chronic limb ischaemia Flashcards
what is chronic limb ischaemia?
a peripheral arterial disease that results in a symptomatic reduced blood supply to the limbs
what is the typical cause of chronic limb ischaemia?
atherosclerosis
commonly affecting he lower limbs (but upper limbs and gluteals can also be affected)
what are the risk factors for chronic limb ischaemia?
- smoking
- DM
- hypertension
- hyperlipidaemia
- increasing age
- family history
- obesity and physical inactivity
what are the clinical features of chronic limb ischaemia with increasing severity?
stage 1 = asymptomatic
stage 2 = intermittent claudication
stage 3 = ischaemic rest pain
stage 4 = ulceration or gangrene, or both
(the fontaine classification)
what is intermittent claudication?
due to narrowing or the femoral artery
a cramping-type pain in the calf, thigh, or buttock after walking a fixed distance (the ‘claudication distance’), relieved by rest within minutes.
what is burgers test?
involves lying the patient supine and raising their legs until they go pale and lowering them until the colour returns
the angle at which the limb goes pale is Buergers angle
An angle of less than 20 degrees indicates severe ischaemia
what is critical limb ischaemia?
the advanced form of chronic limb ischaemia
it is
- Ischaemic rest pain for more than 2 weeks, needing opiate analgesia
- presence of ischaemic lesions or gangrene as a result of arterial occlusive disease
- ABPI less than 0.5
what is ankle brachial pressure index (ABPI)?
the ratio of the blood pressure at the ankle to the blood pressure in the upper arm (brachium). Compared to the arm, lower blood pressure in the leg suggests blocked arteries due to peripheral artery disease (PAD)
Any ABPI value >1.2 should be interpreted with caution, as calcification and hardening of the arteries may cause a falsely high ABPI.
how will a patient with chronic limb ischaemia be on examination?
pale and cold limbs
weak/absent pulses
other signs
- hair loss
- skin changes (atrophic skin, ulceration, gangrene)
- thickened nails
what are you differentials for a patient presenting with limb ischaemia symptoms?
- spinal stenosis causing neurogenic claudication. Pain from back radiates to lateral aspect of leg (tensor fascia late), having symptoms of initial movement relieved by sitting, not standing.
- acute limb ischaemia. Clinical features that are less than 14 days duration often presenting within hours.
how is chronic limb ischaemia diagnosed?
clinically
ABPI is used to confirm diagnosis and quantity severity
also need CV risk assessment with BP, blood glucose, lipid profile and ECG
do thrombophilia screen if presenting and <50yrs and without significant risk factors. Also should have homocysteine levels checked.
NB: lower homocysteine levels have been associated with reduced risk of CV events
how is critical limb ischaemia investigated?
investigate with a doppler ultrasound to asses severity and anatomical location of occlusion
can do CT angiography or MR angiography if needed
also need CV risk assessment with BP, blood glucose, lipid profile and ECG
how is chronic limb ischaemia managed medically?
- lifestyle advice
- statin therapy (atorvastatin 80mg OD)
- anti platelet therapy (clopidogrel 75mg OD)
- optimise diabetes control
how are chronic limb ischaemia and critical limb ischaemia managed surgically?
- angioplasty with/without stenting
- bypass grafting usually for diffuse disease in younger patients
- A combination such as surgery to clean a specific lesion allo ng access for angioplasty to another region
- amputations are considered for any patients who unsuitable for revascularisation
what are the complications of chronic limb ischaemia?
can result in
- sepsis secondary to infected gangrene
- acute on chronic ischaemia
- amputation
reduced mobility and quality of life
