Peripheral arterial disease Flashcards
What are the 3 main peripheral arterial diseases?
Chronic ischaemia
Acute ischaemia
Diabetic foot disease
The aorta splits into the ____
Common iliac arteries
The common iliac arteries split into the _____
Internal & external iliac arteries
The external iliac artery becomes the ______
Common femoral artery
What artery branches off the common femoral artery?
Profunda femoris
The common femoral artery eventually becomes the _______
Superficial femoral artery
At the level of the knee, the superficial femoral artery has become the ______
Popliteal artery
What three main arteries continue from the popliteal artery?
Posterior tibial artery - to the ankle
Peroneal artery
Anterior tibial artery:
- Becomes the Dorsalis pedis - to the foot
What are the 5 palpable arterial pulses on the abdomen/lower limbs?
Aorta
Common femoral
Popliteal
Posterior tibial
Dorsalis pedis
Describe how to palpate the aortic pulse
Above the umbilicus. Use two hands to feel for pulsation vs. aortic expansion
Describe how to palpate the common femoral pulse
Mid-inguinal point, half way between the Anterior Superior Iliac Spine and the pubic symphysis
Describe how to palpate the popliteal pulse
Use both hands to feel deep in the popliteal fossa – leg relaxed into your hands
Popliteal fossa = back of knee
Describe how to palpate the Posterior tibial pulse
half way between the medial malleolus and the Achilles tendon
Describe how to palpate the Dorsalis pedis pulse
Lateral to the extensor hallucis longus tendon
tendon to your big toe
What causes Chronic limb ischaemia?
Atherosclerotic disease of the arteries supplying the lower limb
Less commonly:
- Vasculitis
- Buerger’s disease
Blockage of blood flow to parts of lower limb
List the risk factors for chronic limb ischaemia
Male
Elderly
Smoker
Hypercholesterolaemia
Diabetes
Hypertension
Describe the progression/development of an atheromatous plaque
Initial lesion
Fatty streak
Intermediate lesion
Atheroma
Fibroatheroma
Complicated atheroma
How are the symptoms of CLI classified?
Fontaine Classification
Stage 1 - 4
Describe the features of stage I CLI
Asymptomatic
Blood vessel is not obstructed
Describe the features of stage II CLI
Mild claudication pain in limb
Stage IIA = After walking over 200 metres
Stage IIB = Less than 200m before pain
What are the main features of Stage III CLI?
Rest pain, mostly in feet
What are the main features of Stage IV CLI?
Necrosis and/or gangrene
In a clinical examination:
What signs on inspection would indicate chronic limb ischaemia?
Expose both legs:
Ulceration
Pallor
Hair loss
^signs of Chronic ischaemia
In a clinical examination:
What things should you palpate/feel when looking for chronic limb ischaemia?
Temperature
Capillary refill time
Peripheral sensation
Pulses – start at the aorta
In a clinical examination:
Describe the auscultation process for CLI investigation
Using hand held doppler:
Auscultate the Dorsalis pedis & posterior tibial pulses
What special examinations could be carried out to investigate CLI?
Ankle brachial pressure index
Buerger’s disease test
What does the ankle brachial pressure index tell you?
Ratio of AP:BP
Score of 1 or more is all good
The closer the score to 0, the worse:
- Gangrene gives a score < 0.2
How and why do we carry out the Buerger’s disease test?
Buerger’s disease is a less common cause of CLI
Elevate the legs:
- Pallor
- If Buerger’s ankle shows at < 20 degrees elevation then patient has severe CLI
Hang feet over edge of bed:
- Dark red colour (which appears slowly)
Imaging is a key investigative technique for CLI
What types of imaging can be used?
Duplex
CTA / MRA
Digital subtraction angiography
Why is Duplex imaging used to investigate CLI?
- Dynamic
- No radiation or contrast
However:
- Not good for imaging abdomen
- Operator dependant
- Time consuming
Why is CTA / MRA used to investigate CLI?
CT angio / Magnetic resonance imaging
- Detailed image
- Diagnostic (NICE)
However:
- Contrasts & radiation
- Can overestimate calcification
- Contrast is difficult to use in low flow states
What medications are prescribed to those with CLI?
Anti-platelet - Clopidogrel or Aspirin
Statin
Why are Statins prescribed to people with CLI?
Inhibits platelet activation and thrombosis, endothelial and inflammation activation, plaque rupture
What are the main risk factors that are controlled in order to manage CLI?
