People with diabetes are affected by gangrene of the feet at a rate that is 30 times higher than the unaffected population. Many of these severe complications are irreversible. Causes
Risk factor
Factors contributing to increased risk of PAD are the same as those for atherosclerosis. These include age, sex, and ethnicity. PAD is two times as common in males as females. In terms of ethnicity, PAD is more common in people of color compared to the white population in a 2:1 ratio. The factors with the greatest risk association are hyperlipidemia, hypertension, diabetes mellitus, chronic kidney disease, and smoking. Presenting three of these factors or more increases the risk of developing PAD ten-fold. Smoking – tobacco use in any form is the single greatest risk factor of peripheral artery disease internationally. Smokers have up to a 10-fold increase in risk of PAD in a dose-response relationship. Exposure to second-hand smoke has also been shown to promote changes in the lining of blood vessels (endothelium), which can lead to atherosclerosis. Smokers are 2–3 times more likely to have lower extremity PAD than coronary artery disease. Greater than 80%-90% of patients with lower extremity peripheral arterial disease are current or former smokers. The risk of PAD increases with the number of cigarettes smoked per day and the number of years smoked. High blood sugar – Diabetes mellitus is shown to increase risk of PAD by 2–4 fold. It does this by causing endothelial and smooth-muscle cell dysfunction in peripheral arteries.
A decrease in ABI of 15%–20% would be diagnostic of PAD.If ABIs are abnormal, the next step is generally a lower limb Doppler ultrasound to look at the site of obstruction and extent of atherosclerosis. Other imaging can be performed by angiography, where a catheter is inserted into the common femoral artery and selectively guided to the artery in question. While injecting a radio-dense contrast agent, an X-ray is taken. Any blood flow-limiting blockage found in the X-ray can be identified and treated by procedures including atherectomy, angioplasty, or stenting. Contrast angiography is the most readily available and widely used imaging technique. Modern computerized tomography (CT) scanners provide direct imaging of the arterial system as an alternative to angiography.Magnetic resonance angiography (MRA) is a noninvasive diagnostic procedure that uses a combination of a large magnet, radio frequencies, and a computer to produce detailed images of blood vessels inside the body. The advantages of MRA include its safety and ability to provide high-resolution, three-dimensional imaging of the entire abdomen, pelvis and lower extremities in one sitting. Classification
The two most commonly used methods to classify peripheral artery disease are the Fontaine and the Rutherford systems of classification.