Topic 6 - Lower Limb Arterial Disease Flashcards

1
Q

List the main arteries supplying the lower limbs

A
Aortic bifurcation
Common Femoral artery
Profunda Femoris (Deep Femoral)
Superficial Femoral Artery
Popliteal Artery
Anterior tibial artery
Posterior Tibial artery
Peroneal artery
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2
Q

What does the aorta bifurcate to become?

A
  • divides into the left and right common iliac arteries.
  • The right common iliac artery then passes ventral to its vein and divides into the external and internal iliac artery at the level of the sacro-iliac joint.
  • The internal iliac artery passes deep to pelvis
  • the external iliac passes along the psoas muscle to the mid point of the inguinal ligament to become the common femoral artery.
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3
Q

Describe the femoral artery

A
  • begins just above the inguinal ligament
  • continues along the femoral sheath before bifurcating into the superficial femoral and profunda femoris arteries.
  • It is located at the midpoint of the inguinal ligament.
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4
Q

Describe the profunda artery

A
  • main branch of the femoral artery
  • usually consists of a single branch
  • lies deep and slightly lateral to the superficial femoral artery
  • before passing deep into the thigh and branching extensively it may continue for some length as a definable arterial segment deep to the femoral vein.
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5
Q

Describe the superficial femoral artery?

A
  • Begins at the bifurcation of the common femoral artery
  • runs a straight course from the base of the femoral triangle to the tip of the femoral triangle at the adductor hiatus, which is about 10cm or 1hand’s width above the knee joint
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6
Q

Describe the popliteal artery

A
  • begins in the lower thigh at the adductor hiatus
  • finishes below the knee
  • it bifurcates below the knee at the lower border of the popliteus muscle into the anterior tibial artery and tibio-peroneal trunk (about 2.5cm below the tibial tuberosity).
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7
Q

Describe the anterior tibial artery

A
  • begins at the bifurcation of the popliteal artery at the level of the tibial tuberosity
  • runs anteriorly to the interosseous membrane where it courses distally on the membrane to the dorsal surface of the foot to become the Dorsalis Paedis Artery (DPA)
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8
Q

Describe the posterior tibial artery

A

• strictly begins at the bifurcation of the popliteal artery but it is often considered to begin at the bifurcation of the tibio-peroneal trunk about 2.5cm below the tibial tuberosity and courses posterior to the tibia to the lower border of the medial malleolus.

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9
Q

Describe the peroneal artery

A
  • begins as a branch of the posterior tibial artery about 2.5cm below the tibial tuberosity
  • is commonly considered to branch from the tibio-peroneal trunk.
  • The peroneal artery runs along the fibula and lies in close proximity to the shadow caused by the fibula.
  • The peroneal and posterior tibial arteries can be distinguished from a postero-medial view of the calf with the peroneal laying closest to the shadow of the fibula and the posterior tibial, laying in the muscular tissue
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10
Q

What are important observations to assess the patient ischaemia?

A

• Presence of pedal pulses (posterior tibial and dorsalis paedis) and femoral pulse
• Trophic changes in the feet: Thickened toe nails, dry and hairless skin or the presence of gangrene and cyanosis.
• A history of claudication.
The approximate distance walked before pain commences and where in the leg it is located.
Intermittent claudication is an important clinical feature to identify in patients with exercise related leg pain.

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11
Q

Briefly describe the signs of chronic ischaemia?

A
  • Usually the results of atherosclerosis.
  • Worsens over time
  • Progressing claudication and critical limb ischaemia
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12
Q

Briefly define acute ischaemia?

A
not just a recent and severe onset of claudication or diffuse leg pain. Acute ischemia is defined by the presence of six features which include:
•	Pulselessness
•	Pallor
•	Paraesthesia
•	Paralysis
•	Poikilothermia (Cold)
•	Pain
These features may be present in varying degrees and there is usually a rapid and severe onset of symptoms.
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13
Q

What are the main symptoms and their main cause of chronic ischaemia?

A

Claudication
Critical ischaemia
Caused by atherscleoris
Aneurysm

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14
Q

What is the most common cause of lower limb ischaemia?

