Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3850_Библиотеки_им_академика_М_И_Перельмана

Nevertheless, we will attempt, in this chapter, to dis­cuss the ongoing studies and the need for future studies to better understand and treat the various thoracic aor­tic pathologies.

either eliminated or greatly reduced. Furthermore, the diameter reduction after complete aneurysm exclusion is probably less than in the abdomen combined with the use of an oversized device (at least 10% more than the normal aortic diameter) and this reduces risks even more. Nevertheless, the most frequent thoracic compli­cations are type8I endoleaks that occur at aortic and graft junctions allowing the aneurysmal sac to remain pressurized. They are more frequent because degenera­tive thoracic aortic disease is usually more diffuse than abdominal disease; thus, progression of the malady at attachment sites is more likely. To avoid this problem, we recommend the placement of longer stent grafts cov­ering healthy aorta up to the visceral arteries. Type II endoleaks, except from the left subclavian artery, are rare. If two or more grafts are used, type III endoleaks can arise at junctions, requiring insertion of another stent-graft segment. This complication is greatly re­duced when we systematically overlap a long segment of the grafts. Finally, pseudoaneurysms and intimal per­forations at distal implementation sites have been re­ported secondary to stent-graft erosions [4]. Complete long-standing studies are still needed to determine the incidence of these complications and their long-term ef­fects.

As devices improve, better results should be ob­served in the future. Therefore, requests to place endo­grafts in patients with small lesions, in which the risk of rupture is extremely low, should be more frequent. It will be important to resist these demands until further data prove otherwise. So, as far as we are concerned, we recommend that endograft use should be limited to patients who truly exhibit surgical indications.

Despite the frequency of acute aortic dissection, there are few large series published on the outcomes of dis­sections and most are long retrospective multicenter studies confounded by inconsistent methods of treat-

complicated acute type B aortic dissections. The aim of this multicenter randomized controlled clinical trial is to evaluate the 1-year outcomes, including complication rates and quality of life, of patients with type B dissec­tion treated either percutaneously or medically. Early results can be expected in 2005.

Other concerns include the timing of the interven­tion and the length of coverage necessary to exclude the false lumen.

and total shrinking of the aorta over the stent graft were seen in all cases.

However, controversy remains regarding the best method of management. Studies must be carried out to determine the precise place of endovascular treatment in the management of acute rupture of the thoracic aor­ta. An ideal study would compare the outcomes of pa­tients of similar health status subjected to conventional surgical intervention, to stent-graft placement or to medical treatment. Unfortunately, such a prospective study is not feasible for ethical reasons; patients incap­able of undergoing conventional surgery for any reason should of course not be operated. Additionally, since a small number of patients receive treatment in each cen­ter, even a multicenter randomized study comparing the two treatment methods is illusive. A prospective regis­try evaluating patients considered unfit for surgical in­tervention because of comorbidities treated with or without stent-graft placement would best assess the ef­fect of the endovascular strategy compared with that of medical treatment. In order to do so, we suggest the creation of an international registry similar to the one for aortic dissections to compile the results of endovas­cular treatment and consequently help to define its in­dications.

Thoracic aortic stent-grafts were not as frantically marketed as abdominal ones, and were initially limited

to three types: the first-generation Stanford homemade stent-grafts and two industrially made ones, Medtronic's Talent and Gore's Excluder. This allowed relatively homogeneous international registers to be built up, avoiding the potential bias due to excessively different devices. This controlled maturity allows past experience to be taken into account for clinical evaluation research to develop new concepts, such as a better fitting to arch lesions or related to stent coating.

l Dissection