Surgery for Aortic Aneurysms
Please see our Aortic Aneurysms overview page for a description of the anatomy and structure of the aorta. Aortic aneurysm surgery is complex and the techniques are very different for the different parts of the aorta. Surgery involves going on the heart-lung machine (cardiopulmonary bypass) and stopping the heart. The abnormal aorta is cut out and replaced with an artificial tube graft, usually made out of Dacron. The heart is then allowed to resume beating, and after it recovers, the heart-lung machine is no longer needed.
Ascending aorta
Ascending aorta are the easiest to treat. The ascending aorta is simply cut out and replaced with a graft.
Aortic root
The root is that portion of the aorta immediately above the aortic valve. As the root dilates, it can affect the aortic valve and cause it too leak. The root also contains the origins of the coronary arteries. The surgery usually involves removing the aortic valve, cutting off the origins of the coronary arteries, and removing the diseased aorta. A new aortic valve is put in along with a tube graft, and then the coronary arteries are reattached to the tube graft. This has been the standard practice for many years. However, if the aortic valve itself is normal, new techniques allow us to preserve the valve, avoiding all of the problems associated with artificial heart valves.
Aortic arch
These pose special problems. Normally, in aortic surgery, the aorta is clamped below the blood vessels to the brain and arms. The heart-lung machine can still run while the aneurysm is cut out, providing circulation to the brain and the rest of the body. However, with an aneurysm of the aortic arch, the origins of the blood vessels to the brain and arms are involved. Clamping them off during the aneurysm surgery would deprive them of blood. This would not likely be a problem for the arms, but would cause serious brain injury. Special techniques are required in this situation, and this involves putting the patient on the heart-lung machine and cooling the entire body down to a very low temperature.
Normal body temperature is about 37 degrees Celsius, and the patient is cooled to as low as 13 degrees Celsius. Once the brain and body are very cold, the heart lung machine is shut off, and during this time there is no circulation to the brain or body at all. The aneurysm is then cut out and the aorta reconstructed. When this is done, the heart-lung machine is restarted, and the patient is warmed back up to a normal temperature. When this is reached, the heart-lung machine is discontinued. With this technique, it may be possible to safely perform surgery for periods up to one hour with no circulation to the brain or body.