Peripheral artery disease (PAD)
Peripheral arterial disease (PAD) is narrowing (stenosis ) in the arteries of the legs caused by atherosclerosis.
The earliest sign of PAD is leg pain with walking that is improved immediately upon rest (claudication). Typically the pain is described as a deep muscular ache or weakness that involves the muscle of the back of the calf or less commonly, the thigh. The pain arises only after walking a certain distance, and dissipates after standing still a few minutes. It comes on more readily when walking at a fast pace or when walking up hill. Most people do not develop the same pain with other forms of exercise, such as climbing stairs, riding a bike, or swimming. Other conditions can cause leg pain that should not be confused with claudication. Sciatica (pinched nerve in the back) causes a stinging or burning pain that shoots down the back of the leg from the back or buttock area. Sciatica pain, unlike claudication, can arise from standing or sitting too long and usually takes a long time to dissipate. Arthritis pain can also be mistaken for claudication, but arthritis involves the joints, not the muscle of the leg and arthritis pain typically is worst when you first start an exercise and seems to improve as you continue that exercise.
About a third of people who have PAD develop such severe limitation in blood flow to the leg that they are likely to lose the leg if blood flow is not restored. We call this limb threatening ischemia, and it may be associated with chronic non-healing wounds, gangrene (dead tissue) or rest pain (pain in the foot or lower leg that wakes you from sleep).
PAD is a manifestation of atherosclerosis, so being diagnosed with PAD increases the likelihood of your having heart disease or carotid stenosis. Frequently, you doctor will recommend screening for these other problems if you are found to have PAD. Treating PAD begins with controlling risk factors for atherosclerosis.
PAD is fairly common; in random screening, 10-20% of people over the age of 65 have PAD. An estimated 12 million people in the U.S have PAD-- that's more than the number of people with cancer or Alzheimers disease. Yet over 75% of adults don't know what PAD is. This disease is underdiagnosed; almost 30% of people with PAD are unaware they have it.
Screening is performed by checking pulses in the legs and performing an ankle-brachial index (ABI). The ABI is a ratio of the blood pressure in the leg to the blood pressure in the arm. It is normal when the pressures are equal. If the blood pressure in the leg is lower than in the arm, the ABI abnormal. Ultrasound or CT can be used to locate the region of stenosis or occlusion.
Angioplasty is used to treat narrowings (stenoses) in arteries related to atherosclerosis. Through a needle stick in the groin, a small tube (catheter) is inserted into the artery. Contrast dye is injected under continous x ray (fluoroscopy) to outline the areas of stenosis. A wire and balloon catheter are negotiated past the region of blockage and used to dilate the artery from the inside, literally "cracking" the plaque and expanding the vessel to increase the channel blood takes through the artery. In some cases, we use special "cutting balloons" to score the plaque; other times we use freezing balloons (cryoplasty) to treat the plaque or we deploy a metal tube (stent or stent graft) to help keep the artery open. Which technique is used depends on the particular look of the plaque.
Angioplasty can be performed under a local anesthetic with sedation. It is done in the operating room or fluoroscopy suite. Generally patients can be discharged the same day, after a period of bedrest to heal the puncture site. If we are successful at angioplasty, most people are advised to take plavix or another blood thinner for a period of time afterwards. This helps to keep the newly treated artery open.
Often, if the artery is completely blocked, we do not know ahead of time whether we will be successful with an angioplasty. Sometimes we cannot re-open the artery and we must consider other methods (like bypass). The advantage to angioplasty is that it is minimally invasive and healing time after the procedure is generally very brief. The disadvantage is that angioplasty may not last as long as bypass surgery. Re-narrowing of the artery (restenosis) is not uncommon over time. Maintaining good control of risk factors (watching the blood pressure and cholesterol, managing diabetes, not smoking) maximizes chances of long term success after angioplasty.
After angioplasty, patients are encouraged to be active, but to avoid heavy lifting or straining for a week. Risks of angioplasty include puncture site complications, bleeding or bruising, downstream embolization.
A bypass is a surgery used to treat blockages in arteries or arterial aneurysms. A tube (graft) is tunneled through the leg and sewn into the artery above the blockage and the artery below the blockage, to create a detour around the occluded segment. Usually this is achieved through 2 or 3 small incisions in the leg. Sometimes we use the patient's own vein as the bypass, other times we use a synthetic graft made of Goretex.
A bypass usually takes 2-3 hours. It is performed under a light general anesthetic or a spinal anesthetic. Generally patients stay in the hospital a day or two after surgery. Most people take aspirin after the procedure; other patients are advised to take plavix or another blood thinner. This helps to keep the bypass open. Maintaining good control of risk factors (watching the blood pressure and cholesterol, managing diabetes, not smoking) maximizes chances of long term success after bypass surgery. Bypass generally is associated with better long term outcomes than angioplasty, but bypass is a more invasive procedure.
After angioplasty, patients are encouraged to be active, but to avoid heavy lifting or straining for a week. We anticipate some bruising, stiffness and some leg swelling after surgery. Risks of bypass surgery include heart or lung issues, bleeding, infection, wound healing issues, chronic swelling, numbness. After surgery, patients are monitored with surveillance ultrasound scans, which help to detect any re-narrowings in the arteries or in the bypass and help to ensure that the bypass stays open.