MEDICAL MATTERS: When I was a boy, my family used to visit a wealthy elderly woman who lived in an apartment on the top of a famous, long-demolished Dublin hotel. She had an artificial leg which she would detach and wave over her head like a sword, much to the amusement and consternation of us children.
In retrospect, this was my first clinical encounter with peripheral arterial disease (Pad). Our friend was overweight, smoked, and possibly had diabetes and hypertension, some of the major factors involved in Pad, so it was not surprising she had her leg amputated.
Occlusive arterial disease anywhere in the body results from damage to the inner lining of the arteries, which become inflamed and irregular, and are subject to the deposition of plaque formation, often made of cholesterol. The arteries become narrow and may become completely occluded. When this happens, gangrene and amputation is almost inevitable.
Pad should not be viewed in isolation. If the circulation in your legs is compromised, the chances are that you may also have problems with your coronary, cerebral and renal blood flow with all the implications of potentially fatal damage to these organs. Up to 30 per cent of patients with Pad will be dead within five years.
The classic symptom of Pad is intermittent claudication. Walking with impaired circulation will induce a cramp-like pain in the calves which is relieved by rest so that a patient will typically walk in a stop-start pattern. Vague leg tiredness, erectile dysfunction, angina pectoris and poor circulation elsewhere can also imply Pad.
Pulses below the groin may be weak or impalpable. The skin may be mottled or pale and when the limb is lowered after being elevated, refilling with blood will be very slow. A simple but accurate test known as the ankle-brachial systolic blood pressure index (ABI) can be carried out in general practice using a standard blood pressure device and a small Doppler ultrasound machine. Normally the blood pressure in the leg is equal to, or slightly higher, than the arm pressure. An ABI of more than 0.95 is considered normal, whereas a ratio of less than 0.5 suggests severe Pad.
The extent of vascular disease can be assessedby a radiological technique known as magnetic resonance angiography which provides accurate three-dimensional images of the damage.
The risks of developing Pad include being male, getting older, smoking, diabetes, obesity, poorly controlled high blood pressure and high blood cholesterol. You can do nothing about the first two, and as for the rest it’s a case of damage limitation – appropriate attention to the contributory diseases and lifestyle changes.
Giving up smoking is vital. This is difficult and many doctors have anecdotal evidence of smokers who persist with the habit even as bits of their lower limbs progressively disappear.
Diabetics, in particular, must be scrupulous in foot care and even cutting toenails can lead to extensive tissue damage if carried out carelessly.
Drug treatment is of limited value. So-called "vasodilators" are of little use as damaged, rigid, narrowed arteries will generally not respond to these drugs. Statins, used to lower cholesterol, have an anti-inflammatory effect and are often used in patients with Pad, as are aspirin and clopidogrel, agents which thin the blood and reduce the chances of thrombosis. Bypass
surgery is possible and quite successful if blockage is localised but, within five years, 4 per cent of those with Pad will undergo amputations of varying extent.
Exercise is vital and is often underestimated. Regular exercise can increase the claudication distance, help to lower cholesterol and improve general cardiac fitness. Treatment of Pad can be summed up in five simple words which headed a
British Medical Journal editorial some years ago: Stop smoking and keep walking. I am sure my leg-waving friend of yore did neither.
Dr Charles Daly is a GP in CoWaterford.
- Dr Muiris Houston is on leave