What is Thoracic Aortic Aneurysm (TAA)?
Disease of the aorta is the 12th leading cause of death in the United States. Aneurysms of the aorta can occur in the chest or abdomen, or both at the same time. The aorta is the main blood vessel carrying arterial blood from the heart to the rest of the body. It begins in the chest and ends in the abdomen, and along its course, it branches off to the head and neck, arms, chest, abdomen (including the kidneys, liver and intestines) and finally the legs.
An aneurysm is defined as an enlargement of the arterial wall of more than 150% of the diameter of the normal artery. The artery wall is made out of special elastic proteins that can withstand the blood’s pressure and be pliable at the same time. The normal consistency of the artery is like a cooked noodle, but when it degenerates and hardens, it becomes stiff and brittle, like an uncooked noodle. This process occurs because of arteriosclerosis, or hardening and degeneration of arteries. The term arteriosclerosis (comes from the Greek words for blood vessel and hardening. Another term used is atherosclerosis: Athero means gruel and sclerosis means hard). This can lead to enlargement of the artery because of the breakdown in its structure. In turn, this breakdown leads to weakness in the wall, thus leading to further enlargement. In some cases of aortic aneurysm, there is no atherosclerosis, but instead there is an inherited abnormality of the blood vessel wall that causes aneurysms to form, such as a condition known as Marfan syndrome.
When the artery is enlarged, it is like a balloon; the larger it gets, the weaker it is and the higher the chance of its rupturing. Ruptured aneurysms can kill suddenly. Some people are fortunate enough to survive the first rupture or leak. This is like a punctured tire, which may leak slowly, often allowing you to repair it and fill it before it goes flat, but if the hole is large enough, the tire will go flat immediately. There are other diseases that can occur in the aorta, such a tear from blunt trauma (most commonly high-speed car accidents), dissection, inflammation (Takayasu’s arteritis) or infection.