The aorta is a major blood vessel that stems from the heart and extends through the diaphragm and down to the abdomen. The abdominal aorta is the section of the aorta that extends to the abdomen. It supplies blood and oxygen mainly to the organs in the abdomen and pelvis and to the legs. The walls of the abdominal aorta may weaken due to various factors. When this happens, the pressure exerted by blood flowing through the aorta may cause the weakened area of the vessel to enlarge or expand. The Society of Thoracic Surgeons states that when a section of the aorta exceeds 1.5 times its normal diameter, this is known as an aortic aneurysm. According to the Mayo Clinic, 75 percent of aortic aneurysms occur in the abdominal aorta.
Atherosclerosis
According to the Milton S. Hershey Medical Center, atherosclerosis may lead to an enlarged abdominal aorta. Atherosclerosis is the thickening or hardening of the linings of the arteries. When this condition affects the abdominal aorta, it can weaken the vessel. The pressure from blood passing through the abdominal aorta can push the weakened spot outwards, forming an aneurysm. In time, if left untreated or if not detected earlier, the aneurysm may eventually rupture.
High Blood Pressure
MayoClinic.com states that high blood pressure can result in an enlarged abdominal aorta. In high blood pressure, the heart works harder to pump blood through the aorta to the different parts of the body. The hard pumping of the blood through the aorta may weaken the walls of the abdominal aorta over time. This weakening can cause the formation of an aneurysm. Depending on its size, an abdominal aortic aneurysm can be life threatening as it may rupture and result in internal bleeding and death.
Injury
The Society of Thoracic Surgeons reports that an injury can cause swelling of the abdominal aorta. For example, the force generated by a sudden stop from motion, such as occurs in a car accident, may create a tear in the wall of the abdominal aorta. Over time, the walls of the abdominal aorta around the tear can weaken further due to pressure from blood flow, causing enlargement and the formation of an aneurysm.
