The aorta is the main blood vessel that carries blood from the heart to the body. The aortic root attaches the aorta to the heart and includes the aortic valve and the origins of the coronary arteries. The ascending aorta then goes up towards the neck, turns in the aortic arch then heads down the body as the descending thoracic aorta. Below the diaphragm it becomes the abdominal aorta. Aneurysms of the aorta are areas of enlargement greater than 50% larger than the normal aorta. Once enlarged, the aorta will never get smaller and typically continues to grow. Causes of aneurysms include smoking, high blood pressure, high cholesterol, family history, and some connective tissue disorders such as Marfan’s Syndrome. Once diagnosed, the entire aorta will require lifelong surveillance – even after repair of the aneurysm.
As aneurysms enlarge, there is an increased risk of the aneurysm rupturing or the inner layer of the aneurysm tearing, called aortic dissection. Both of these conditions can be fatal and will leave the aorta permanently damaged. Aneurysm repair is designed to prevent these complications. Elective aneurysm repair is typically done when the risk of surgery is lower than the risk of an aneurysm related complication. For most aneurysms, a discussion about repair should begin when the aneurysm reaches 4cm in diameter. Elective aneurysm repair is generally low risk, while the complications of rupture and dissection typically carry a high risk of death and permanent complications. The goal of aneurysm surgery is to remove the diseased aorta before complications occur. At the time of surgery, the aneurysmal aorta is completely removed and replaced with a graft made of synthetic material. After repair, the remaining aorta will require periodic follow-up with CT scans to be sure no additional aneurysms develop.
For some aneurysms an endovascular approach may be possible. The technique involves placing a prosthetic graft into the aneurysm, rather than removing the aneurysm. By placing the endovascular graft inside the aneurysm, the blood is channeled through the graft, preventing pressure on the walls of the aneurysm and eliminating the risk of aneurysm rupture. Endovascular grafts are placed into the arteries in the groin through a small incision. Once inside the artery, the endovascular graft is advanced through the arterial system and positioned using X-rays for guidance. Typically, there are no chest incisions with endovascular aneurysm repair. Endovascular repair is usually done for aneurysms of the descending thoracic aorta and abdominal aorta. Aneurysms of the ascending aorta and aortic arch require an open surgical approach due to the branches present in these areas.