What is the Aorta?
The aorta is the main artery of the body all the other arteries lead off from it. From the heart it runs upwards (ascending aorta), then turns in the aortic arch downwards (descending aorta) and divides at roughly hip height into the pelvic arteries. In Germany aortic procedures represent about 12 percent of all operations using the heart-lung machine. The number of aortic operations is increasing, mainly due to the longer life expectancy of the population.
Common Diseases of the Aorta
The most frequent reasons for an operation on the aorta are so-called aneurysms or dissection.
An aortic dissection is a split between the three wall layers of the aorta, generally caused by a tear in the inner layer. Blood penetrates the space between the layers and increases it even further. This is a life-threatening situation. An aneurysm is an enlargement or bulge of the aorta. The causes are degenerative changes (arteriosclerosis), congenital connective tissue weakness or inflammation.
Most aneurysms of the aorta cause no symptoms and are therefore only discovered by chance during an examination. Only when an aneurysm has become very large does it produce symptoms such as nerve damage, circulatory disturbances or shortage of breath. If an aneurysm is more than five centimeters in diameter patients are usually advised to have it operated on. The reason for this is the high risk of a tear in the aortic wall, known as aortic rupture, which would allow blood to surge into the surrounding tissue.
If a large amount of blood penetrates a body cavity such as the pericardium (heart sac) the rupture often leads to death. The mortality during and after an emergency operation is considerably higher than with a planned procedure. It is therefore particularly important that patients with an enlargement of the aorta measuring less than five centimeters are examined regularly. In some cases the surgeons advise an operation when the diameter is lower than this.
Treatment
In operations for aortic aneurysms and dissections the diseased part of the vessel is replaced by a prosthesis. Usually the prosthesis is made of synthetic material. If the aorta or the surrounding tissue is infected, a homograft (aortic segments removed during organ donation) or biological prosthesis, made from pericardial tissue, may be used. The German Heart Center Berlin performs over 400 aortic operations each year. Specialized surgeons decide on the optimal means of treatment for each patient.
Conventional Operation
The type of operation depends on which segments of the aorta are affected. In the case of aneurysms close to the heart or of the aortic arch, the breastbone is severed and the patient’s chest is opened up. The descending part of the aorta is reached via an incision between the ribs. If the abdominal aorta is also affected, the incision is extended to the abdominal wall. When the aneurysm of the abdominal aorta is below the renal arteries, access is gained by opening the abdomen. With some operations the heart-lung machine takes over the function of both these organs.
Minimally Invasive Operations
Today many aneurysms can be treated with so-called endoprostheses without conventional surgery being necessary. The prosthesis is introduced into a groin or arm vessel, advanced as far as the site requiring treatment and unfurled there. Doctors at the German Heart Center Berlin have contributed to the development of numerous novel operation procedures for aortic surgery.