The Mechanism of Claudication

The muscles in the legs, particularly the calf muscles, are exercised during walking, and because of the blockage in the artery or arteries, they are exercised beyond the availability of oxygen to the tissues. The muscles produce lactic acid, which sensitises the nerves, and is experienced as pain.

When the person stops and rests, the lactic acid is washed out of the muscles, and the pain is relieved.

Lactic acid is a potent vasodilator (it opens up the blood vessels) and helps in the process of building up collaterals.

If a good collateral circulation develops, the claudication may improve, unless the blood supply to the lower limb becomes increasingly obstructed.

The claudication distance may vary from rest, to 30 metres to several hundred metres. It is very variable, and depends on the expectations of the person in question and his/her lifestyle/habits.

Claudication Distances and Severity of Disease

• 200 metres
  Significant restriction – encourage exercise no intervention at this stage. Monitor.
• 100 metres
  Life- altering, as it affects activities such as shopping (retired people) or work activities. Intervene. Angioplasty but not by-pass.
• 50 metres
  Far more severe. Perform investigations. Angioplasty.
• Rest Pain
  Will progress to gangrene or loss of limb, unless lifestyle changes are undertaken (stop smoking, lower cholesterol, increase walking, treat diabetes adequately, treat hypertension).

Amended April 2008