Indications for thoracoabdominal aortic surgery

Abstract

The thoracoabdominal aorta involves varying portions of the thoracic and abdominal aorta. However, problems embracing the thoracoabdominal aorta might already start at the level of the aortic root, the ascending aorta, or the aortic arch, as is often the case in postdissection thoracoabdominal aortic aneurysms (TAAAs). Proximal aortic dissection (ie, DeBakey type I) by definition extends into the more distally located aortic segments. Classification of aortic pathology, whether aneurysm or dissection, is of the utmost importance because operative risks, surgical approach and strategy, and, of course, the extent of the repair are dependent on the type of TAAA. TAAAs were first classified by Crawford and colleagues into 4 types and are shown in Figure 1. Type I aneurysm involves the aorta distal to the left subclavian artery and extends down to the proximal suprarenal abdominal aorta. A type II aneurysm is the most extensive, and it involves the descending thoracic aorta distal to the left subclavian artery and extends into the infrarenal abdominal aorta. A type III aneurysm starts in the descending thoracic aorta below the level of T6 and extends below the renal arteries. A type IV aneurysm starts at the diaphragm (not above) and involves the complete abdominal aorta, and its approach is similar to that of the other types. Also, aortic dissections should be classified according to the Stanford classification, DeBakey classification, or both to analyze and compare outcomes, results of surgical intervention, and follow-up. In at least 25%of cases, but probably more, dissection results in future aneurysmal dilatation, finally ending as so-called postdissection aneurysms. Repair of the thoracoabdominal aorta is a major surgical challenge, with a high morbidity and a significant mortality. Therefore it is warranted in all elective situations to assess the effect of surgical intervention by evaluating the pulmonary, cardiac, renal, and neurologic risks. It is possible to calculate the risk of rupture by using equations, including certain risk factors. In the elective context there is enough time to prepare and optimize all organs at risk: cessation of smoking, use of bronchodilators and respiratory exercise