FitFab Club interviewed Dr Benjamin Chua from the Vascular Interventional Centre to learn the risk factors and symptoms associated with Peripheral Artery Disease (PAD) as well as find out why PAD rates are on the rise in Asia. This is the first part of a two-part article.
Q: What is peripheral artery disease (PAD)
PAD is the third most common clinical manifestation of atherosclerosis after coronary artery disease (CAD) and stroke but there is much less awareness and understanding of the disease among the general public. It is characterised by debilitating atherosclerotic occlusion (blockage) of peripheral (away from the heart) arteries, most commonly in the lower extremities. The disease can be asymptomatic or accompanied by symptoms, such as cramping, leg pain, critical limb ischaemia (reduced blood flow to the extremities caused by severe obstruction of the arteries), and occasionally acute limb ischaemia (a sudden lack of blood flow to a limb caused by embolism or thrombosis).
The majority of cases in the Asian population present with critical ischaemia with tissue loss i.e. non-healing foot ulcers or gangrene of toe(s). A much smaller number present with vascular clarification pain i.e. pain in the calf or thigh when walking or exercising. PAD is associated with a significantly increased risk of heart attack and stroke.
Q: What are the causes and risk factors of PAD?
Risk factors that contribute are similar to those for CAD, they are diabetes, smoking, ageing, obesity, high blood pressure, high cholesterol, family history of heart disease, and excess levels of C-reactive protein or homocysteine. The most significant risk factor in Asia is diabetes. The rise in PAD rates is in tandem with the rising incidence of diabetes across Asia, Singapore included.
Q: Who is at most at risk of developing PAD?
I would say diabetics with poorly controlled blood glucose levels, smokers, patients with a history of coronary heart disease (high cholesterol, hypertension), patients with kidney failure. The risk of developing PAD also increases as we age, with men prone to developing it in their 50s or 60s and women a decade or so later. The more risk factors you have the higher your personal risk.
Q: PAD is on the rise across the world but in some regions, including Asia, it is rising faster than others; what factors create those differences?
There are usually a variety of contributing factors when we observe an increasing incidence of a disease and the significance of any individual factor may vary from region to region or country to country. However, the main drivers are the rising incidence of diabetes and atherosclerosis, which in turn are driven by obesity and smoking. Ageing populations also play a role.
For instance, the causes of the increase in PAD in Japan and Singapore are likely to be linked to their rapidly ageing populations; although in Singapore obesity and hence diabetes also play a significant role. The other two countries have two of the youngest populations in Asia so the risk factors there will be different. In Indonesia smoking is much more prevalent; 76% of men smoke there compared to 28% in Singapore. In the Philippines the driver might be obesity; according to their Food and Nutrition Research Institute (FNRI), the percentage of the population that is obese has doubled in 30 years and the prevalence of obesity in the country is now 31.1% leading to a rise in diabetes too.
Q: PAD seems to be occurring in a younger demographic across South East Asia than in some other regions like Europe and the Americas, how does Singapore compare?
In Singapore, the main driver of the increase in PAD among younger people is the rise in obesity and diabetes but we are also seeing a rise due to our ageing population. The over 80 age group is the fastest growing demographic in Singapore having almost doubled in number over the past decade.
Q: Are there symptoms people should look out for?
Many people with PAD have mild or no symptoms, especially in the early stages. Some people have pain or cramping in their limbs, most commonly the lower leg when walking and climbing stairs. The pain usually disappears after a few minutes’ rest. In advanced PAD pain may occur even when sitting or lying down, this is called ischaemic rest pain.
The severity of pain varies widely, from mild discomfort to debilitating pain. The location of the pain depends on the location of the clogged or narrowed artery. Pain and cramps in the calf are the most common.
Other symptoms and signs of PAD include:
- Painful cramping in one or both hips, thighs or calf muscles after certain activities.
- Numbness or weakness in the legs
- The affected leg or foot often feels cold, especially when compared with the opposite foot
- Sores and ulcers on the toes, feet or legs that don’t heal properly/ completely. Critical ischemia can lead to gangrene of the toe(s)
- The foot or lower leg turning blue or purple
- Losing hair or slower hair growth on the feet and lower legs
- Slower toenail growth
- Patches of shiny skin on the legs
- No pulse or a weak pulse in the lower legs or feet
- Erectile dysfunction in men
Dr Chua is a Senior Consultant Vascular Surgeon, and the Medical Director of the Vascular & Interventional Centre at Farrer Park Medical Centre.