A

• Atherosclerosis

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15
Q

How can atherosclerosis cause lower limb ischaemia?

A

• can result in either stenosis or occlusion of any one or more of the lower limb arteries
• may cause extensive lengths of stenosis or multiple stenotic focal lesions.
and aneurysms

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16
Q

What is claudication?

A
  • pain which is experienced during exercise due to loss of blood pressure.
  • Intermittent Claudication is ischemic pain experienced during exercise which is relieved once the patient stops exercising
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17
Q

How is claudication usually described by patients?

A
  • usually described as cramping, tiredness, tightness, aching or pain and only occurs after exercise has begun and does not occur due to prolonged standing or sitting.
  • Claudication is often experienced in the calf, but thigh and buttock claudication can occur with more proximal arterial disease.
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18
Q

What are some causes of claudication?

A
  • usually associated with atherosclerosis
  • may be caused by spinal canal stenosis or by some less common arterial conditions such as entrapment syndrome, adventitial cysts or other conditions which cause stenosis of the arterial supply to the leg
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19
Q

What is critical limb ischaemia?

A
  • occurs when the level of ischemia causes tissue loss in the extremity
  • usually associated with extensive ischemic changes and often with severe claudication and rest pain.
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20
Q

What is rest pain?

A
  • Rest Pain refers specifically to ischemic pain when there is insufficient pressure to adequately supply the leg while at rest (while supine).
  • Rest pain usually occurs in the toes and foot but may at times be experienced in the region of the ankle
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21
Q

What are the characteristic features of rest pain?

A
  • The characteristic features of rest pain are usually experienced while supine and relieved by hanging the leg over the side of the bed.
  • This relief is thought to be due to the increase in hydrostatic pressure which is enough to provide sufficient pressure to perfuse the tissues.
  • Rest pain will be associated with trophic changes in the foot since it results from a severe degree of arterial compromise.
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22
Q

Where are aneurysms in the lower limb usually located?

A

the common femoral and popliteal arteries.
• Aneurysms of the popliteal artery are the most common (after aortic aneurysms), with common femoral artery aneurysms coexisting with about 40% of popliteal aneurysms.

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23
Q

What is a true aneurysm?

A

the arterial wall weakens and dilates as it increases in diameter.

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24
Q

How can aneurysm cause acute ischaemia?

A

• Mural thrombus may also form in the lumen of an aneurysm and release emboli, which can occlude the distal arteries.

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25
Q

What is a false aneurysm or pseudoaneurysm?

A

a collection of arterial blood which ‘leaks’ from an artery and is constrained by the adventitia and fibrous tissue adjacent to its source artery.

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26
Q

What causes a false aneurysm?

A

often result from leakage from a needle puncture which does not seal, but may occur with other causes of trauma of the arterial wall.

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27
Q

What are some risks of a false aneurysm?

A

• A false aneurysm may rupture, thrombose its feeding artery or embolise mural thrombus to occlude the distal arteries.

28
Q

What are two causes of acute ischaemia?

A

embolization and thrombosis

29
Q

How can lower leg emboli occur?

A

• from a proximal source such as the heart, an arterial aneurysm, atherosclerotic ulcer, graft, interventional procedure (Iatrogenic) or from a source which cannot be identified (Paradoxical).

30
Q

How can acute thrombosis occur?

A
  • of an atherosclerotic artery or bypass graft may also cause acute ischemia.
  • In an artery, the sudden formation of thrombus can be associated with an ulcerated or ruptured plaque
  • while a graft may form thrombus associated with a stenosis or from residual valves or fibrous bands.
31
Q

Why is acute thrombosis sometimes difficult to identify?

A

not all occlusive thromboses produce the symptoms of acute occlusion and most patients occlude an artery with continuing symptoms of chronic ischemia.

