultrasound?

Answer 20

• Using the common carotid arteries as a guide is important so that you are confident of identifying the subclavian artery rather than just following the carotid artery.
Subclavian vein is found in a similar way using the jugular vein

Question 21

How is stenosis identified in the subclavian artery?

Answer 21

The Subclavian arteries have a characteristic multiphasic waveform shape with peak systolic velocities as high as about 180cm/s
although some literature suggests a lower value than this as a criteria for stenosis.
Whatever the velocity the presence of B-mode and colour evidence of narrowing should be present to support your Doppler measurements.

Question 22

What does the normal axillary vein look like on ultrasound?

Answer 22

• The normal artery again shows a multiphasic waveform with a peak velocity of less than about 180cm/s.

Question 23

What are the main criteria for detecting thrombosis in the axillary vein

Answer 23

• The vein can show mild pulsation
it can be augmented by compression of the forearm or upper arm.
• The presence of clot in the axillary vein can make it difficult to image
detecting echogenic clot or identifying the presence of colour filling defects are the two main criteria to identify thromboses.

Question 24

How does a stenosis appear in the brachial artery?

Answer 24

usual colour filling and b mode thrombus
• The velocity in the brachial artery varies but focal changes of 2 fold or more in peak systolic velocity indicate a greater than 50% stenosis.

Question 25

Comment on stenosis grading in the upper limb

Answer 25

• As there is no specific criteria for grading upper limb artery velocities, it is unwise to try to grade a stenosis with any more accuracy than this.

Question 26

How does almost occluded and occluded arteries appear in the upper limb

Answer 26

Same as all others
• Complete occlusion will be suggested by the absence of colour flow at machine settings which optimise low flow.
• Arteries which are almost occluded will show ‘trickle flow’ which will be displayed as a narrow and irregular low velocity colour channel defined within the B-mode image of the lumen

Question 27

What is an AV fistula?

Answer 27

• Arterio-venous fistula can be created surgically between a superficial vein and its adjacent artery.
• These fistula are created to form a vein with a high flow rate which can be used to pass through a blood filtering system
• Arterio-venous fistula are created by directly connecting a vein and artery by forming an anastomosis or using a synthetic tube as a communication.

Question 28

What is the most common type of fistula created?

Answer 28

between the cephalic vein and radial artery in the distal forearm.

Question 29

Where are radiocephalic fistulas most commonly stenosed?

Answer 29

• prone to form stenosis in its proximal segment adjacent to the anastomosis with the radial artery
• or in its distal segment near the confluence with the axillary vein (cephalic arch).

Question 30

What is another common fistula (not radiocephalic) and where might it stenose?

Answer 30

• Brachio basilic fistula may also form stenosis in its proximal segment but more commonly narrows distally in its cephalic arch more frequently than radio-cephalic fistula.

Question 31

How should fistula be imaged using ultrasound?

Answer 31

o from their inflow artery (radial or brachial)
o through the fistula
o and into the outflow vein (axillary vein).
• A linear array transducer is usually most appropriate with a frequency above 5MHz.

Question 32

How can a fistula stenosis be recognised on ultrasound?

Answer 32

• Velocity ratios, absolute velocities, colour aliasing and narrowing on B-mode and colour imaging all contribute to the recognition of significant stenosis.
• Stenosis at the proximal or distal ends of the fistula are usually characterised by narrowing of the colour band and considerable spectral broadening over and above that normally seen in the high flow rate of a fistula.
• Velocities in excess of 300cm/s usually suggest a stenosis