Friday, October 02, 2009

말초동맥질환 - 10. PAD(Peripheral Arterial Disease)'s Overview

10. PAD(Peripheral Arterial Disease)'s Overview

Peripheral Arterial Disease (PAD) is also known as atherosclerosis, poor circulation, or hardening of the arteries. Peripheral Arterial Disease (PAD) occurs when plaque builds up in the arteries that carry blood to your head, organs, and limbs. Plaque is made up of fat, cholesterol, calcium, fibrous tissue, and other substances in the blood. When plaque builds up in arteries, the condition is called atherosclerosis. Over time, plaque can harden and narrow the arteries. This limits the flow of oxygen-rich blood to your organs and other parts of your body.

 
PAD usually affects the legs, but also can affect the arteries that carry blood from your heart to your head, arms, kidneys, and stomach. This article focuses on PAD that affects blood flow to the legs.

The illustration shows how PAD can affect arteries in the legs. Figure A shows a normal artery with normal blood flow. The inset image shows a cross-section of the normal artery. Figure B shows an artery with plaque buildup that’s partially blocking blood flow. The inset image shows a cross-section of the narrowed artery.

PAD progresses over time at variable rates in each individual depending on the area of circulation effected and one's health and family history. The signs and symptoms of PAD may not arise until later in life. For many, the outward indications will not appear until the artery has narrowed by 60 percent or more.

One method the body uses to adapt to the narrowed arteries is the development of smaller peripheral arteries that allow blood flow around the narrowed area. This process is known as collateral circulation and may help explain why many can have PAD without feeling any symptoms.

When a piece of cholesterol, calcium or blood clot abruptly breaks from the lining of the artery or a narrowed artery blocks off completely, blood flow will be totally obstructed and the organ supplied by that artery will suffer damage. The organs in PAD most commonly affected and researched are the legs.

Your arteries carry blood rich in oxygen and nutrients from your heart to the rest of your body. When the arteries in your legs become blocked, your legs do not receive enough blood or oxygen, and you may have a condition called peripheral artery disease (PAD), sometimes called leg artery disease.

PAD can cause discomfort or pain when you walk. The pain can occur in your hips, buttocks, thighs, knees, shins, or upper feet. Leg artery disease is considered a type of peripheral arterial disease because it affects the arteries, blood vessels that carry blood away from your heart to your limbs.

You are more likely to develop PAD as you age. One in 3 people age 70 or older has PAD. Smoking or having diabetes increases your chances of developing the disease sooner.

The aorta is the largest artery in your body, and it carries blood pumped out of your heart to the rest of your body. Just beneath your belly button in your abdomen, the aorta splits into the two iliac arteries, which carry blood into each leg.

When the iliac arteries reach your groin, they split again to become the femoral arteries. Many smaller arteries branch from your femoral arteries to take blood down to your toes.

Your arteries are normally smooth and unobstructed on the inside but, as you age, they can become blocked through a process called atherosclerosis, which means hardening of the arteries. As you age, a sticky substance called plaque can build up in the walls of your arteries.

Plaque is made up of cholesterol, calcium, and fibrous tissue. As more plaque builds up, your arteries narrow and stiffen.

Eventually, enough plaque builds up to reduce blood flow to your leg arteries. When this happens, your leg does not receive the oxygen it needs. Physicians call this leg artery disease. You may feel well and still have leg artery disease or sometimes similar blockages in other arteries, such as those leading to the heart or brain.

It is important to treat this disease not only because it may place you at a greater risk for limb loss but also for having a heart attack or stroke.

The severity of PAD depends on when it is detected and any pre-existing health factors; especially smoking, high cholesterol, heart disease or diabetes. In the later stages, leg circulation may be so poor that pain occurs in the toes and feet during periods of inactivity or rest.  This is especially true at night. This is known as rest pain, which usually worsens when the legs are elevated and is often relieved by lowering the legs (due to the effects of gravity on the blood flow).

Critical Limb Ischemia

The most advanced stages of PAD can lead to Critical Limb Ischemia (CLI). Here the legs and feet have such severe blockage that they do not receive the oxygen rich blood required for growth and repair of painful sores and even gangrene (dead tissue). This condition, if left untreated, may require amputation.

Critical Limb Ischemia or CLI is a severe obstruction of the arteries which seriously decreases blood flow to the extremities (hands, feet and legs) and has progressed to the point of severe pain and even skin ulcers or sores. Critical Limb Ischemia (CLI) is often present in individuals with severe peripheral arterial disease (PAD). The pain caused by CLI can wake up an individual at night. This pain, also called "rest pain," can be relieved temporarily by hanging the leg over the bed or getting up to walk around.

CLI is very severe condition of peripheral artery disease (PAD) and needs comprehensive treatment by a vascular surgeon or vascular specialist. This condition will not improve on its own!

Treatment for CLI can be quite complex and individualized, but the overall goal should always be to reduce the pain and improve blood flow to save the leg. A treatment plan will likely include:

Medications: Several medications may be prescribed to prevent further progression of the disease and to reduce the effect of contributing factors such as high blood pressure, high  cholesterol and diabetes, and most certainly to reduce the pain. Medications that prevent clotting or fight infections may also be prescribed.

Smoking Cessation: If you smoke, stop! It may save your leg and your life! Ulcer Care: Treatment will likely include medications and dressings for ulcers.

Surgery or Endovascular Procedures: Surgical or endovascular procedures can be highly successful methods that restore oxygenated blood flow to the areas of skin breakdown. An endovascular procedure consists of a small incision through which a catheter is inserted to where the blockages occur. A balloon may be inflated (angioplasty) or the plaque may be scraped off the artery, or the clot may be removed or broken up (thrombolysis). A wire-reinforced stent may be left in the artery to keep it open.

A bypass graft may be performed in more serious cases. This surgical procedure uses either an artificial tube or one of your veins as a new artery to bring improved blood flow to the needed area. The place where the blood flow is constricted is bypassed. In a few cases, the surgeon may cut open the artery and scrape out the plaque keeping the artery usable. The last recourse would be amputation of a toe, part of the foot, or leg. Amputation occurs in about 25 percent of all CLI patients.

Since treatment depends on the severity of the disease and many individual parameters, it is essential that someone with ulcers, or pain in the legs or feet when walking or at rest, see a vascular specialist as soon as possible. The earlier a diagnosis can be made, the earlier treatment can be started with less serious consequences.