32
Q

What are some causes of AV fistula/malformation

A
Klippel Trenaunay syndrome
Parkes Webber syndrome
A-V fistula from
- trauma
o	erosion of an aneurysm
o	invasion by neoplasm
o	abscess which results in the fistula formation.
33
Q

Describe Klippel Trenaunay syndrome and its relationship to AVM

A
  • Patients have capillary and venous malformations that can cause limb swelling and varicose veins.
  • The venous and capillary malformations do not disturb the blood flow to the leg and these patients usually have a good prognosis.
34
Q

Describe parkes webber syndrome and its relationship to AVM

A
  • also shows capillary malformation with arterial malformations and may also develop varicose veins.
  • The arterial involvement in this syndrome is associated with greater morbidity from increased limb length, ulceration and pain.
  • The heart may also enlarge with the increased cardiac output associated with the degree of malformation present.
35
Q

Describe AV fistulas and their relationship with AVM

A

• considered to be different from vascular malformations
• fistula formation mostly occurring due to trauma or a related pathology such as
o erosion of an aneurysm
o invasion by neoplasm
o abscess which results in the fistula formation.
• Traumatic formation of AV fistula in the lower limb is usually iatrogenic and results from catheter needle insertion or tributaries of the saphenous vein remaining un-ligated in an in-situ bypass graft
• Biopsy is another cause of fistula formation but not usually in the legs.

36
Q

What are the main causes of non atherosclerotic diseases of the lower limb?

A
  • Inflammatory disease
  • Non inflammatory disease
  • Inherited vascular conditions
  • Congenital and developmental vascular conditions
37
Q

What is Burgers disease?

A
  • (Thrombangitis Obliterans)
  • its principal affect is in the extremities
  • mostly the lower limbs.
  • inflammatory arteritis which initially affects the small distal arteries
38
Q

What are the symptoms of burgers disease?

A

• produces severe symptoms such as
o rest pain
o ulceration
o gangrene in the feet or hands.

39
Q

How does burgers disease appear on ultrasound?

A
  • The disease progresses proximally with tortuosity and segmental occlusion being visible with relatively normal appearing artery segments between.
  • Imaging is used to demonstrate the distribution of arteries affected but the disease is primarily diagnosed and managed clinically.
40
Q

What is fibromuscular dysplasia?

A
  • non inflammatory disease of the arteries
  • may affect the arteries of the lower limbs
  • more commonly identified in the internal carotid and/or renal arteries.
41
Q

What is Marfans syndrome?

A

• inherited syndrome where patients may form aneurysmal dilatation

42
Q

What is Ehlers Danlos syndrome?

A

• produce arteries that are fragile and may haemorrhage with a high degree of fatality.

43
Q

What is Pseudoxanthoma elasticum?

A

• less severe condition which may form non significant stenosis in the mid sized arteries such as the femoral artery.

44
Q

What are some Congenital and developmental vascular conditions ?

A
  • Aortic coarctation
  • stricture of the aorta and may occur in the thoracic or abdominal segments.
  • Adventitial cystic disease
  • an uncommon condition where cyst formation in the adventitia causes a characteristic stenosis or occlusion of the artery to produce symptoms of claudication.
  • Popliteal entrapment
  • results from a number of abnormal anatomical arrangements of the popliteal artery which may cause it to be externally compressed by the surrounding muscles or fibrous tissue to cause a stenosis during certain phases of limb movement during exercise.
45
Q

What are the common types of intervention to correct atherosclerotic lesions?

A

Angioplasty and stenting
Bypass graft
Embolectomy
Endarterectomy

46
Q

What are some common lower limb grafts?

A
o	Femoro-popliteal (Fem-Pop) , Above knee Fem-Pop,
o	Femoro-distal or femoro- tibial,
o	Aorto-bifemoral,
o	aorto-iliac
o	femoral to femoral cross-over
47
Q

What is a proximal or inflow graft?

A
  • Grafts bypassing proximal disease

* such as the aorto-bifemoral or axillo-bifemoral graft

48
Q

What are proximal or inflow grafts made of?

A
  • made of synthetic tube since vein is not considered large enough to cope with the high flow rates
  • typically made of Dacron.
49
Q

What graft material is used for above the knee fem pop bypass?

A

• Synthetic grafts are used for this bypass as they have a higher patency rate than vein.

