The aorta is the largest blood vessel in the body. It is the conduit for blood from the heart to other organs. It traverses the majority of the thorax and enters the abdomen before dividing into its terminal branches, which supply the lower limbs with blood. An aneurysm is an abnormal enlargement of any segment of an artery. That is, the diameter of that segment of the artery is 1.5 times or more greater than the norm.
Risk Factors
Abdominal aortic aneurysms are associated with several diseases and lifestyle choices including hypertension, diabetes, obesity, high cholesterol, increasing age and smoking, according to the "Sabiston Textbook of Surgery." These risk factors adversely affect the walls of blood vessels making them less elastic and therefore less able to withstand the fluctuations in blood pressure. The effects on the artery are not uniform and thus different segments enlarge to form aneurysms.
Symptoms
According to the medical textbook "Masters of Surgery 3rd Edition," 70 to 75 percent of abdominal aortic aneurysms do not cause any symptoms and are discovered when persons present to their doctors for other reasons. When the symptoms do occur, the most common is abdominal or back pain. Occasionally, a pulsating mass in the abdomen is noted. When an aneurysm ruptures, persons usually experience a sharp severe pain in the back or abdomen that may be associated with fainting and weakness from massive blood loss
Tests
"Sabiston Textbook of Surgery" states that, for suspected aneurysm, an abdominal CT scan is the most precise test, although the aneurysm may be visualized with an abdominal ultrasound or MRI. The scan can demonstrate the size and extent of the aneurysm which are important determinants of the need for treatment.
Treatment
The only definitive treatment for aneurysms is surgery. Not all aneurysms require surgery, however. "Masters of Surgery, 3rd Edition" notes that aneurysms that are less than 5 cm in diameter do not require surgery unless they rupture. These aneurysms are usually observed closely by serial CT scans. Any underlying conditions, such as hypertension, that increase the likelihood of rupture are stringently controlled.
Aneurysms greater than 5 cm or those which are severely symptomatic are surgically repaired as the risk of rupture outweighs the risks involved with surgery. Surgical repair involves removal of the enlarged segment and replacement with a synthetic graft.
Prognosis
The outcome after surgical treatment of abdominal aortic aneurysms is quite good, with the risk of fatality being approximately 5 percent, as cited in "Masters of Surgery 3rd edition."
References
- "Masters of Surgery, 3rd Edition"; L. Nyhus et al.; 1995
- "Sabiston Textbook of Surgery"; C. Townsend et al.; 2008
