Peripheral Arterial Disease
Definition
An atherosclerotic process that causes stenosis and occlusion of non-cerebral and non-coronary arteries.
Exclude Red Flag Symptoms
ACUTE LIMB or ACUTE ON CHRONIC LIMB ISCHAEMIA
Acute leg Ischaemia is the diagnosis not to miss in a patient presenting with a painful limb of sudden onset. This can be defined as a leg which has previously been stable (either totally pain free or which has had a consistent claudication distance) which demonstrates a sudden deterioration in the arterial supply over a period of less than 2 weeks.
The classic 6 P’s
Pain – Always present with acute ischaemia
Pulselessness – posterior tibial (ankle) pulse should always be present in a normal limb. A pulse which is suggested to be ‘weak’ or ‘faint’ is actually likely to be not present at all!
Pallor – pale colour compared to other leg. Mottling and cyanosis are late signs of ischaemia.
Perishingly cold – compare to other limb
Paralysis and Paraesthesia – these are late, limb threatening signs.
If suspected measure the ABPI’s with a hand held Doppler
An absent (or very sluggish, monophasic) Doppler signal warrants an emergency admission as the limb will be threatened.
CHRONIC LIMB ISCHAEMIA (CLAUDICATION OR REST PAIN+/-TISSUE LOSS)
Presentation
Claudication – pain on walking after a pain free distance. Try to establish the claudication distance i.e. the distance until the pain appears.
or
Rest pain – pain when at rest. This can be more prominent when in bed as the arterial flow is not aided by gravity. This is a sign of critical (advanced) ischaemia.
+/-
Ulceration/tissue loss – often hairless, shiny limbs with arterial (punched out) ulcers and finally gangrene.
Examination
Limb temperature
Reduced capillary refill- pressing on plantar surface (ball of the foot) is often a clearer test of refill than that in the toes. If >2 seconds then suspect ischaemia.
Buerger’s Sign – loss of colour as the leg is held in a straight leg raise position.
Tissue loss – Any signs of ulceration, necrosis or gangrene.
Palpate pulses – Posterior tibial (PT) and Dorsalis pedis (DP) pulses which are easily palpable makes PAD much less likely as a diagnosis. Feel for popliteal pulse. If this is easily palpable then this is likely to represent an aneurysmal vessel and USS should be obtained to prove this. If pulses are weak or absent then do ABPI’s
Ankle/brachial Pulse Index (ABPI’s) (A Quick guide)
Patient on bed supine
Place sphygmometer cuff around mid-calf.
Use hand held Doppler to find DP or PT pulses
Inflate cuff until pulse disappears and record the pressure.
Measure supine brachial pressure
Divide Ankle pressure by brachial
0.9 - 1 = Normal, arterial disease unlikely
0.5 to 0.9 = claudication likely and risk of tissue loss
<0.5 = critical ischaemia (rest pain/tissue loss)
Management
When to refer
Instigate risk factor modification. Consider referral of patients with claudication which is affecting their quality of life. Most patients will not be managed with re-vascularization but specialist assessment is needed to identify those who would benefit from angioplasty or formal bypass grafting. Exception to this would be patients with stable claudication distances whose quality of life is unaffected.
Refer patients with tissue loss suggestive of arterial cause (ulceration and/or gangrene). Gangrene which is wet in appearance is suggestive of an additional infective process and may well need IV ABx. Exception to referral may be an elderly patient with dry gangrene who is unaffected by its presence.
Risk factor modification
SMOKING cessation is by far the most important single step in management.
EXERCISE is important to increase claudication distance. Suggest walking through the pain for an extra 10 to 20 yrds before rest. This should encourage collateral circulation development. 2 sessions of exercise per week can improve claudication distance by 50 to 200% (Watson et al, 2008)
MEDICATION
Treat hypercholesterolaemia and hypertension aggressively. The CAPRIE study now suggests using clopidogrel as the antiplatelet of choice. Do not use aspirin and clopidogrel together and warfarin is not routinely advised unless another indication is present.
Naftidrofuryl (200mg tds) is a peripheral vasodilator now recommended by NICE for use in primary care for those PAD patients who have not improved with lifestyle measures and who do not want to be referred for angioplasty or surgery. Use should be reviewed in 3 to 6 months and discontinued if symptoms have not improved.
Ramipril (10mg) has been shown recently to increase pain-free walking and distance (JAMA 2013). Previously ACE inhibitors were discouraged in PAD due to the risk of renal artery stenosis. Now its use is encouraged. Monitor renal function closely after starting.
References:
BMJ (2012):345, 4947
CAPRIE (1996): 348, 1329
Watson et al (2008): 4, Cochrane review.
NICE (2012) CG 147
Responsible GP: Dr Mark Pickard
Responsible Consultant: Mr Paddy McCleary
Date published: April 2014. Next review: April 2015
