Aortic Aneurysm

Treatment Considerations related to Thoracic Aortic Aneurysm

Normal Aorta

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Thoracic aortic aneurysm repair depends on its location. In the ascending aorta (in the front, near the heart) surgery is often indicated if the aorta reaches 5 or 5.5 centimeters (cm) in diameter. If the aneurysm is in the descending thoracic aorta, surgery is generally delayed until it is about 6 cm in diameter. These are general guidelines, however, and if circumstances such as Marfan Syndrome or aneurysm growth are present, surgery may be recommended sooner.

Aneurysms involving the ascending aorta are repaired by cardiac surgeons. Repair may require replacement only of the ascending aorta or, if the aortic valve is damaged, it may require aortic root replacement. Techniques for aortic root replacement or repair include valve-sparing techniques, reconstruction with biological valves such as stentless xenografts and composite root replacement with a mechanical-valved conduit. Surgeons at Mayo Clinic in Rochester are expert in all these procedures.

Depending on how far the aneurysm extends, the repair may require profound hypothermia and circulatory arrest. The patient is placed on cardiopulmonary bypass and the body temperature cooled so that blood flow can be stopped for a few minutes while the repair is carried out. After the repair, blood flow is restored and the patient is rewarmed. The risk of complications during this kind of repair is low in experienced hands, but depends on the patient's condition.

If the aneurysm involves the aortic arch, cardiac surgeons typically perform the repair. When the aortic arch is involved, stopping blood flow is required in almost all cases. The arch can be reconstructed in various ways, including branched grafts which provide separate connections to the vessels that lead to the head and arms.

Aneurysms that involve the chest above the diaphragm may be repaired by cardiac surgeons or vascular surgeons. Depending on the location of this aneurysm, circulatory arrest or partial bypass (left heart bypass) may be required. These techniques are used to minimize the risk of complications related to interrupting the blood flow while the repair is being done.

Abdominal aortic aneurysms are typically repaired by vascular surgeons. The most advances have been made with endovascular stent grafts. When an aneurysm involves both the chest and abdomen, it is called a thoracoabdominal aneurysm. Such aneurysms are typically repaired by a team of vascular and cardiac surgeons. Thoracoabdominal aneurysms carry the highest risk and, therefore, surgical repair is typically done only in high-volume medical centers such as Mayo Clinic.