Sarah May, 61, had trouble walking. Although she is a vivacious and active woman who loves travelling, she could not walk far before her legs would cramp up. Her feet were also constantly cold. But May (real name withheld for patient confidentiality) knew very well what was ailing her.
Fourteen years ago, she had been diagnosed with peripheral arterial disease (PAD), a common circulatory problem in which the blood flow to her legs was reduced because her arteries had been narrowed by a build-up of fatty material - a condition called atherosclerosis.
Atherosclerosis is more commonly known to affect the coronary arteries of the heart and in the brain, where they can cause heart attacks and strokes. However, atherosclerosis is a systemic disease and can also take place in arteries supplying blood to other parts of the body, such as the legs, arms, lungs and kidneys.
In PAD, the reduced blood circulation to the legs can cause painful cramps when walking, leg weakness and numbness, coldness in the feet, poor wound healing, ulcers and even gangrene.
Although PAD is not well known - only 26 per cent of respondents to an American phone survey said they were familiar with the condition - it carries a health risk to patients. One in five PAD patients will suffer death for cardiovascular reasons, experience a heart attack or stroke or require admission to hospital. The risk of death is increased in PAD patients whether they exhibit the symptoms or not.
May had all the classic risk factors for developing PAD - diabetes, hypertension and a smoking habit. In 1996, she underwent a balloon angioplasty - in which a deflated balloon on a catheter was placed into the narrowed arteries in her leg and inflated to widen the constricted area before being removed.