Aortic Aneurysm is a medical condition in which the Aorta (the major blood vessel which starts from the heart and ends up supplying blood to various parts of the body) enlarges in size and becomes about 1.5 times more than the normal. The aorta has a thickness of a garden hosepipe, and its runs from the heart passing the center of your chest and abdomen. Therefore this abnormality mainly occurs at the abdominal aorta and also sometimes be seen at the thoracic aorta too. When this condition occurs at the abdominal part (which is more common) the condition is known as Abdominal Aortic Aneurysm (AAA). AAA involves the enlargement of the lower part of the aorta. When this aortic Aneurysm occurs at the thoracic portion of the aorta it is known as the Thoracic Aortic Aneurysm (TAA) or Thoracic Aortic dissection.
Signs and Symptoms
The thoracic aortic aneurysm involves the enlargement and weakening of the upper part of the aorta. The term aneurysm is generally used when the axial diameter of the thoracic aorta becomes greater than 5 cm but when it measures about 4-5 cm the name ‘dilatation’ is used. The portion of the aorta becomes so weak that it can burst. The bursting may occur in rare cases and until it occurs the body does not shows any symptom or signs of the abnormality. If an aneurysm bursts, one or more layers of the walls of the aorta splits which causes a sudden and sharp pain at the upper portion of the back. This pain quickly radiates downwards and causes discomfort in the arms, chest, neck and jaw. There is difficulty in breathing also. This thoracic aortic aneurysm condition is mainly seen in the males of the age group between 50-60 years but is a very condition which occurs in about 6-7 persons out of 100,000.
How is a Thoracic Aortic Aneurysm Diagnosed?
Pathologically the aneurysm can be divided into mainly two types depending on their relationship with the aortic wall: True Aneurysm and Pseudo Aneurysms.
True Aneurysm is characterized by the involvement of all the three layers of Aorta i.e. Tunica Adventitia, T. Media and T. Intima. The danger of rupture is directly proportional to the extent of the aneurysm. The walls might be attenuated. The risk involved is comparatively less.
Pseudo Aneurysms carries a higher risk and high mortality rate of about 80-90%. They occur as a result of major thoracic trauma, both blunt and penetrating. The patient is unable to survive and dies even before reaching the hospital.
CTA scan and MRA scan are also common choices to diagnose and locate the condition of thoracic aortic aneurysm. When the imaging of the chest is done it may be identified when a mass effect on the airway tube or esophagus is seen. It will also be visible when there is a complication, rupture, aorto-bronchial fistula etc. Ultrasound is not of much use in the diagnosis of TAA or thoracic aortic aneurysm however the descending aorta can be visualize upto large extent with the help of Transoesophageal echocardiography but because it involves invasion it is not much used.
Treatment and Prognosis for Thoracic Aortic Aneurysm
If there is not any early diagnosis of thoracic aortic aneurysm it proves to be fatal in maximum number of individuals. The reason for death of the patient is either due to direct complication of the aneurysm or due complications of heart. The rupture depends on the size and speed of the growth. The only treatment for it is surgery. Sometimes endovascular repair is done as a treatment of choice for thoracic aortic aneurysm to reduce mortality.