Nellix stent cannot be placed in patients yet.

Retrospective data have shown that active sac management, as applied in EVAS, reduces the incidence of the post-implant syndrome. All-cause and cardiac mortality at one-year seems to be lower after EVAS when compared to EVAR. Ongoing, low grade, inflammation could differ between techniques and induce cardiac damage.

This study is designed to establish whether EVAS results in a reduced post-operative inflammatory response during the first year after surgery, compared to EVAR as assessed by trends in circulating inflammatory cytokine concentration.

Study design: International prospective, comparative, explorative study. Study population: Patients scheduled to undergo infra-renal EVAR with a polyester endograft or EVAS for an infrarenal aortic aneurysm. This is an explorative study and therefore only patients who would normally receive a suitable device as part of standard treatment at the participating institutes will be recruited. Blood samples will be taken at specified time points before and after surgery.

Main study parameters/endpoints: The difference in early post-operative and long term inflammatory response between EVAS and EVAR, measured by the incidence of the post-implant syndrome. To investigate the incidence of the post-implant syndrome, the rise in CRP, WBC and circulating cytokines, at specified time points up to 12 months after surgery and the change in aortic thrombus volume and its relationship with the inflammatory response, measured by cytokines' concentrations.

Endovascular sealing of abdominal aortic aneurysms (EVAS) is a new technique to treat infrarenal abdominal aortic aneurysms (AAA), which can be performed more expeditiously than endovascular aneurysm repair (EVAR). The difference with EVAR is that fixation and seal are provided from polymer filled endobags that are placed in the aneurysmal sac. The post-implantation syndrome (PIS) is the clinical and biochemical expression of an inflammatory response following endovascular repair of an aortic aneurysm. More specifically, the presence of fever (body temperature >38 C for ≥1 day) and leukocytosis (white blood cell count (WBC) >12.000/mL) with negative blood cultures and is occurring in over 30% cases after EVAR. It is related to prolonged hospital stay and elevated CRP levels, that in turn increase the risk on major adverse cardiac events. The literature showed that the magnitude of the post-operative inflammatory response depends on the type of endoprothesis used for EVAR and that EVAS is related to a lower post-operative CRP level, lower white blood counts, a lower temperature and less cardiac complications compared to standard EVAR.

The current study was designed to explore the occurence of the post-implant syndrome after EVAR and EVAS. This study was also designed to unravel the cytokines which are involved in the post-implant syndrome after EVAR and EVAS.

In this international, prospective, explorative study 60 patients who are scheduled for EVAR and 60 patients who are scheduled for EVAS will be included. Blood samples (for WBC and circulating cytokines (TNF-α, Interleukin (IL)-1, 1RA, 6, 10, 18, CRP), Troponin T, HsTnT, NT-pro-BNP)) will be taken at:

• Before induction of anesthesia
• At wound closure
• 24 hours after surgery
• 48 hours after surgery
• 1 month after surgery
• 6 months after surgery
• 12 months after surgery

Patients are finished with the study after 12 months of follow-up.

Inclusion Criteria:

• Elective EVAR/EVAS
• Ability and willingness to provide written informed consent
• Age >50 years

Exclusion Criteria:

• Complex EVAR or EVAS, including iliac branched and supra-renal repairs (pre-planned visceral chimneys, fenestrations or branches)
• Ruptured or symptomatic AAA
• Planned internal iliac artery embolization
• Acute or chronic inflammatory illness (i.e. upper respiratory tract infection)
• Active rheumatoid arthritis
• Inflammatory bowel disease, etc.)
• Inflammatory and mycotic aneurysms
• Planned associated surgical procedure (i.e. iliac conduit, femoral endarterectomy, etc.)
• Previous aortic surgery (open or endovascular)
• Untreated malignancy
• Major surgery six weeks before EVAR/EVAS
• Ongoing or recent immunosuppressive treatment, including corticosteroid use

No masking since patients, doctor and researchers know if patients undergo EVAR or EVAS.