Abdominal Aortic Aneurysm
An aneurysm is a localized, balloon-like expansion in a blood vessel, caused by weak vessel walls. The abdominal aorta refers to the part of the aorta, the artery that carries oxygen-rich blood from the heart to the legs, between the diaphragm and the legs. That is why the bulge that occurs in the abdominal aorta is called an abdominal aortic aneurysm. Most aortic aneurysms occur in the abdomen, and most abdominal aortic aneurysms occur beneath the kidneys and may continue into the iliac, or leg, arteries.
Complications of an Abdominal Aortic Aneurysm
The weakened, bulging vessel walls are susceptible to rupture, a catastrophic event which causes severe bleeding and pain and is often fatal. Half of all untreated abdominal aortic aneurysms end in rupture and death within five years, making them the 13th leading cause of death in the United States. Leakage, rather than rupture, may occur causing blood to flow through the inner lining into the vessel wall, known as aortic dissection. In addition, blood clots may form in the aneurysm and travel to other arteries, where they may block blood flow. Other complications are an infection and blockage of the aorta.
Causes and Risk Factors of Abdominal Aortic Aneurysm
Although traditionally it was thought that atherosclerosis, or plaque buildup, caused aortic aneurysms, it is now thought not to be related to atherosclerosis and is more properly termed a degenerative aneurysm. The biggest risk factors are genetic predisposition, hypertension, and smoking. If one has an aneurysm of the aorta, it is wise to have one’s first degree relatives ( brother, sister, child) screened for it also as there is a 15% likelihood of one of them having one as well.
- Vessel injury
- Inflammation due to disease
- Congenital deformity
- Advanced syphilis
- Fungal infection
Men are more likely than women to develop an abdominal aortic aneurysm. Being over the age of 60 also increases one’s chances of developing abdominal aortic aneurysm.
Symptoms of Abdominal Aortic Aneurysm
An abdominal aortic aneurysm may occur with no warning signs. Possible symptoms are as follows:
- Deep abdominal pain, especially in the lower back
- A pulsing sensation in the abdomen
Secondary symptoms of an abdominal aortic aneurysm may include:
- Rapid pulse
- Dry skin/mouth
- Excessive thirst
- Nausea and vomiting
- Light-headedness or fainting with upright posture
- Excessive sweating
- Clammy skin
- Rapid heart rate (tachycardia) when rising to standing position
- Impaired concentration
Diagnosing an Abdominal Aortic Aneurysm
Abdominal aortic aneurysms may be detected by manual examination by a physician, X-rays, ultrasound, CT scans, MR imaging and aortography.
Treatment for an Abdominal Aortic Aneurysm
Surgery is recommended for an aneurysm that is at great risk for rupture: if the aneurysm is more than 5 cm is size, and in a woman, more likely if it is more than 4.5 cm in diameter. Surgery is performed immediately on an aneurysm that threatens imminent rupture or has already ruptured, although a successful outcome is far less likely once the vessel has burst.
Traditional surgery involves making an incision to open the abdomen, removing the aneurysm and replacing the excised vessel piece with synthetic tubing. The traditional operative repair involves an abdominal incision. Most surgeons do a incision in the midline but Dr.Angle prefers to do a “retroperitoneal” incision, i.e. on the flank which results in quicker recovery for the patient. After the operation, usually the patient is in the hospital for 3-5 days and then discharged home.
A majority of aneurysms these days can be treated with an endovascular stent graft. Endovascular aortic aneurysm repair (EVAR) is done through either small incisions in the groin or through a needle puncture in the groin. The aneurysm is treated by inserting a stent graft that is covered with fabric through the arteries in the legs and deployed within the aneurysm. This leads to quick recovery and the patient can go home usually the next morning. The patient’s aorta and the configuration of the aneurysm, however, must meet certain criteria for this to be done successfully.
Risks of Surgical Repair
- Aortic rupture or dissection
- Hypovolemic shock
- Arterial embolism (blood clot)
- Insufficient circulation
- Kidney damage or failure
- Myocardial infarction