An aneurysm is a dilation of an artery
The aorta is a blood vessel about the diameter of a garden hose. It carries oxygen-rich blood from the heart down through the chest to the abdomen, where it branches into a blood vessel serving each leg. Aneurysms can occur anywhere along the aorta, but they are most common in the section of the aorta that runs through the abdomen.
An aortic aneurysm can rupture. If the bulge in the aorta is large enough, there can be severe internal bleeding. Every year, about 17,000 people in North America die of ruptured aortic aneurysms, although many aortic aneurysms can be surgically repaired if they are caught in time.
Two Types of Aortic Aneurysms
There are two types of aortic aneurysms, degenerative aneurysms and dissecting aneurysms.
Degenerative aneurysms are more common. These are breakdowns in the connective tissue that holds the aorta in place within the muscles of the chest and abdomen. More common in smokers, they can be caused by high blood pressure or genetic conditions.
Dissecting aneurysms are due to a tear in the wall of the artery itself. Every artery is surrounded by a wall made of three layers. When these layers begin to separate, a little like plywood left out in the rain, the wall of the aorta weakens, and the artery enlarges. Dissections can occur anywhere along the aorta, but they are more common in the abdomen. A dissecting aneurysm along the ascending aorta (providing blood to the brain) is usually treated with surgery, while a dissecting aneurysm along the descending aorta (providing blood to the lower parts of the body) is usually treated with medication to control blood pressure. Dissecting aneurysms are almost always fatal if they are not treated.
Aneurysms in the Aortic Arch
The way the aorta fits into the body is that it first ascends, then bends, and then descends. The bend in the aorta is also known as the aortic arch. The aortic arch is neither ascending nor descending. Aneurysms in the aortic arch may or may not be treated with surgery.
Unlike aneurysms at other points along the aorta, aneurysms along the aortic arch often present symptoms. There may be a mild fever, fatigue, loss of appetite and loss of weight, joint pain, chest pain, achy muscles, and swollen glands, much like a case of the flu. After a few days or weeks, inflammation of the aortic arch sets in. There may be cramping, constipation, heartburn, or nausea, due to poor circulation to the abdomen, cold or pale hands and feet, high blood pressure, weak pulse, and vision problems. There will also usually be a difference in blood pressure measured in the arms and in the legs. People with aneurysms in the aortic arch are usually very aware that they are sick.
Drugs or Surgery for Aortic Arch Aneurysms?
Anyone who is diagnosed with an aneurysm in the aortic arch will be given medications to control high blood pressure. Almost every patient will be advised to lose weight, and almost every patient will be given a statin drug not just to lower cholesterol numbers but also to control the inflammation that cause plaques to burst in the lining of the aorta—a potentially deadly event for people who have aortic arch aneurysms. In younger patients, some as young as 10 to 30 years old, who have a form of autoimmune disease known as Takayasu's arteritis, the doctor may also prescribe steroid drugs (which make weight loss quite difficult but which may be necessary for stabilizing the artery).
Doctors can tell how active the underlying disease is with a blood test called the erythrocyte sedimentation or "sed" rate. If the underlying inflammatory processes are in full swing, it may not be wise to operate to repair an aneurysm. These patients are treated with "watchful waiting," although it is usually necessary to give larger and larger doses of steroid drugs (or steroid-sparing drugs, such as methotrexate or cyclophosphamide, more commonly used in cancer treatment).
Eventually, however, surgery may be essential. The need for surgery is indicated by:
- Kidney failure,
- Severe lack of blood flow to the legs or
- Decreased blood flow to the brain.
In these situations, surgery may be essential, but it may not be necessary to operate on the aneurysm itself.
Surgical Options for the Aortic Arch
When aortic arch disease causes kidney failure or severe problems with walking, the surgeon may opt to do angioplasty (expanding the aorta with a balloon) or to insert a stent to keep the aorta open. Usually these procedures make a major difference in the patient's quality of life for 1 to 2 years, but symptoms eventually return. Longer-term well being may require surgery on the aortic arch itself.
Usually the aneurysm is repaired with a bypass. The surgeon strips a vein from patient's leg and uses it to route blood around the aneurysm in the aorta. Bypass surgery gives longer-term relief than other kinds of surgeries, but there is significant risk with the procedure. Only a skilled surgeon who performs this surgery on a regular basis (a surgeon who does the procedure several times a week) should be used to do the operation. Your surgeon will be able to give you an assessment of the risk of death or brain injury, if any, during the procedure.
What If I Choose Not to Have Surgery?
About one in five people with aortic arch aneurysms will get well without treatment. Women who get pregnant, however, put severe strain on the aortic arch, and anyone who is unable to stick to a low-calorie, cholesterol-control diet and lose weight is also likely to have continuing problems with the disease.
Sometimes symptoms get better and worse irrespective of medical treatment. The course of aortic arch disease is not totally predictable. If you have this unfortunately condition, however, you absolutely must keep your blood pressure under control and take all medications on a consistent, regular basis.