50
Q

What are Extra anatomic bypass grafts?

A
  • grafts which are positioned outside the normal anatomic region of the arteries being bypassed.
  • This usually occurs in the abdominal or thoracic region when the risk of open surgery is too great.
51
Q

What are Extra anatomic bypass grafts made of and what is their path?

A

• synthetic (usually Dacron) and are typically passed subcutaneously to their destination artery.

52
Q

What are common extra anatomic bypass grafts?

A

• The most common of these grafts are the axillo-bifemoral graft and the femoral-femoral cross-over graft

53
Q

What are distal bypasses usually made of?

A
  • Grafts from arteries above the knee to the popliteal or tibial arteries are usually constructed of vein
  • harvested from the patient at the time of surgery.
  • Although not all grafts below the knee are vein grafts, they are preferred because of their higher patency rates.
54
Q

When are synthetic grafts used distally?

A

• A synthetic graft may be used if there is no suitable vein available or if the length of graft is too long and these are usually made of Poly Tetra Fluro Ethylene (PTFE).

55
Q

What is the the most common bypass graft?

A

• The femoro-popliteal graft below the knee

56
Q

How is a femoro-popliteal graft below the knee constructed?

A

• The vein is anastomosed to the common or superficial femoral artery and passed through the adductor canal to be anastomosed below the knee.

57
Q

What are the two bypass methods used for a a femoro-popliteal graft below the knee?

A

• Two distinct bypass methods are used
o insitu graft
o reversed graft.

58
Q

Describe the differences between the insitu and reversed graft

A
  • The insitu graft mobilises the proximal and distal ends of the vein to anastomose to their respective arteries
  • the reversed graft involves removing the vein and turning it around before placing it back in the leg and forming the anastomoses.
  • Both grafts are commonly performed and have a good record for long term patency.
59
Q

Which veins are most commonly harvested for grafts?

A

the great saphenous vein
but the short saphenous, cephalic and basilic veins can also be harvested to create or extend the length of the graft.
The veins of the lower limb and upper limb are often assessed by ultrasound prior to surgery for size, length and patency.

60
Q

How is an embolus removed from a peripheral artery ?

A
  • using a Fogarty catheter.
  • This catheter is a hollow tube with an inflatable balloon on the end.
  • The catheter is passed through the embolus and then inflated.
  • Withdrawing the catheter with the balloon inflated enables the clot to be removed.
61
Q

Where is endarterectomy used in the leg?

A
  • This can be performed in the common femoral artery and may involve the proximal segment of the superficial femoral or profunda femoris arteries.
  • Like the carotid arteries, a long incision is made and the diseased artery is dissected from the remainder of the arterial wall.
62
Q

A patient presents to her general practitioner with pain in the right calf after playing four holes of golf. The pain decreases with rest but returns after playing two more holes. Describe the physical examination her doctor should perform and any diagnostic tests that should be requested.

A
  • Assess pulses, colour, temperature, region of pain, health of skin, duration of pain, any recent injury, or arthritis of knee (Baker’s cyst).
  • Treadmill exercise testing would determine if there were arterial causes for calf pain, may proceed to ultrasound Doppler to assess level and extent of arterial disease.
63
Q

List the important information you would need to demonstrate during a lower limb Doppler examination.

A
  • peak systolic velocity (PSV);
  • AP diameter;
  • aneurysmal dilation;
  • level and length of stenosis or occlusion;
  • PSV ratio before and at stenosis;
  • spectral broadening; and
  • collateral vessels.
64
Q

List the information you are required to provide on lower limb Doppler worksheet.

A
  • waveform type - triphasic, biphasic, monophasic;
  • plaque drawn at appropriate level;
  • description of plaque - calcific, mixed, hypoechoic;
  • PSV at predetermined levels and any increase;
  • ratios of PSV at stenosis compared with immediately proximal;
  • level of stenosis relative to anatomical landmark and length; and
  • technical quality - any regions unable to be assessed and reason.
65
Q

If the the waveform in the popliteal artery is low velocity and monophasic what does that indicate?

A

The preceding disease thus has had a significant haemodynamic effect.