The post-implantation syndrome(PIS). The impact of different devices for endovascular abdominal aortic aneurysm repair (EVAR) and related etiopathogenetic implications

Introduction:Postimplantation syndrome (PIS) is a systemicinflammatory response occurring in an early phase afterendograft implantation in patients treated for abdominal aortic aneurysm (AAA).The pathophysiology underlying PIS is not yet well under-stood. It is speculated that the type of the stent graft or themural thrombus within the AAA may play a role indeterming this inflammatory response.At present, there is also no consensus on its effect onclinical outcomes during follow-up.The endovascular aneurisys sealing (EVAS) with the Nellixsac-anchoring endoprosthesis (Nellix Endovascular, PaloAlto, Calif) obliterates the sac thus preventing the newonset of thrombus in the aneurysm sac.The primary aim was to evaluate the incidence of post-implantation syndrome associated with EVAS using Nellixsystem compared with EVAR and the possible inherentpathogentic implications related to the lack of new muralthrombus after EVAS. Secondary aims were to assess theeffect of endoskeleton AFX (Endologix) device comparedwith other commercially available exoskeleton PTFE stentgrafts on the inflammatory response. Finally, we analyzedthe potential association of PIS with the clinical post-operative ouctcomes.Methods:From November 2013 to September 2017, 60AAA patients were treated with EVAS using the Nellix sys-tem (mean age 729 years;) and 110 patients were sub-mitted to EVAR: 56 AFX devices and 54 other PTFE stentgrafts (mean age 7410 years) at a single center and wereretrospectively reviewed.The diagnosis of PIS should fulfill at least two of thefollowing criteria: body temperature>38C and leukocytecount>12,000/mL and rise of serum C-reactive protein.These parameters were serially assessed before EVAR andpostoperativelyResults:The implantation of Nellix system was associatedwith lower incidence of PIS when compared to EVAR usingAFX device and other endografts (8.3%, 30%, 35%, respec-tively, p-value¼0,0008555). We did not observe a statisti-cally significant difference in the incidence of this systemicinflammatory response after endoskeleton AFX devicedeployment compared with other EVAR exoskeleton PTFEstent grafts. Early and mid-term complications were pro-portionally less frequent after EVAS (10.3%) than after EVARand after EVAR using AFX device (8.9%) than after EVARwith other PTFE stent grafts (16.4%) but these differenceswere not statistically significant (p¼0.43).During follow-up (mean 24 months), adverse outcomesrates did not significantly differ in patients with and withoutPIS (8.0% vs 13.4% p¼0.43)Conclusion:Implantation of Nellix stent graft seems to haveless effect on PIS than EVAR devices. The lower inflamma-tory reaction observed after EVAS might be related to theendobags of Nellix system which completely seal theaneurysm sac reducing the new-onset of mural thrombus.This could confirm the role of new-onset mural thrombus inthe genesis of PIS.The systemic inflammatory response does not significantlydiffer after endoskeleton AFX device deployment comparedwith other EVAR exoskeleton stent grafts.PIS does not seem to have any significant prognostic im-plications in terms of early and mid-term major adverseevents.Disclosure:Nothing to disclosere