Arterial Disease of the Limbs - Presentation, Investigation & Therapy Flashcards
Name the arteries
How do you examine for the aortic pulse?
Above the umbilicus. Use two hands to feel for pulsation vs expansion
How do you feel for the common femoral artery?
Mid-inguinal point, ½ way between the Anterior Superior Iliac Spine and the pubic symphysis
How do you feel for the popliteal artery?
Use both hands to feel deep in the popliteal fossa – leg relaxed into your hands
How do you find the posterior tibial pulse?
: ½ way between the medial malleolus and the achilles tendon
How do you find the dorsalis pedis pulse?
Lateral to the extensor hallucis longus tendon
What is the cause of CLI (critical limb ischaemia)?
Atherosclerotic disease of the arteries supplying the lower limb
What are the risk factors for CLI?
Male
Age
Smoking
Hypercholesterolaemia
Hypertension
Diabetes
What is stage 1 CLA according to the Fontaine classification?
Stage I: Asymptomatic, incomplete blood vessel obstruction
What is stage 2 CLA according to the Fontaine classification?
Mild claudication pain in limb
Stage IIA: Claudication when walking a distance of greater than 200 meters
Stage IIB: Claudication when walking a distance of less than 200 meters
What is stage 3 CLA according to the Fontaine classification?
Stage III: Rest pain, mostly in the feet
What is stage 4 CLA according to the Fontaine classification?
Stage IV: Necrosis and/or gangrene of the limb
Which leg does claudication usually impact?
Bilateral
What is typical past medical history for CLI?
Other signs of atherosclerosis (MI, Stroke?)
What drug might a CLI patient be taking?
control of diabetes, aspirin?
What is the significance of a CLA patient occupation?
Determines the type of treatment
What are the signs of chronic ischaemia on examination?
Ulceration
Pallor
Hair loss
What should you feel during examination of CLA?
Capillary refill times
Temperature
Pulses
Peripheral sensation (particularly in diabetics)
STARTING AT TOES AND ALWAYS COMPARING SIDES
How do you auscultate for CLA?
Hand held doppler (ultrasound machine)
Listening to the dorsalis pedis and the posterior ribial pulses
What is the ankle brachial pressure index and what does it indicate?
Ratio of ankle pressure over brachial pressure
When exercising should be greater than one since leg muscles need lots of O2 so increased blood flow.
At rest the ration should be around 1 less than 1 indicates obstruction of blood flow
What is the buerger’s test?
Elevate legs - pallor below a 20 degree angle indicates severe ischaemia
Hang feet over the edge of the bed - slow to regain colour, should progress to Dark red colour (hyperaemic sunset foot).
Why does hanging feet over the edge of a bed cause CLI patients’ feet to become hyperaemic?
Normally only 1/3 of the capillaries are open. In CLI all capillaries are open and autoregulation is lost
What is peripheral vascular disease treated the same way as?
Should be managed the same way as those with established CHD
What is best medical therapy?
Antiplatelet
Statin: Inhibits platelet activation and thrombosis, endothelial and inflammation activation, plaque rupture
BP control: Target <140/85
Smoking cessation
Exercise: 150% improvement in walking time – body will develop own collaterals with neo-angiogenesis
Diabetic control: 10% of PAD patients are undiagnosed diabetics. Tight glycaemic control prevents microvascular disease
What type of therapy is best for
- Moderate symptoms
- Severe symptoms
- Critical symptoms
Moderate - BMT only
Severe - BMT, angioplasty/stent, surgical bypass
Critical - BMT, angioplasty / stent / endovascular reconstruction / surgical bypass
What are the possible imaging investigations for CLI?
Duplex (ultrasonography where structure or architecture of the body part is captured and flow or movement of a structure is visualized)
CT/MRA
Digital subtraction angiogram (angiography)
What are the advantages and disadvantages of Duplex?
Advantages:
Dynamic – assess flow as well as anatomy
No radiation/contrast
Disadvantages:
Not good in the abdomen (iliacs)
Operator dependent, time consuming
What are the benefits of CT/MRA
Advantages:
Detailed – allows treatment planning
First line according to NICE
Disadvantages:
Uses Contrast and Radiation
Can overestimate calcification, difficulty in low flow states (difficult if there is terrible heart failure and the contrast can’t really reach the feet)
What are the possible conduits for surgical bypass?
Reversed saphenous vein
What does surgical bypass require?
Inflow
A conduit
Outflow
Why is an autologous conduit better than a synthetic one?
Risk of infection is worse
What are the general risks / complications of surgical bypass?
Bleeding, wound infection, pain, scar, DVT, PE, MI, stroke, death (2%)
What are the technical risks / complications of surgical bypass?
Damage to nearby vein, artery, nerve, distal emboli, graft failure (stenosis, occlusion)
What is reintervention rate for surgical bypass?
18.3 – 38.8% (higher if smoking)
What are 5 year patency rates of surgical bypass?
45-73%
What are the types of amputation from the hip down?
Which type of amputation requires more energy?
BKA or AKA (above or below the knee amputation)
63% higher in BKA
117% higher in AKA
What are the different ways an embolus can arise?
MI, AF, proximal atherosclerosis (not DVT/PE these are linked to venous disease)
Trauma
Dissection
Acute aneurysm thrombosis
What is the point in finding out the onset/duration of symptoms?
Lets you know the likely prognosis
What are the 6 P’s of presentation?
Pain
Pallor
Perishingly cold
Paraesthesia
Paralysis
Pulseless
Compare to contralateral limb
What is compartment syndrome?
Compartment syndrome develops when swelling or bleeding occurs within a compartment. Because the fascia does not stretch, this can cause increased pressure on the capillaries, nerves, and muscles in the compartment. Blood flow to muscle and nerve cells is disrupted. Without a steady supply of oxygen and nutrients, nerve and muscle cells can be damaged.
In this case what causes the acute compartment syndrome?
This may occur after a surgeon repairs a damaged blood vessel that has been blocked for several hours.
Rise in creatine kinase - risk of renal failure since creatine is amssive
What is management of acute limb ischaemia?
ECG, bloods, nil by mouth
Analgesia
Anticoagulate (heparin - allows chance of blood getting through occlusion)
What is management of a salvagable limb in ALI management?
If embolus - embolectomy
If thrombus - Endovascular :mechanincal thrombectomy/thrombolysis or open embolectomy +/- bypass
What type of anaesthetic is used for embolectomy?
General or local
What is the likely cause for ALI?
30% embolic, 60% thrombosis in situ
When does irreversible muscle ischaemia occur?
In 6-8 hours
What is the pathophysiology of diabetic foot disease?
Microvascular peripheral artery disease
Peripheral neuropathy – they lose sensation of their foot – more likely chance of trauma
Mechanical imbalance – lose proprioception and walk differently – pressure points different and now damaged
Susceptibility to infection
How do you ensure footcare of a diabetic?
Always wear shoes
Check fit of footwear
Check pressure points of foot regularly
Prompt and regular woundcare
What is diabetic foot management?
Prevention
Good wound care
Tracking infection (lymphangitis or cellulitis)– consider systemic antibiotics
Investigate for osteomyelitis, gas gangrene, necrotising fasciitis
Revascularisation
Disease is very distal – attempt distal crural angioplasty / stent
Distal bypass
Amputation
