Rationale:~In patients with abdominal aortic aneurysms the Nellix Endoprosthesis aims to reduce post-operative complications and subsequent re-intervention rates. Using two stents covered with two polymer filled endobags used for sealing and excluding the aneurysm sac. Preliminary results show promising results in reducing these complications. The new endoprosthesis is not only different in treatment but also in follow up imaging. To date it is unknown how the stent, polymer filled endobags and aneurysm appear in CT imaging in short and long term follow up.~Objective:~To assess and describe the normal computed tomography (CT) appearance at 30 days and 1 year after implantation of the Nellix Endoprosthesis.~Study population:~Approximately a total of 100 patients who underwent endovascular aneurysm repair using Nellix endoprosthesis in three different hospitals. The population is comprised of approximately fifty patients from Rijnstate Ziekenhuis Arnhem and twenty-five each from St. Antonius Nieuwegein and St. Elisabeth Tilburg.~Design and methods:~The study is designed as a multicenter retrospective cohort. Using CT-scans from regular follow up dates (30 days and 1 year) imaging will be retrospectively assessed using medical imaging software. Main study endpoints are defined as followed:~Changes in the infrarenal neck morphology (below the renal arteries)~Changes in the thrombus in the aneurysm sac~Changes in the aneurysm wall and geometry~Changes in the cobalt-chromium stent and their lumen~Changes in the polymer-filled endobags Using anonymous patient data a database will be created an securely stored. Patient consent for study participation will be attained before accessing patient files.~Nature and extent of the burden and risk associated with participation, benefit and group relatedness:~The study will not bring an extra burden or risk for patients participating. Patients are encouraged to participate to improve insight for patients with the same disease and might improve health care in the future for this group of patients.
Multicenter retrospective CT follow up after aortic aneurysm repair using Nellix Endoprosthesis.