by Maria Adams, MS, MPH
Anatomy and Physiology
Your arteries carry blood from the heart to the organs and tissues throughout your body; your veins return the blood back to the heart. With few exceptions, blood in the arteries is oxygen-rich, while blood in the veins is oxygen-depleted.
Blood to the legs travels from the heart through the main artery called the aorta, which splits into the left and right iliac arteries at about the level of the navel. When they reach the groin, the iliac arteries are renamed the femoral arteries.
The femoral arteries also split at the groin, with one branch going to the thigh, and the major branch traveling down each thigh and behind the knee, where they are renamed the popliteal arteries. From there the arteries divide into three major branches to supply blood to your feet: anterior tibial, posterior tibial, and peroneal arteries.
Reasons for Procedure
Fatty deposits, called atherosclerotic plaques, can build up inside your arteries, narrowing the passageway and interfering with blood flow. This narrowing, called stenosis, most commonly occurs in the aorta, iliac, and femoral arteries. Stenoses that cause insufficient blood flow in the legs can lead to painful muscle cramps in the affected leg while walking, a condition called claudication.
Left untreated, stenosis in the arteries of the lower extremity can cause the circulation to become so poor that an individual experiences constant pain, and other symptoms such as cold feet, open sores,and gangrene.
To diagnose atherosclerosis of the lower extremities and determine where the blockage is, doctors use a number of tests, which may include: comparison of blood pressure in the arms and legs; doppler ultrasound, which uses sound waves to measure blood flow through your arteries; magnetic resonance angiography, or MRA, which uses a powerful magnet, radio waves and computers to produce images of arteries; CT angiography, which uses a CT scanner and dye injected into your vein to produce an image of your arteries without a direct injection into the artery; x-ray angiography, which uses a special dye injected into the arterial blood stream to produce x-ray images of arteries.
Treatment for atherosclerosis of the legs always begins with lifestyle changes, such as: following a low-calorie, low-fat diet, participating in a progressive exercise program, quitting smoking, controlling high blood pressure, managing high cholesterol.
In addition to lifestyle management, medications are often prescribed that can decrease pain during walking or lower the risk of further complications. These include drugs that: interfere with the formation of blood clots, improve the flow of blood through narrowed arteries, control blood pressure, and lower cholesterol.
When lifestyle changes and medications prove insufficient, one of two invasive procedures may be recommended: balloon angioplasty or bypass grafting. In a balloon angioplasty, a balloon-tipped hollow catheter is threaded through the affected artery to the site of the obstruction. Inflating the balloon expands the narrowed area, restoring blood flow. A stent may also be inserted to help keep the artery open after the balloon is withdrawn.
In the other type of procedure, bypass grafting, a surgeon restores blood flow to a leg by using a vein or artificial blood vessel to construct an alternate route around a blockage. In the case of a femoropopliteal bypass graft, for example, a stenosis in the femoral artery is treated by attaching one end of a bypass vessel to the top of the femoral artery above the blockage and the other to the popliteal artery below the blockage.
If the popliteal artery is also affected by atherosclerosis and is too narrow to receive a graft, the lower end of the bypass vessel may be attached to one of the arteries beyond it. If, for example, the anterior tibial artery is used instead, the procedure is called a femoral-tibial bypass graft.
In the days leading up to your procedure: arrange for a ride to and from the hospital and for help at home as you recover. The night before, eat a light meal. Do not eat or drink anything after midnight except for medications that you may be told to take. You may be given antibiotics to take before the procedure to help prevent infection. If you regularly take medications, herbs, or dietary supplements, your doctor may recommend temporarily discontinuing them. Do not start taking any new medications, herbs, or dietary supplements before consulting your doctor.
Before the procedure, an intravenous line will be started. Artery bypass grafts of the lower extremity are usually done under general anesthesia, which will put you to sleep for the duration of the operation. In this case, a breathing tube will be inserted through your mouth and into your windpipe to help you breathe during the operation.
If your procedure is done under regional anesthesia instead, you will remain awake and sedated, but your legs will be numbed. In either method of anesthesia, a catheter will be inserted in your bladder to collect your urine.
