A thoracic aneurysm is an abnormal bulging of the aorta in the chest. The aorta is the main blood vessel carrying blood out of the heart, sending branches to head and neck and arms before arching over and down the body to supply the internal organs and lower limbs. Thoracic aneurysms are not as common as aneurysms of the lower aorta, but they tend to be more complicated to treat.
Thoracic aneurysms are classified depending on whether they arise in the ascending or descending thoracic aorta, and on which aortic branches are involved. Aneurysms affecting the ascending aorta may also involve the aortic valve which controls the flow of blood leaving the heart. Generally speaking, the more branches that are involved, and the closer to the aortic valve the aneurysm extends, the more complicated it is to treat.
Treatment of thoracic aneurysms
Open surgery for thoracic aneurysms is a major undertaking and carries a high risk of complications. For this reason, many conventional open operations have been replaced by endovascular (key-hole)
procedures where the diseased segment of aorta is repaired by placing a new lining inside the artery under X-ray control. This is called stent-grafting, or thoracic endografting.
Thoracic aneurysms that involve a segment of aorta away from major branches are relatively straightforward to treat with a stent-graft. This can be done via a small groin incision and the graft deployed via the femoral artery. This can be done under general, epidural or local anaesthetic.
More extensive aneurysms may require more complex procedures. These may be staged over more than one operation. Typically, a bypass is performed from one artery to another in preparation for the deployment of a longer stent-graft which deliberately blocks off the diseased blood vessels that have been affected by the aneurysm. Such hybrid operations allow complex thoracic aneurysms to be treated without requiring open chest surgery with its attendant risks.