For surgery on the ascending aorta, aneurysms can form as a result of aortic valve disease and/or simply because the segment of the aorta shortly after it leaves the heart, dilates. There are very seldom symptoms associated with these aneurysms and most often they are a finding that is concomitant with aortic valve disease or simply the appearance of the aneurysm on a routine X-ray examination.

Size and the occurrence of symptoms such as pain or mini strokes are determining factors for surgical intervention and this is usually done with the use of the heart-lung machine. This may require replacement of the ascending aorta with a prosthetic Dacron tube and/or concomitant replacement of the aortic valve. In such instances, it is also necessary to reattach the coronary arteries that are the blood supply to the heart muscle and this is accomplished by suturing them to the Dacron graft.

Surgery for the aortic arch is more complex because the blood supply to the arms, head, neck and brain originates on the aortic arch and protection of the central nervous system is very important.

Dr. Bell-Thomson uses a deep hypothermic circulatory arrest for protection of the brain along with a protocol of pharmacologic neuroprotection. The patient is normally cooled on the heart-lung machine with a heat exchanger to a temperature below 20 degrees centigrade. The circulation is stopped for the length of time that it takes to reattach the head vessels to a Dacron graft, which would replace the arch portion of the aorta. On occasion, this becomes an extension of surgery for replacement of the ascending aorta.

Surgery for the descending thoracic aorta usually involves the presence of aneurysms that do not necessarily create symptoms until they are large enough to compress adjacent organs or structures and/or are discovered incidentally on x-ray examinations of the chest. These require replacement of the aneurysm with a prosthetic Dacron tube. However, the most important aspect of this surgery is the protection of the spinal cord thus preventing the occurrence of the worst possible complication – paraplegia or paralysis from the waist down.

Dr. Bell-Thomson has always used monitoring of the spinal cord by assessing the transmission of somato-sensory cortical-evoked potentials, which means that an electrical impulse is provided to the legs and sensed on the scalp to determine that the integrity of the spinal cord remains intact throughout the period of reconstructive surgery for the thoracic aorta. A pharmacological neuroprotection protocol is also instituted during these procedures.

Another contributing factor to a successful outcome is that Dr. Bell-Thomson always uses some form of distal perfusion for the lower half of the body, which is important to maintain during the period of repair and reconstruction of the descending thoracic aorta.

Occasionally these aneurysms do extend into the abdomen as thoracoabdominal aneurysms that require a similar surgical approach and correction. However, the incision will extend from the chest into the abdomen to allow access to the visceral arteries that need to be reimplanted on the Dacron graft prosthesis.

Despite the use of intravascular stents for the treatment of abdominal aortic aneurysms, there are still indications for a surgical approach in preference over a percutaneous technique and Dr. Bell-Thomson has extensive experience in replacement of the abdominal aorta for the treatment of abdominal aortic aneurysms.