by Maria Adams, MS, MPH, RD
Anatomy and Physiology
Your heart pumps blood that is carried by arteries to organs and tissues throughout your body. Your veins return the blood back to the heart. With few exceptions, arterial blood is oxygen-rich, while venous blood is oxygen-depleted.
The largest artery in the body is the aorta, which is attached to the heart and receives blood directly from the left ventricle, or main pumping chamber. The aorta is divided into four parts: Ascending aorta, aortic arch, thoracic aorta, and abdominal aorta.
The abdominal aorta is the last and largest section of the aorta. It supplies blood to the lower regions of your body, including the organs in the abdomen and pelvis. The abdominal aorta ends around navel level, where it splits into the two iliac arteries that carry blood to the legs.
Reasons for Procedure
The thick walls of the aorta are designed to handle the high blood pressures inside. Over time, the walls may weaken in certain parts of the aorta, causing it to expand or bulge like a balloon. This condition most commonly occurs in the abdominal aorta and is referred to as an abdominal aortic aneurysm.
Atherosclerosis, which is a buildup of fat, cholesterol, and calcium inside the arteries, is the most common cause of abdominal aortic aneurysms. This gradual build up of plaque can weaken and damage the aortic wall, making it more susceptible to an aneurysm. Other risk factors for developing an abdominal aortic aneurysm include: Age over 55 among men and 65 among women, high blood pressure, smoking, a history of other forms of cardiovascular disease, like heart attack or stroke, and a family history of aneurysms. Often, a person with an abdominal aortic aneurysm will have no symptoms. In fact, most aortic aneurysms are diagnosed during an unrelated medical visit. Some people, however, may experience: a pulsating sensation in the abdomen, sudden pain in the abdomen or lower back, which generally indicates the aneurysm is about to burst or has already ruptured. To diagnose your abdominal aneurysm and determine its size and location, your doctor will most likely perform one or more of the following tests to produce images of your abdominal aorta and surrounding structures: computed tomography, or CT scan, which uses x-rays and a computer to generate an image; abdominal ultrasound, which uses high-frequency sound waves; magnetic resonance imaging, or MRI, which uses a powerful magnet, radio waves, and a computer. An abdominal aortic aneurysm repair can be performed either to prevent an aneurysm from rupturing, or to treat one that has already ruptured. The chance of surviving a ruptured aneurysm is less than 50%. It is, therefore, important to repair an aneurysm while it is still intact.
A normal aorta is about one inch in diameter. The larger an aneurysm becomes, the more likely it is to rupture. Doctors generally recommend repairing abdominal aortic aneurysms once they become larger than two inches, or five centimeters, in diameter, or if they are causing symptoms.
If your aortic aneurysm is less than two inches and you have no symptoms, your doctor may recommend closely monitoring and reassessing your condition every six months. This is known as watchful waiting.
There are two different methods used to repair an abdominal aortic aneurysm. The most common and traditional repair is to surgically replace the weakened area of the aortic wall with an artificial tube, or graft.
A newer, less invasive technique is known as an endovascular stent graft. In this procedure, a surgeon inserts a catheter in an artery downstream and threads it up to the aneurysm. Once there, the surgeon places a stent graft made of metal and fabric inside the aorta to strengthen it and prevent it from bursting. While endovascular stenting is being used more and more, not all patients are candidates for this procedure.
In the days leading up to a scheduled abdominal aortic aneurysm repair: 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 to swallow medications you may be told to take. You may be given antibiotics to take before the procedure to help prevent an 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. An IV line will be started prior to your procedure in order to provide you with fluids, antibiotics, and anesthesia. You may also have a special line started in your wrist artery to monitor your blood pressure on a continuing basis. A catheter will be inserted into your bladder after you are asleep to drain your urine and monitor your kidney function.
A traditional open surgical repair is performed under general anesthesia, which means you will be asleep for the duration of the procedure. A breathing tube will be inserted through your mouth and into your windpipe to help you breathe during the operation.
Your surgeon will begin by making an incision from the breastbone to below the navel. He or she will then locate the aneurysm and clamp the aorta just above and below it.
Next, your surgeon will remove any blood clots inside the aneurysm and repair any openings in the aneurysm wall. Your surgeon will then open the aneurysm and sew an artificial graft, the same size and shape as a healthy aorta, into place. The graft will reinforce the walls of the aorta.
Finally, your surgeon will stitch the wall of the aneurysm closed over the newly placed graft, and close the abdominal incision with stitches. The total length of this procedure is usually 4 to 6 hours.
Risks and Benefits
Possible complications of a traditional open abdominal aortic aneurysm repair include: excessive bleeding, injury to the ureters, which connect the kidneys to the bladder, injury to the part of the bowel supplied by branches from the abdominal aorta, post-operative ileus and bowel obstruction, kidney failure, graft or wound infection, decreased blood supply to the spinal cord, blood clots in vessels of the legs, adverse effects of the anesthesia, heart attack, and death. Potential benefits of this procedure include: prevention of the rupture of an aneurysm, a life-threatening complication, resolution of any symptoms associated with an aneurysm, and improvement of blood flow through the abdominal aorta to the legs.
In abdominal aortic aneurysm repair, or any procedure, you and your doctor must carefully weigh the risks and benefits to determine if it's the most appropriate treatment option for you.
After the Procedure
After your procedure, your breathing tube will be removed and you will be taken to the intensive care unit for recovery. You will receive fluids and nutrition through your IV. You may also have a tube inserted through your nose and into your stomach to remove secretions until your intestines regain normal functioning. The catheter in your bladder will remain in place for several days. The usual hospital stay is 5 to 10 days. During this time, your wound will be attended to and you will be encouraged to get up and out of bed often.
Once home, be sure to contact your doctor if you experience any of the following: signs of infection, such as fever and chills, redness, swelling, increasing pain, excessive bleeding, or discharge at the incision site, cough, shortness of breath, or chest pain, pain, burning, urgency, or frequency of urination, or blood in the urine, pain, numbess, or swelling in your legs.
After your surgery, you may gradually return to normal activities. Complete recovery may take 2 to 3 months. To reduce the chance of further problems with your arteries, you will need to manage any risk factors for atherosclerosis, such as high cholesterol and blood pressure, with medications and a healthful diet.
- Abdominal aortic aneurysm. MedlinePlus Medical Encyclopedia. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/000162.htm. Accessed September 12, 2004.
- Abdominal Aortic Aneurysm. Vascular Web. Available at: http://www.vascularweb.org/VascularWeb_Contribution_Pages/Patient_Information/NorthPoint/Abdominal_Aortic_Aneursym.html. Accessed September 12, 2004.
- Abdominal Aortic Aneurysm, Diagnosis. eMedicine. Available at: http://www.emedicine.com/radio/topic1.htm. Accessed September 12, 2004.
American Heart Association. Available at www.americanheart.org. Accessed September 29, 2004.
- Santilli JD, Santilli SM. Diagnosis and Treatment of Abdominal Aortic Aneurysms. American Family Physician. 1997; 56(4).
*Stent-Graft Repair of Abdominal Aortic Aneurysms. Society of Interventional Radiology. Available at: http://www.sirweb.org/patPub/abdominalAorticAneurysms.shtml September 12, 2004. by Maria Adams, MS, MPH, RD
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