Types of Aneurysms

An aneurysm is a ballooning of the wall of an artery or vein because of weakness caused by trauma, disease, genetics or atherosclerosis. The most common sites are the cerebral arteries of the brain or the aorta, which takes blood from the heart to the rest of the body. An aneurysm may cause pressure or rupture with hemorrhage.

Structures

• Berry saccular aneurysms have a stem with a ballooning at the end while fusiform aneurysms are large (over one inch) and irregular in shape, causing pressure but rarely rupturing. Dissecting aneurysms tear apart the lining of the vessel walls, allowing blood to enter the different layers, eventually rupturing.

Cerebral aneurysm

• These are usually small (2 to 7 mm) and congenital and develop in the Circle of Willis at the base of the brain, with rupture causing stroke or death.

Aortic Aneurysm, Thoracic

• These are in the chest, near the heart, and pose a great risk if they rupture, so they are usually repaired when diagnosed, but surgery carries significant risk.

Aortic Aneurysm, Abdominal

• These are less dangerous and are usually monitored--with surgery delayed--until they increase to more than 2 inches in diameter, increasing risk for rupture.

Considerations

• A ruptured aneurysm carries a 90 percent death rate. Aneurysms can be repaired by placing stents (tubes) in the vessels, surgically removing the damaged area or (in the brain) placing clips on the vessels.