LIMITATIONS
This study is limited by its retrospective nature and by referral bias
inherent in a single specialty center study. Statistical significance of
predictors of adverse outcome could not be achieved due to low number of
adverse events and overall relatively small cohorts. The results
reported in this study are representative only of referral centers with
concentrated experience in these procedures.
Despite advantages in the approach to the mega-aorta, there are also
certain inherent disadvantages of the Two-Stage elephant trunk
procedure. (a) Stage I requires a suitable landing zone in the aortic
arch for the elephant trunk anastomosis. Although workable neck is
usually able to be found, this can be problematic in the advanced mega
aorta. In our practice, we use the Sienna graft for such cases; the
Sienna graft has a “skirt” that can accommodate virtually any aorta.
(b) The elephant trunk can be difficult to engage at a second stage
endovascular completion. We have uniformly used an open second stage.
Also, grafts are now available in Europe (E-Vita (Jotec) and Thoraflex
(Terumo)) and under investigation in the United States that can be
deployed at the time of the original procedure to stent the descending
aorta (albeit incurring a risk of paraplegia with all but the shortest
grafts)[16].