Thoracoabdominal Aortic Aneurysm

Thoracoabdominal Aortic Aneurysm (also called TAAA or T triple A)

What is it?

Thoracoabdominal Aortic Aneurysm

A thoracoabdominal aortic aneurysm is a bulging in the aorta that extends from the chest to the abdomen. Thoracoabdominal aneurysms are often one of the most complex aortic aneurysms to treat due to the complexity of their location.

Thoracoabdominal aneurysms are classified according to the Crawford Classification:

  • Extent I: involves the majority of the descending thoracic aorta as well as the upper abdominal aorta.
  • Extent II: involves the majority of the descending thoracic aorta and the majority of the abdominal aorta
  • Extent III: involves the lower descending thoracic aorta and the majority of the abdominal aorta.
  • Extent IV: involves most or all of the abdominal aorta
  • Extent V: involves the lower descending thoracic aorta and the upper abdominal aorta.

The decision to treat TAAAs is based on several factors, the most important of which is size. The general recommendation is to repair TAAAs when they reach 5.5 cm – 6.0 cm in diameter as the risk of rupture becomes significant.

Examples of Type 1-4 Aneurysms

Causes & Risk Factors

The most common cause of thoracoabdominal aortic aneurysms is atherosclerosis which is a hardening of the arteries caused by plaque buildup. Over time, this plaque can cause the walls of the aorta to become stiff and weak, creating the potential for an aneurysm to form.

Some factors that increase your risk for atherosclerosis, (and increase your risk for developing a thoracoabdominal aortic aneurysm) are:

  • Smoking
  • High blood pressure
  • High cholesterol
  • Being overweight
  • A family history of cardiovascular disease

Other factors that increase your risk for developing a thoracoabdominal aortic aneurysm are:

  • Older age
  • Gender (occurrence in males is more prevalent than females)
  • Family history of aneurysms
  • Diabetes
  • Genetic disorders that effect connective tissue such as Marfan Syndrome, Ehlers-Danlos syndrome, Loeys-Dietz syndrome.
  • Infection or injury to the aorta

Symptoms

It is common for thoracoabdominal aortic aneurysms to form without symptoms but some can include:

  • A pulsating mass in the abdomen
  • Sudden onset of intense pain in the abdomen, chest or lower back

Symptoms of a ruptured thoracoabdominal aortic aneurysm include:

  • A drop in blood pressure
  • An increased heart rate
  • Dizziness or lightheadedness
  • Severe pain

Diagnosis

In addition to your physician getting your complete medical history and doing a physical exam, they may order any of the following tests:

  • Computed tomography (CT) scan
  • Magnetic resonance imaging (MRI)

Treatment

After taking into consideration the size and Crawford Classification of your aneurysm along with your medical history, risk factors, and overall health status, your doctor will explain and recommend the most suitable treatment. Treatment options include:

  • Medical management (blood pressure control, smoking cessation, etc.)
  • Open Repair

Open repair of a TAAA is a highly complex procedure that has been performed for many years. It involves making an incision along the side of the chest and abdomen in order to visualize and replace the diseased segment of aorta with a new tube (e.g., a synthetic graft).

Because of the complex location of these aneurysms and their involvement of important branches off the aorta, there are no straight forward endovascular (minimally invasive) repair options for TAAAs. A Hybrid Repair combines an endovascular repair (TEVAR) for the thoracic (chest) component with an open repair for the abdominal segment. During the TEVAR, a stent-graft is deployed within the diseased segment of aorta using wire and catheters that are passed through small groin incisions. This hybrid approach may lessen the morbidity of an entirely open repair.

Total endovascular treatment options for TAAAs require stent-grafts to have multiple holes (fenestrations) or branches in order to permit blood flow to important branches off the aorta. These devices are currently experimental and thus limited to device trials and/or off-FDA label use of currently available stent-grafts. Your surgeon can speak to you about your candidacy for such a device.

  • Fenestrated Endovascular Aortic Repair (FEVAR