Diabetes, Heart, Stroke | March 4, 2015 | Author: The Super Pharmacist
Peripheral arterial disease or PAD is a form of atherosclerosis that leads to a narrowing or blockage of the arteries in the arms or legs. This narrowing of the arteries makes it more difficult for blood to flow to the extremities. When the tissues need increased blood flow, such as during movement, the narrowed arteries do not allow sufficient blood to reach the extremities. This insufficient blood flow causes pain, called claudication. In many ways, claudication in the arms and legs is similar to angina that occurs in the heart; both sensations are caused by insufficient blood flow to tissues. In severe peripheral arterial disease (also called peripheral artery disease), claudication may occur even at rest.
Classically, the patient with PAD will experience pain during exercise; even an exercise as mild as walking. That pain will go away once the patient rests. This correlates to the time in which the tissues are starved of oxygen-rich blood (pain occurs) and then blood flow is restored (pain goes away). Since older people often feel pain in their legs when they walk due to things such as arthritis or simple joint stiffness, peripheral arterial disease and claudication can be difficult to recognise. Patients tend to associate these feelings with old age and their doctors dismiss the problem as a consequence of aging.
The pain associated with peripheral arterial disease is fundamentally different from other age-related pains of the arms and legs.
Since peripheral arterial disease is caused by atherosclerosis, many of the risk factors for atherosclerosis that occurs in the heart and in the large arteries are the same as those in the smaller blood vessels in the arms and legs. These may include:
Hereditary. Peripheral arterial disease tends to run in families. People who have close relatives with PAD are more likely to develop the condition.
Smokers. Individuals who smoke cigarettes are significantly more likely to develop atherosclerosis and, consequently, peripheral arterial disease. In fact, smoking seems to be a more significant risk factor in PAD that it is in coronary artery disease. In other words, smokers have an even greater likelihood of developing peripheral arterial disease than coronary heart disease (but still have a higher likelihood of developing both diseases than non-smokers).
High blood pressure, diabetes, and abnormal levels of cholesterol are strong risk factors for peripheral arterial disease.
Not all traditional risk factors for atherosclerosis apply to PAD, however. For instance, men and women appear to develop PAD roughly at the same rate, while men tend to develop coronary artery disease in greater numbers than women do, especially at younger ages. In fact, women may be even more likely to develop PAD than men are.
The American College of Cardiology and the American Heart Association have identified several groups of individuals who have a higher prevalence of peripheral arterial disease:
Some basic diagnostic “studies” may occur during physical examination. For example, physicians may be able to detect unusually weak pulses in the arteries of the legs (i.e. pedal pulses). If blood pressure is not the same when it is measured in both arms (a difference of greater than 10 mmHg), this suggests one of the arms may have peripheral arterial disease. In fact, comparing blood pressure measurements of various parts of the body (e.g. ankle versus upper arm, wrist versus upper arm, toes versus upper arm, etc.) can be indicative of the diagnosis of PAD.
When available, physicians may be able to perform a bedside ultrasound study to measure what is called the resting ankle-brachial systolic pressure index or ABI. In other cases, patients may need to go to a diagnostic laboratory for this testing. The clinician uses Doppler ultrasound to carefully measure the systolic blood pressure (the top number in a blood pressure reading) in both the upper arm and the ankle. The two measurements are compared in a simple ratio of ankle blood pressure to brachial blood pressure. An ABI of less than 0.90 is highly indicative of peripheral arterial disease. An ABI of less than 0.4 is usually associated with leg pain at rest and possible tissue damage.
Arteriography, also known as angiography of the arteries, is the gold standard for diagnosing peripheral arterial disease. While arteriography is the gold standard, patients do not always need to use this expensive test if the symptoms, physical diagnosis, and less invasive testing can confirm diagnosis. If arteriography is necessary, the clinician and patient has three choices (if the technology is available in their medical center).
1. The standard approach is to place a thin tube called a cannula into an artery, usually starting in the upper, interior thigh. The cannula is moved to various locations within the blood vessel system and a small amount of radiocontrast dye is released. This dye travels through the arteries showing up on special x-rays called fluoroscopy. The physician can detect areas of narrowing or blockage using this technique.
2. Some advanced medical centers have multi-detector computed tomography, which also requires the use of contrast dye but can provide a rapid diagnosis.
3. The third option is related to an MRI and is called an MRA or magnetic resonance angiography. In an MRA, contrast is injected and an MRI machine is used to create high-resolution images of the blood vessels. All three diagnostic approaches are expensive and again may not be necessary if “low-tech” studies provide the diagnosis.
Treatment for PAD involves a combination of risk factor management, drug treatment, and possibly invasive procedures. Since peripheral arterial disease is progressive, the progression can be halted (and possibly reversed) by lifestyle interventions and atherosclerosis treatment.
Treatments that are not helpful and may be harmful include warfarin, hormone replacement therapy, garlic, vitamin D supplements, and chelation therapy. In severe cases of peripheral arterial disease, surgical treatments may be necessary.
When possible, experts recommend the use of angioplasty and stents in troublesome arteries.
In this treatment, a thin catheter is inserted into an artery in the upper leg and advanced to the site of narrowing or blockage. A balloon is used to expand the artery and then a stent or metal cylinder is deployed that holds the artery open. This stent permits greater blood flow through the diseased artery and reduces symptoms of claudication in the affected extremity.
In the worst cases of PAD, revascularisation surgery may be necessary. This approach is very similar to a CABG (pronounced cabbage) procedure in the heart, also known as a coronary artery bypass graft. An artery or vein is harvested from somewhere in the body and then reconnected before and after a place of arterial narrowing. Blood flows through the transplanted artery in addition to or instead of the original, blocked artery. Arterial surgery is only used when angioplasty and stents are not an option.
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