Chronic arterial occlusion due to atherosclerosis. Have rate of cardiovascular mortality >5x.
Prevalence of 2-8/1000 in males and 0.5-2/1000 in females – more common in 6th-7th decade.
Hypertension, elevated lipid levels, diabetes and smoking are major risk factors. Smoking is a greater risk factor for peripheral arterial insufficiency than coronary artery disease.
Clinical features in lower limb:
Asymptomatic in early stages. Atherosclerosis affecting the lower limb presents as a continuum of clinical features.
Gradual onset – often do not seek medical advice for subtle early symptoms; foot is cold and numb; fatigue is common; absent/diminished pulses; dry, scaly skin with dystrophic nails; poor hair growth; muscle atrophy; usually no oedema; intermittent claudication; rest pain and/or ulceration/gangrene if advanced.
Fontaine’s Classification of Chronic Leg Ischaemia:
Stage 1 Asymptomatic
Stage 2 Intermittent claudication
Stage 3 Ischaemic rest pain
Stage 4 Ulceration or gangrene or both
Indications for referral to vascular specialist :
• lifestyle limiting claudication
• any sign of potential critical limb ischaemia, such as foot or limb ulceration, skin changes or gangrene
• an ABI less than 0.50 at rest
• an incompressible ankle artery (systolic pressure > 300 mmHg)
• blood pressure more than 75mmHg higher in ankle than arm
• Risk factor modification (RFM) – exercise; low fat diet; smoking cessation; lipid lowering therapy; control of hypertension; glycaemic control (if have diabetes)
• Exercise builds up collateral circulation and improves the ability of muscle to utilise the oxygen that is available improvement in claudication distance. Regular walking is indicated (30-45 minutes, >3x week for at least 6 months) – should walk as far as possible and stop when close to maximum pain, then resume when pain subsides. Supervised programs can be used that use treadmill control of intensity and duration.
• Cessation of smoking (smoking is very highly correlated with presence and progression stopping can have major impact)
• Control of other modifiable risk factors (eg diabetes, dyslipidaemia, hypertension)
• antiplatelet agents (reduce risk of progression and risks of myocardial infarction and stroke; eg aspirin)
• Pentoxifylline (eg Trental; relaxes smooth muscle, inhibits platelet aggregation, increase deformability of erythrocytes decreasing blood viscosity; only helps 20%)
• Clilostazol (antiplatelet and vasodilating agent; inhibits phosphodiesterase; increases claudication distance; contraindicated in congestive heart failure)
• balloon angioplasty
• surgical bypass
• gene therapy (uses angogenic growth factors to stimulate growth of new blood vessels; showed good results in early experiments and trials)
Importance of foot care:
Minor injuries non-healing wounds, infection, gangrene limb loss
Need education re foot and nail care
Detection of disease by podiatrist