What are peripheral aneurysms?
When a weak area of a blood vessel expands or bulges significantly, physicians call it an aneurysm. Most aneurysms occur in the aorta, your body's largest artery. The aorta carries blood away from your heart to the rest of your body. The part of your aorta located in your chest is called the thoracic aorta, and when your aorta reaches your abdomen, it is called the abdominal aorta.
Peripheral aneurysms affect the arteries other than the aorta. Most peripheral aneurysms occur in the popliteal artery, which runs down the back of your lower thigh and knee. Less commonly, peripheral aneurysms also develop in the femoral artery in your groin, the carotid artery in your neck, or sometimes the arteries in your arms. A special type of peripheral aneurysm that forms in the arteries feeding the kidneys or the bowel is called a visceral aneurysm.
If you have a peripheral aneurysm in one leg, you are more likely to have an aneurysm in the other leg. You also have a greater chance of having an aortic aneurysm.
Aortic aneurysms can cause serious complications because they can burst or rupture. Peripheral aneurysms do not rupture as often as aortic aneurysms, although they can do so. However, peripheral aneurysms more commonly can form clots that may block blood flow to your limbs or brain. Peripheral aneurysms, especially if they are large, can also compress a nearby nerve or vein and cause pain, numbness, or swelling.
What are the symptoms?
You may not feel symptoms with a peripheral aneurysm, especially if it is small. Two out of 3 patients with a peripheral aneurysm may not notice any symptoms.
If you do have symptoms, the warning signs will depend on the location and size of your aneurysm. Possible symptoms include:
- A pulsating lump that you can feel
- Leg or arm pain or cramping with exercise, called claudication
- Leg or arm pain with rest
- Painful sores or ulcerations involving the toes or fingers
- Radiating pain or numbness in your leg or arm, which is caused by nerve compression
- Gangrene, or tissue death, which results from a severe blockage in your limb and usually requires some form of amputation
If the carotid artery is involved, the symptoms can include transient ischemic attacks (TIA) or stroke. These are described in the sections on carotid or cerebrovascular disease. If the bowel arteries are involved, the symptoms can be similar to those for mesenteric ischemia and are described in the section on mesenteric ischemia.
What causes peripheral aneurysms?
Peripheral aneurysms may be caused by infection or injury in unusual circumstances, but the actual cause of most peripheral aneurysms is not known with certainty. Researchers believe that atherosclerosis, also called “hardening of the arteries,” is associated with many peripheral aneurysms. Your arteries are normally smooth and unobstructed on the inside but, as you age, they can become blocked through atherosclerosis. In atherosclerosis, a sticky substance called plaque builds up in the walls of your arteries. Over time, your arteries narrow, stiffen, and possibly weaken. Factors that increase your risk for atherosclerosis include:
- High blood pressure
- High cholesterol
- Having a family history of heart or vascular disease
Your risk of developing peripheral aneurysms also increases as you age. People are usually in their 60s and 70s when they are found to have peripheral aneurysms.
What tests will I need?
First your physician will usually ask questions about your general health, medical history, and symptoms. In addition, your physician conducts a physical examination. Together these events are known as a patient history and exam. As part of your history and exam, your physician may check for an aneurysm in your groin or thigh.
If your physician suspects you have a peripheral aneurysm, he or she may order an ultrasound or other imaging test, such as a computed tomography (CT) or magnetic resonance imaging (MRI) scan to confirm it. Angiography, which is more invasive, may be required in some circumstances to plan surgery or deliver medications if this is required.
It is known that many patients who have a peripheral aneurysm also have heart disease. Before performing surgery to treat your peripheral aneurysm, your physician may order tests to check on your heart, such as an electrocardiogram (ECG) or stress test.
How are peripheral aneurysms treated?
Your treatment will depend on the location of your aneurysm, the size of your aneurysm, your symptoms, and whether or not the aneurysm is completely blocked by clots at the time of its discovery. For example, if you have a popliteal aneurysm that is blocked and yet you are having no symptoms, you may not need surgery. In that situation, for example, your physician may recommend that you:
- Control your risk factors for atherosclerosis
- Walk regularly to keep blood flowing in your leg arteries
- Do not cross your legs or squat
- Practice foot care by cleansing your feet regularly and watching out for sores that don't heal (a sign of poor circulation)
Although a popliteal aneurysm that is not blocked may rarely burst, more often it can suddenly become blocked without warning and obstruct the flow of blood to the lower leg. It can also be a source for clots or other debris to break off from inside the aneurysm and travel down the leg arteries to lodge and obstruct blood flow into the foot. Each of these developments can lead to pain and ulceration and, potentially, to amputation of the limb. As a result, if you have a popliteal or femoral aneurysm that is still open, you will need repair of the aneurysm. This is usually done with open surgery but endovascular treatment may be an option in some circumstances. Arm or carotid aneurysms have similar behavior but the symptoms they cause will involve the hand, with pain or ulcer formation, or the brain, with stroke or transient neurological symptoms, respectively.
Vascular surgeons usually treat peripheral aneurysms with a surgical bypass or replacement. During this operation, your vascular surgeon constructs a new pathway for blood to flow by using a graft. A bypass graft may be made from a portion of one of your veins or sometimes a man-made tube, formed from plastic or other materials, that your surgeon connects above and below the aneurysm to allow blood to pass around it. If you need bypass surgery, you will receive regional or general anesthesia. Following the surgery, depending upon the location of your aneurysm, you may need to stay in the hospital for 2 to 7 days.
In some circumstances, if a peripheral aneurysm is blocked by a clot, medications known as thrombolytic agents may be used to dissolve the clots in preparation for bypass surgery. This procedure is sometimes done at the time of angiography, if needed.
The use of endovascular therapy, such as stent grafts, for the treatment of peripheral aneurysms is still in the investigational stages. Nevertheless, endovascular therapy may have a role in the treatment of some patients with peripheral aneurysms, especially if the risk for surgical repair is felt to be too high and the aneurysm has a favorable location and shape for an endovascular graft.
Very rarely, some patients with popliteal or femoral aneurysms may initially have a limb that is beyond saving because of extensive gangrene or infection or they may be too sick to undergo bypass surgery. In these cases, the vascular surgeon may need to perform an amputation as a last resort.