IYSC11 - Stent Graft Migration in TAAA Repair: The Role of Fixation Techniques

Objectives: Endovascular aortic repair with fenestrated and or branched stent grafts (F-/BEVAR) has become the standard treatment for thoracoabdominal aortic aneurysms (TAAAs). These procedures involve combinations of several aortic stent graft components. Movement between these components can ultimately result in loss of attachment, stent graft separation and type IIIa endoleak, with risk of sac expansion and rupture if left untreated.
Aortic stent graft attachment is achieved through either active fixation, using barbs to connect grafts, or non-active fixation, which relies on stent-to-stent friction. This study aims to compare outcomes following the use of these fixation techniques in endovascular thoracoabdominal repair.

Methods: Fifty-four consecutive patients treated with F-/BEVAR, and at least one TEVAR, for TAAA’s during the period 2013-2022 were included. Five were excluded due to missing follow-up CT-scans, and one was excluded because the extensive number of TEVAR endografts rendered measurements unreliable. Postoperative CT scans at 30 days and the latest follow-up were analyzed in a core lab. The F-/BEVAR components were all custom made devices or T-branch (Cook medical, Bloomington, Indiana). Migration was analyzed in the overlap zone between the most distal TEVAR (Cook devices) and the F-/BEVAR.
Patients were grouped by fixation technique (active vs. passive) of the F-/BEVAR. Stent graft migration was the primary endpoint, with target vessel instability (TVI) reintervention as the secondary endpoint.

Results: Baseline data are shown in Table I. Follow-up time showed no significant difference (p=0.788). Migration per year was 0.79mm (IQR 0.29-1.6) in the active and 3.16mm (IQR 0-5.5) in the passive fixation group (p=0.054, see Fig 1). Multiple linear regression analysis showed a significant effect of fixation technique on migration (p = 0.003), while other clinically relevant variables did not reach statistical significance. Logistic regression, with a migration cutoff >10mm, revealed an odds ratio of 21 for passive fixation (p = 0.014).
In secondary analyses, reintervention rates were examined using generalized estimating equations. Fixation technique did not significantly affect reintervention for TVI (p = 0.547). However, migration itself was associated with a significant risk of reintervention (p = 0.043). One rupture and four aortic reinterventions (18%; p=0.038) occurred exclusively in the passive fixation group.

Conclusions: These findings suggests that fixation technique affects the outcome after endovascular thoracoabdominal aortic repair. Passive fixation may increase the risk of stent graft migration, which could lead to endoleak, rupture, and increased reintervention rates for TVI. Larger multicenter studies are needed to confirm the clinical relevance of these observations.