Peripheral arterial disease
Definitions
Peripheral arterial disease is a term used to describe a narrowing or occlusion of the peripheral arteries, affecting the blood supply to the lower limbs.
Acute limb ischaemia is a sudden decrease in limb perfusion that threatens limb viability.
In acute limb ischaemia, decreased perfusion and symptoms and signs develop over less than 2 weeks.
Chronic limb ischaemia can present as :
intermittent claudication - diminished circulation leads to pain in the lower limb on walking or exercise that is relieved by rest
critical limb ischaemia - circulation is so severely impaired that there is an imminent risk of limb loss.
Chronic limb-threatening ischaemia - clinical patterns with threatened limb viability related to several factors.
It is characterised by chronic, inadequate tissue perfusion at rest and ischaemic rest pain with or without tissue loss.
Causes and Risk Factors
Main risk factors
smoking
diabetes mellitus
and other typical cardiovascular disease risk factors
Pathology: atherosclerosis which narrows the affected arteries, thereby limits blood flow to the affected limb.
Acute limb ischaemia
sudden reduction in arterial perfusion of the limb, most commonly due to thrombosis within a diseased artery when an atherosclerotic plaque ruptures (80–85%).
Symptoms and Signs
Acute limb ischaemia
sudden onset of leg pain or a sudden deterioration in claudication, associated with a loss of pulses and pallor.
There may be features such as coldness and cyanosis of the limb, or loss of muscular power and sensation (these may be subtle or absent).
Action: emergency assessment by a vascular specialist
Chronic limb ischaemia
progressive development of a cramp-like pain in the calf, thigh, or buttock on walking which is relieved by resting
unexplained foot or leg pain
non-healing wounds on the lower limb
Diagnosis of chronic limb ischaemia is based on the presence of typical clinical features and measurement of the ankle brachial pressure index (ABPI).
Ankle brachial pressure index (ABPI)
The ankle brachial pressure index (ABPI) is the ratio of the highest recorded systolic pressure recorded in the affected leg over the highest recorded systolic pressure in either arm.
Procedure
With the person resting and supine (if possible):
Record systolic blood pressure with an appropriately sized cuff in both arms and in the posterior tibial, dorsalis pedis, and, where possible, peroneal arteries.
Take measurements manually using a 7–10 MHz Doppler probe.
Calculate the index in each leg by dividing the highest ankle pressure by the highest recorded systolic pressure in either arm
An ABPI ratio
<0.9 indicates the presence of peripheral arterial disease
0.5 suggests critical limb ischaemia
>1.4 suggests arterial stiffening (medial arterial calcification) and peripheral arterial disease.
ABPI of this value has a 75% sensitivity and 86% specificity to diagnose lower extremity artery disease (lower in people with diabetes)
An ankle-brachial pressure index (ABPI) of less than 0.9 or more than 1.4 indicates the person has an increased risk of major cardiovascular events.
Management
ALL patients with peripheral arterial disease should be offered clopidogrel as secondary prevention of CVD
If clopidogrel is contraindicated or not tolerated, give low dose aspirin alone.
All patients should be offered atorvastatin 80 mg once a day as secondary prevention of CVD
Management of cardiovascular risk, including advice on smoking cessation if applicable.
Advice on peripheral arterial disease and driving.
Intermittent claudication
Offering a supervised exercise programme
Referral for consideration of angioplasty or bypass surgery if risk factor modification and supervised exercise programme are ineffective.
naftidrofuryl oxalate if supervised exercise has not led to a satisfactory improvement, and the person declines angioplasty/bypass surgery. Review progress after 3–6 months and discontinue naftidrofuryl oxalate if there has been no symptomatic benefit.
Critical limb ischaemia
Urgent referral to a vascular multidisciplinary team.
Management of pain.