An aneurysm is an abnormal dilation of the wall of an artery that leads to weakening of the artery. As a result, the artery may rupture and cause serious internal bleeding and, possibly, death.
Aneurysms occur most often in the body's largest artery, the aorta, but can occur in smaller arteries such as the cerebral (brain), renal (kidney) and carotid (neck) arteries. Ruptures in the arteries of the brain cause brain hemorrhages, which will lead to stroke like symptoms. Aneurysms can occur in the arteries of the legs, but these arteries are less likely to cause serious problems.
Aortic aneurysms usually develop at a region on the artery weakened by atherosclerosis and long-standing high blood pressure. Blood vessel walls are comprised of multiple layers of muscle and connective tissue. When plaque deposits form on the inside of the artery, oxygen and other nutrients cannot penetrate to get to the middle layer of tissue. The lack of nourishment weakens this tissue. Eventually, the force of the pounding blood vessels stretches the damaged vessel wall. In addition to atherosclerosis, recent studies have indicated that there may be other factors causing aneurysm formation; these include hereditary factors, abnormalities in the blood vessel wall matrix, and other hemodynamic factors related to poor blood pressure control. Bacterial infection may also be a source of arterial wall compromise. In this case, the most common organism found is Salmonella. This type of aneurysm is usually found in the abdominal aorta and is also known as a Mycotic abdominal aortic aneurysm.
In most cases, aortic aneurysms do not cause any symptoms unless they rupture. They can form in the thoracic area (chest) or the abdominal area. Abdominal aortic aneurysms are frequently asymptomatic. They are often discovered when the doctor examines your abdomen or during imaging procedure - such as an ultrasound, computed tomography, magnetic resonance imaging, or X-ray — usually for an unrelated problem.Thoracic aortic aneurysms are also usually asymptomatic and found during an imaging procedure, but when large, may cause symptoms that include:
- Chest pain
- Back pain
- Shortness of breath
- Coughing
- Feeling full after only eating little
Large aortic aneurysms can rupture, causing sudden, severe stabbing pain (most often back pain), often followed by loss of consciousness. The loss of blood into the chest or abdomen results in shock. About 80% of those who have ruptured aneurysms die, half of them before reaching the hospital.
Treatment for aortic aneurysms that are small (usually less than 4.5 cm in diameter) consists of controlling associated risk factors (elevated cholesterol, smoking and high blood pressure). These small aneurysms should be monitored frequently to note any changes in size. The treatment for aortic aneurysms that reach a certain size (usually > 5 cm) or are enlarging over time is surgical repair. The surgeon replaces the damaged part of the aorta with a tube of synthetic material. Most candidates for aneurysm surgery have extensive cardiovascular disease, therefore there is about a 4% risk of heart complications, double the risk for most other kinds of surgery. For this reason, doctors usually wait until the aneurysm is 4.5 cm in diameter before operating, or if there is evidence of expansion or symptoms.A new treatment involves inserting a synthetic tube, called a stent, inside the aorta, at the point of disease. This procedure repairs aortic aneurysms without the trauma of surgery. All of the pressure in the blood pushes against the walls of the tube, and not against the weakened natural walls of the aorta, reducing the chance of rupture.
