An aneurysm is a balloon-like bulge in an artery. Arteries have thick walls to withstand normal blood pressure. However, certain medical problems, genetic conditions, and trauma can damage or injure artery walls. The force of blood pushing against the weakened or injured walls can cause an aneurysm.
There are 2 types of aneurysms: saccular and fusiform. An aneurysm can grow large and rupture (burst) or dissect. A rupture causes dangerous bleeding inside the body. A dissection is a split in one or more layers of the artery wall. The split causes bleeding into and along the layers of the artery wall. Both rupture and dissection often are fatal.
Most aneurysms occur in the aorta, the main artery that carries oxygen-rich blood from the heart to the body. The aorta goes through the chest and abdomen.
An aneurysm that occurs in the chest portion of the aorta is called a thoracic aortic aneurysm. An aneurysm that occurs in the abdominal portion of the aorta is called an abdominal aortic aneurysm. Aneurysms also can occur in other arteries, but these types of aneurysm are less common.
About 13,000 Americans die each year from aortic aneurysms. Most of the deaths result from rupture or dissection.
Early diagnosis and treatment can help prevent rupture and dissection. However, aneurysms can develop and grow large before causing any symptoms. Thus, people who are at high risk for aneurysms can benefit from early, routine screening.