Thoracic Aortic Aneurysm (Stretched Aorta in the Chest)
The thoracic aorta is found in the chest (in between the neck and the diaphragm).
It is connected to the outlet of the left ventricle (left chamber of the heart), it arches over the left side of the airway and descends along the spine in the left chest to enter the abdomen through the diaphragm to become the abdominal aorta. Its primary function is to carry red, oxygenated blood away from the heart and distribute it throughout the body.
The wall of the aorta is made up of three layers. First, is the inner layer which is called intima, the middle layer also known as media and the outer layer is the adventitia.
Overtime degenerative diseases such as hypertension, connective tissue diseases (Marfan’s Syndrome, Loeys Dietz syndrome, etc.), high cholesterol levels, and ageing may cause the middle layer of the aorta to thin out thereby weakening the wall of the aorta. The affected walls may bulge or stretch resulting in enlargement of the aorta known as aneurysm formation.
Most of the time, a thoracic aortic aneurysm does not cause any signs or symptoms and but is life threatening once it reaches a certain size as it may rupture. Just as the wall of a balloon thins and then ruptures as it expands, the stress on the wall of the aorta as it expands causes it to progressively thin and then suddenly rupture. This is rare until the aorta reaches a diameter of 5 cm. As the bulge or the swelling grows it can also cause problems by compressing nearby structures in the chest.
Most commonly the presence of an aneurysm is a risk for rupture. The larger the swelling the more likely it is to bleed. Aneurysms over 6 cm have a 30% annual risk of rupture which can result in death. However, early detection and screening may avoid such complications. An open chest surgery may take place to repair or replace the damaged aorta.
Causes of Thoracic Aortic Aneurysm
- Atherosclerosis - is a condition where in there is an abnormal hardening of some parts of the arteries that is caused of a build-up of fatty substances and other body-attacking elements. As the other areas harden the other areas are left weak therefore, the strength of your arterial walls is unlevelled. The weaken area will not be able support the normal blood flow so it develops the stretching affect which causes swelling (aneurysm).
- Ageing - as the person's age increases the normal structure or condition of the aorta will occur and it becomes less elastic and stiffer with age.
- Genetics – is also one of the primary factors of thoraco-abdominal aortic aneurysm. Some people are born with a weak aorta (blood vessel) because it is inherited in their family’s genes. Therefore, they will be more prone to developing enlargement of blood vessels, especially the aorta.
- High cholesterol, High blood pressure, smoking and Diabetes are just some of the many factors that would place a person at increased risk of developing thoracic aortic aneurysms.