All artery bypass procedures of the lower extremities are performed in a similar fashion. The only major difference is that a femoral-tibial bypass generally involves longer vessels and incisions, since the graft attaches further down the leg. The rest of this tutorial will focus on the femoropopliteal bypass procedure.
If possible, your surgeon will use a large vein, usually the saphenous vein, in the same leg to construct the bypass. But in some cases, your surgeon may need to use veins from your other leg, or even from your arms. If necessary, an artificial blood vessel made from a type of Teflon, called PTFE, may be a third option. Your surgeon may decide to perform a preoperative ultrasound to see which vein, if any, will be adequate for use as a bypass channel.
If your saphenous vein, or any other vein, is being used for the graft, your surgeon will make an incision, remove part of the vein, and prepare it for grafting. This will involve tying off the side branches and removing the valves inside to allow the blood to flow smoothly. In some cases it is possible to remove the vein using endoscopic techniques, which requires small incisions at the groin, knee, and calf.
Next, your surgeon will make an incision in the groin area to expose the femoral artery above the obstruction. Your surgeon will make another incision near the inside of the calf to expose the popilteal artery below the obstruction. Your surgeon will temporarily clamp off both arteries to block the flow of blood so that he or she can attach the graft.
Then your surgeon will take the vein to be used for the graft and tunnel it down the leg along the femoral artery, from the groin to the knee. Your surgeon will suture one end of the vein graft into the femoral artery at the groin, and the other end into the popliteal artery at the knee, thereby bypassing the blocked segment.
Your surgeon will then check the graft for leaks, repair them if found, and remove the vascular clamps. This will allow blood to flow through the graft to the lower leg. Finally, your surgeon will close the incisions. In some cases, the saphenous vein may be used as a graft but kept in place; this is known as the "in-situ" technique. In this procedure, your surgeon will remove the valves inside the vein with a small endoscope and cutting instrument, and then attach the upper end of the vein to the femoral artery, and the lower end to the popliteal artery.
Risks and Benefits
Possible complications of femoropopliteal bypass surgery include: excessive bleeding, clotting that causes blockage of bypass graft, blood clots in the legs that may travel to the lungs, nerve injury, kidney failure, surgical wound infection, limb amputation, adverse reaction to general anesthesia, heart attack, or deathPotential benefits of femoropopliteal bypass surgery include: improved blood supply to the leg, increased activity without leg pain, decreased risk of leg ulcers, gangrene, and other complications of arterial stenosis, saving the leg from amputation. In femoropopliteal bypass surgery, or any procedure, you and your doctor must carefully weigh the risks and benefits to determine whether it's the most appropriate treatment choice for you.
After the Procedure
After your procedure, you will be taken to the post-surgical recovery area for close monitoring. If you had general anesthesia, your breathing tube will be removed and you will most likely receive oxygen through a mask for 10-12 hours. You will not be able to eat or drink for 24 hours, but will receive IV fluids along with medications. The medications will control your pain and thin your blood to lower the risk of blood clots.
The usual hospital stay after a femoropopliteal bypass procedure is 5-7 days. It is important to get out of bed as soon as possible following your surgery; by day two or three you should be able to walk with the assistance of a nurse or a walker. You may be discharged home or to a skilled nursing facility for further wound care or physical therapy.
Once you are home, be sure to contact your doctor if you experience: redness, swelling, increasing pain, excessive bleeding, or discharge from the incision sites, signs of infection, such as fever and chills, pain and/or swelling in your feet, calves, or legs, numbness in your leg, or if your leg becomes cool, pale, or blue, shortness of breath, chest pain, or severe nausea or vomiting, decreased urination or bleeding in the urine.
Your leg will remain swollen for 2-3 months. To strengthen your leg and improve healing you should walk every day, gradually increasing the length of your walks. Your doctor may also recommend physical therapy exercises. In addition: It is critical that you do not smoke. Smoking can jeopardize the success of your surgery. You may need to take anticoagulants for several months. In order to decrease swelling, elevate your leg when you are not walking. Do not drive until you are pain free and have full movement. Follow up with your surgeon as advised.