Surgery for aneurysm of the descending and thoracoabdominal aorta typically involves older, higher risk patients who may have hypertension, atherosclerosis, pulmonary obstructive disease (COPD), a history of smoking and some degree of existing kidney disease.
There are several techniques for surgery on this segment of the aorta. The "clamp and sew" method is the simplest, fastest approach, but has higher neurologic complication rate. Currently for elective surgery of the descending and thoracoabdominal aorta, the Comprehensive Aortic Program involves sequential aortic clamping with or without hypothermic circulatory arrest. Regardless of the technique used, the main consideration in surgery of the descending and thoracoabdominal aorta is always spinal cord and kidney protection.
- "Clamp and Sew" Method
- Partial Cardiopulmonary Support (Partial Heart-Lung Machine)
- Left Heart Bypass
- Total Circulatory Arrest Technique
"Clamp and Sew" Method
This technique has the advantages of simplicity, and there is less chance of coagulation problems. It is the fastest technique, but also has the highest complication rate for paraplegia, renal failure and embolization of sclerotic material to the visceral organs, lower extremities and kidneys. This is especially true if the ischemia time is above 30 minutes. Therefore, this technique is offered for a short-segment aortic pathology, when the operation is typically completed within 25 minutes.
Partial Cardiopulmonary Support (Partial Heart-Lung Machine)
With this technique, cannula are placed through the femoral vein and artery. A full dose of heparin is used, and the aorta is still clamped. This approach provides some protection to the spinal cord and kidneys. This technique may be used in combination with sequential aortic clamping technique.
Left Heart Bypass
In this approach, the patient's own lungs continue to function. Only the heart is bypassed. This technique can therefore be done with a low dose of heparin. Like the partial cardiopulmonary approach, there is risk of atherosclerotic embolization. This technique may be used in combination with sequential aortic clamping technique.
Hypothermic Circulatory Arrest Technique
This technique has minimized the risk of embolization while also providing maximum spinal cord protection. Using this technique, renal failure became extremely unlikely, and the risks are reduced. However, there is an increased risk of bleeding or pulmonary complications.