The aorta is the largest artery in your body. It carries all the blood that is pumped out of your heart and distributes it, via its many branches, to all the organs of your body. The aorta passes upwards from your heart before curving backwards and downwards and travelling through your chest (the thoracic aorta) and into your abdomen (the abdominal aorta).
The aorta is usually 2 to 3cm (about one inch) in diameter. A weak spot in the aorta can cause it to bulge outwards (called an aneurysm). If the bulge occurs in the aorta as it goes through your chest, it's called a thoracic aortic aneurysm. If it occurs in the aorta as it goes through your abdomen, it's called an abdominal aortic aneurysm (AAA). AAAs are more common than thoracic aneurysms.
The chance of an aneurysm rupturing depends on its size. If your aneurysm is greater than 5.5cm wide the chances of rupture are high and the risk increases with increasing size.
Symptoms of thoracic aortic aneurysm
A thoracic aortic aneurysm often causes no symptoms. However, if it starts to expand and push on surrounding tissue or nerves in your chest, it can cause:
- chest pain (as the aneurysm widens the pain will spread into your upper back)
- back pain
- difficulty breathing
- difficulty swallowing
These symptoms aren't always caused by thoracic aortic aneurysms but if you have them, you should see a doctor.
Complications of thoracic aortic aneurysm can include the following.
If the aneurysm occurs near your heart it may cause the aortic valve to leak. This can cause blood to flow back into your heart (called aortic regurgitation) and stop your heart pumping effectively and cause heart failure.
Very rarely, the inner lining of the aorta tears and blood enters the wall of the aorta separating the layers that make up the aortic wall. If this happens, you may feel sudden and excruciating chest and back pain.
If the aneurysm ruptures it causes severe internal bleeding and can be fatal without emergency surgery to repair it. The risk of an aneurysm rupturing increases as it gets wider.