Smoking cessation
If hypertensive - aim to reduce BP < 140/85
If diabetic - tight glycaemic control to prevent microvascular disease
Aside from medication and measures to control risk factors, what else is used to manage CLI?
Exercise
If medication etc does not work, and a patient’s CLI is continuing to worsen
What is the next ‘step’ in their medical treatment?
Revascularisation surgery or amputation
What are the types of ravscularisation surgeries?
Open surgery:
- Bypass and/or endartorectomy
Endovascular:
- Balloon angioplasty
- Stent placement
- Atherectomy
What is an angioplasty?
Using a weird ballon stick catheter thing you insert into vasculature and go to site of atheroma
Balloon has stent around it
Balloon expands & compresses the atheroma
Stent remains and compresses the plaque
Some stents have drugs imbedded in them to do spicy things
In order for surgical bypass to be possible, what is required?
Inflow
Suitable conduit
Outflow
What can be used as a conduit?
Can either be autologus - ie a vein from the arm or leg
or can be synthetic - PTFE/Dacron (no idea)
What are the risks of surgical bypass?
General - all the usual ones like infection, DVT etc
Technical - Damage to nearby vein, artery, nerve, distal emboli, graft failure (stenosis, occlusion)
Often requires re-intervention 18-40%
The BASIL trial compared the benefits and faults of Angioplasty & surgery for CLI
What was the basic conclusion?
If short term results are what matters - Angioplasty is preferred
However, if the patient has a reasonable life expectancy and is suitable for surgery - then surgery is better
- Surgery has high short term morbidity but is more durable in the long term than angioplasty which is more of a ‘short term fix’
What is Acute limb ischaemia?
Blockage of blood flow to area of leg causes by either a thrombus or an embolus from a proximal artery
Emergency situation
30% embolic, 60% thrombosis in situ
Describe the causes/pathophysiology of ALI
Arterial embolus: 30%
- MI
- AF
- Proximal atherosclerosis
Thrombosis: 60%
- usually of previously diseased artery
Trauma
Dissection
Acute aneurysm thrombosis
What are the 6 P’s of ALI
Pain Pallor Pulse deficit Paraesthesia - pins and needles Paresis/paralysis Poikilothermia (cold)
Compare legs
ALI can cause compartment syndrome
What is this, and why is it bad?
What blood marker is present?
Ischaemia of muscle compartment which is irreversible after 6-8 hours
Characterised by:
- Tense but tender calve muscle
- Inflammation, oedema & venous obstruction
- Rise in creatine kinase
Risk of renal failure - myoglobulinaemia
If an episode of ALI causes too much damage for a limb to be salvageable, what are the potential courses of action for the patients care?
If amputation is beneficial and the patient is willing, then amputate ischaemic limb
If disease is too bad for amputation to save patient, or patient does not want to be amputated then palliate
A patient has Acute limb ischaemia, but the ischaemic limb is salvageable, what is the course of action?
If suspicion of ONLY embolus:
- embolectomy
If suspicion of thrombosis in situ (not embolised):
- Either endovascular or open surgery
What endovascular procedures can be used to ALI?
Mechanical thrombectomy / thrombolysis
Only if patient has thrombosis in situ
What open surgical procedures are carried out to treat acute limb ischaemia?
Open embolectomy +/- bypass
Only for patients with thombosis in situ
What happens in an embolectomy?
Incision into artery and wire thing with small balloon at end passed in
Wire pushed through embolus and balloon inflated on other side
Wire used to pull/guide embolus out through the incision
What is the peri-operative mortality rate for Acute limb ischaemia?
22%
How common is it for someone with diabetes to get a diabetic foot ulcer?
25% of diabetic patients will get a foot ulcer in their lifetime
What are the risks to patients of getting a Diabetic foot ulcer?
50% of foot ulcers get infected & 20% require amputation
What are the potential causes of Diabetic foot disease?
Microvascular peripheral artery disease Peripheral neuropathy Mechanical imbalance Foot deformity Minor trauma Susceptibility to infection
If a diabetic person injures their foot & it becomes infected, how are they treated?
What complications are investigated?
Systemic antibiotics
Investigations for:
- Osteomyelitis
- Gas gangrene
- Necrotising fasciitis
What is the treatment route for someone who has serious, complicated Diabetic foot disease?
Revascularisation:
- Attempt distal crural angioplasty / stent
- Distal bypass
If this^ doesn’t work:
- Amputate
What adjunctive/less immediate management can be used for Diabetic foot disease?
Diligent wound dressing to avoid further infection
Debridement - larval therapy
Negative pressure wound closure
Skin grafts
