What is An Aortic Aneurysm?
The aorta is the major blood vessel of the body carrying blood from the heart through the chest and abdomen giving off branches to all organs. An aneurysm can occur in any blood vessel and is defined as an enlarged in the diameter of the artery twice its normal size. The normal diameter of the aorta can vary depending on its anatomical location in the body, gender, and age of the patient. In general, the diameter of the aorta is between 1.5 and 2.5 centimeters. An aortic aneurysm occurs when there is a weakening in the wall of the aorta. The various reasons for weakening of the aortic wall are infection, atherosclerosis, trauma, high blood pressure and inheritable diseases. The cause of an aortic aneurysm may give insight of the natural history of the aneurysm, likelihood of rupture and timing of treatment.
Aortic aneurysms are named according to the segment of the aorta, which is enlarged. In addition, various classifications of aorta aneurysms indicate the extent of the aneurysm as well as the segment involved. A true aneurysm is when all the layers of the aortic wall are weakened as opposed to a false or pseudoaneurysm when only the outer layer is weakened.
Aneurysms can expand over time however, prediction of when and in whom is difficult. The size, location and the patient’s other medical problems, smoking habits may influence the growth rate of aortic aneurysms. Aortic aneurysms related to an aortic dissection can expand more rapidly and develop complications. Patients with underlying genetic connective disorder, such as Marfan and Elher-Danlos Syndrome are more likely to develop aneurysms and expand quickly.
Most aortic aneurysms do not cause symptoms until they are very large or develop a complication. As aneurysms enlarge they sometimes cause symptoms such as pressure on adjacent structures, for example, hoarseness by pulling on the nerve to the larynx or difficulty swallowing by compressing the esophagus. Asymptomatic aortic aneurysms are usually discovered by a non-specific imaging study performed for another medical condition. However, most common symptoms of aortic aneurysms are vague chest pain, sharp back pain and abdominal pulsation.
Most large aortic aneurysms are concerning due to the possibility of rupture or development of dissection (a partial tearing of the blood vessel wall). If an aneurysm tears or leaks, the patient usually experiences severe pain. This symptom may be present when an aneurysm expands rapidly. If a patient carries a diagnosis of an aortic aneurysm these symptoms should prompt immediate medical attention preferably in an emergency room.
In an individual with an aortic aneurysm that is not causing symptoms the decision to recommend elective surgery is based on the opinion that the risk of rupture is significantly greater than the risk of elective surgery. Factors such as age, the presence of heart, lung, and kidney disease impact not only on surgical risk but also the risk of rupture. Reliance on a single factor such as maximum aortic diameter to indicate the necessity for surgery is no longer sufficient. Careful analysis of institutional operative outcomes and the natural course of untreated aneurysms allow more accurate and individualized treatment.