Post-Implantation Syndrome Incidence is Higher After Complex Endovascular Aortic Procedures Than After Standard Infrarenal Repair

Post-implantation syndrome (PIS), characterised by malaise, fever, and increased inflammatory markers, is a common occurrence after endovascular aneurysm repair (EVAR), causing prolonged hospitalisation and increased cost. This study aimed to determine the incidence and short-term outcomes of PIS after fenestrated or branched procedures in aorto-iliac aneurysms compared with standard EVAR.A retrospective, comparative study from a tertiary academic institution was undertaken. All patients who underwent elective EVAR with polyester stent grafts from January 2015 to June 2021 were considered. Two groups were defined: standard EVAR (sEVAR) and complex EVAR (cEVAR). The latter included visceral fenestrated and branched or iliac branch and chimney stent grafts. The primary outcome was the incidence of PIS within three days of the index procedure. Secondary outcomes were short-term complications and risk factors for PIS. A multivariable model was constructed to correct for confounders.Overall, 253 patients were included: 165 (65.2%) sEVAR and 88 (34.8%) cEVAR. Complex EVAR patients were younger, with larger aneurysms, had longer procedures, and were more likely to have intra-operative complications. The PIS incidence was 23.7% (n = 60), significantly higher in cEVAR (34.1% vs. 18.2%; p = .005) and increased with the complexity of the procedure (EVAR: 18.2% vs. EVAR + iliac branch device: 25.0% vs. fenestrated and branched EVAR: 36.2%; p = .030). On multivariable analysis, cEVAR (OR 2.833, 95% CI 1.295 - 6.198; p = .009) was associated with a significantly increased risk of PIS. No differences in short term outcomes according to PIS status were noted. Group sub-analysis for cEVAR patients did not reveal any statistically significantly different outcomes according to PIS occurrence.In this cohort, cEVAR procedures were associated with a significantly increased risk of developing PIS compared with standard infrarenal repair. Post-implantation syndrome also appears to have a benign course with no major impact on peri-operative outcomes after cEVAR. Further research to confirm these findings is required.