Management of Nellix migration and type Ia endoleak from proximal endovascular aneurysm sealing relining to late open conversion

Abstract

Background: Despite promising early results, midterm failures of the Nellix endovascular aneurysm sealing (EVAS) system (Endologix Inc, Irvine, Calif) have been reported at higher than expected rates. The management of proximal endoleaks and migration differs from those after conventional endovascular aortic aneurysm repair (EVAR) owing to the peculiar design of the Nellix device. In the present study, we report a monocentric experience in the management of EVAS complications using various techniques. We also performed a comprehensive review of the relevant literature on both open surgical and endovascular management of proximal failure of EVAS from the MEDLINE database.

Methods: We retrospectively analyzed the reinterventions for type Ia endoleak and migration after elective infrarenal EVAS at our institution. We collected preoperative, intraoperative, and follow-up data. Open and endovascular techniques are described. Overall survival, aortic-related mortality, and the technical success rate (rate of exclusion of endoleaks) with endovascular techniques were the primary outcomes.

Results: We performed 101 infrarenal elective EVAS procedures from 2013 to 2018. Of the 101 patients, 20 (19.8%) had required reintervention for proximal sealing failure. The indications were type Ia (Is2, Is3) endoleak, migration >5 mm, sac expansion >5 mm, and secondary rupture. Of the 20 patients, 6 (30%) were treated with endovascular techniques-2 with a chimney Nellix-in-Nellix application and 4 with proximal relining with a covered stent. The remaining 14 patients (70%) were treated with late open conversion (OC). The average time from EVAS to reintervention was 36.1 months (range, 3-65 months). Six patients (30%) had undergone OC in an emergent setting because of secondary rupture. The technical success rate for the patients treated with endovascular reinterventions was 100%. The 30-day mortality was 20% (4 of 20), all emergent cases (four of six emergent repairs; 67%). The overall survival for the 20 patients was 75% (n = 15) at a mean follow-up of 15.1 months (range, 2-47 months). One patient had died after 7 months of non-aortic-related causes.

Conclusions: The high reintervention rate of the Nellix graft mandates careful evaluation for its further use with the revised instructions for use, and it should not be used off-label. OC remains the strategy of choice when managing Nellix proximal sealing failures in fit patients. Chimney Nellix-in-Nellix application and transcatheter embolization are feasible alternative techniques. Proximal relining also appears to be an effective alternative to more complex interventions, although it requires further studies for validation.

Keywords: Abdominal aortic aneurysm; EVAS; Endoleak; Graft failure; Migration; Nellix.