Curative replacement of the dissected aortic arch: a new insight to resolve an old question 'how extended should the arch repair be?'

Abstract

I read with great interest the paper by Tsagakis et al. suggesting that the extent of dissection exactly reflects the late outcome after surgery of acute type A aortic dissection [1]. Almost 40% of their patients suffered aortic dissection limited to the ascending aorta and aortic arch. In 18% of them, classical-type DeBakey II dissection was diagnosed, and in 82% the aortic arch was involved in the dissection. However, the complete arch replacement was performed in only 36%, indicating that a complete resection of all the dissected aortic wall was not performed in all patients. Although there were no late aortic events during the follow-up of 5 years, distal complications like redissection or false aneurysm formation can occur beyond such a time range, especially when only a limited part of the dissected aortic wall remains in place. Nevertheless, the observations of Tsagakis et al. correspond with our experience in which a curative replacement of all dissected aorta was technically possible in almost 50% of patients with acute type A aortic dissection [2]. Besides the dissection of the proximal aorta in which the dissection does not extend beyond the aortic isthmus, isolated arch dissection or arch and descending aorta dissection without involvement of the ascending aorta can be observed, and therefore, as a surgical consequence of those pathologies, we proposed a classification that takes into consideration the extent of dissection (D) and the location of the intimal tear (E) in three main segments of the aorta (a—ascending aorta, b—aortic arch, c—descending aorta) [2]. Thus, there are several subgroups of type A dissection that are relevant from a surgical perspective. In the group (D-a; E-a), which corresponds to the DeBakey Type II classification and contains about 10–20% of patients, the dissection is limited exclusively to the ascending aorta and aortic arch replacement is not necessary unless there is another indication for doing it. About 20–30% of patients present aortic dissection that extends from the ascending aorta through the entire arch reaching approximately to the level of aortic isthmus (D-ab, mostly combined with E-a). In such cases, complete arch replacement ensures curative resection of all dissected aortic wall. Because during the follow-up time of up to 16 years no patient with this subtype of dissection suffered any aortic event after complete arch replacement in our experience, I am convinced that this approach is an appropriate one and should be the goal. Regarding Tsagakis’s paper, I would like to add that it is actually not the distal extent of dissection but, as a consequence of it, the extent of surgery that reflects the late outcome and the risk of distal aortic events. Given the continuing controversy on how extended arch repair should be performed, their paper supports again the need for dividing the aortic arch within common classifications, which can, by using meta-analyses, shed more light on the choice of proper surgery and prediction of results.