Early and mid-term outcomes of a novel Endovascular Aneurysm Sealing (EVAS) system in patients with infrarenal Abdominal Aortic Aneurysms.

BACKGROUND: Endovascular aneurysm sealing (EVAS) using the Nellix system is a promising technology for Abdominal Aortic Aneurysm (AAA) treatment. Long-term data is unavailable regarding the potential modifications of the EndoBags and their content, and the polymer behavior over time. We present our initial clinical experience with this sac anchoring endoprosthesis in 24 patients with a maximum 12 months follow-up. METHODS: From December 2013 to March 2015, 24 patients with an infrarenal AAA were treated with the Nellix™ System. Computed tomography angiography (CTA) scan control was performed at 30 days, and follow-up magnetic resonance angiography (MRA) and ultrasounds were performed at 30 days, 6 and 12 months. Median and peak systolic velocities in the suprarenal aorta were measured preoperatively and during follow-up using phase contrast sequences and Argus (Siemens, Erlangen, Germany) software of the MRA. RESULTS: We achieved 100% technical success, 0% aneurysm-related mortality and 0% endoleaks. One patient (4%) experienced early acute thrombosis of a single Nellix stent, successfully treated with thrombolysis. Sac shrinkage occurred in 80% of cases with 12-months follow-up. CONCLUSIONS: Our preliminary clinical experience is promising, with 100% early technical success and satisfactory sealing of the aneurysm sac. Postprocedural controls during 1-year follow-up revealed no morphologic changes of the aneurysm wall, stable device and endobag position, and gradual dissolution of the air initially trapped within the EndoBags. Aneurysmal sac shrinkage occurs and probably is due to the remodeling of the thrombus around the EndoBags and the dissipation of the air bubbles into the EndoBags.