An abdominal aortic aneurysm occurs when there is focal dilation of the abdominal aorta caused by weakening in the aortic wall. This results in an increased diameter of the aorta over time.
Tobacco use is the leading risk factor for abdominal aortic aneurysm (AAA) development. The most serious complication is rupture, which is usually fatal. Repair is recommended if the AAA grows more than 1 cm per year or if greater than 5.5 cm in diameter. Left untreated, the annual rate of AAA rupture is 9.4% for aneurysms between 5.5 cm and 5.9 cm, 10.2% for aneurysms between 6.0 cm and 6.9 cm (actually, 19.1% for the subgroup between 6.5 cm and 6.9 cm), and 32.5% annual rupture rate if the AAA is greater than or equal to 7.0 cm.
Repair can be done surgically (open) or via endovascular repair (via femoral approach). These approaches have similar long-term mortality; however, endovascular repair requires shorter hospitalization and quicker return to normal activities, but a larger number of repeat procedures and not all patients are candidates for this depending on the morphology of their aneurysm. Short-term mortality is higher with surgical repair, although it equalizes long-term compared with endovascular repair. Note that aortic aneurysms can also occur in the descending thoracic aorta or the ascending aorta, and management for these aneurysms is different.