Endovascular aneurysm repair (EVAR) is associated to a systemic inflammatory response called post-implantation syndrome (PIS) in a significant proportion of patients. This is characterized by constitutional symptoms, fever and elevated inflammatory biomarkers occurring in the early perioperative period. Endograft material has been consistently associated with PIS risk, in particular woven polyester endografts, with a higher risk of PIS when compared to non-polyester endografts. Some post-operative and short-term consequences have been associated to PIS. In the short-term PIS leads to a longer hospitalization period, increased risk of early readmission and a possible increase in adverse cardiovascular events. Fenestrated/branched EVAR (f/bEVAR) and iliac-branched devices (IBD) involve longer procedures with greater vessel manipulation, more aortic coverage and a generally higher area/volume of endograft implanted, but their relationship with PIS is scarcely reported in the literature. This study aimed to determine the incidence and short-term clinical consequences of PIS after implantation of f/bEVAR and IBD endografts in aorto-iliac aneurysms, comparing to standard EVAR.

The authors present a single center, retrospective cohort study. All consecutive patients who underwent elective endovascular repair of thoracoabdominal, abdominal and aorto-iliac aneurysms with polyester endografts between 2015-2020 were considered. Urgent cases, implantation of isolated iliac branch devices, mycotic or inflammatory pathologies, aorto-enteric or aorto-venous fistulas and off-label techniques were excluded. Data concerning baseline characteristics, aneurysm anatomy, procedure-related data, and postoperative course, including vital signs, laboratory results, postoperative complications and death were obtained. Post-implantation syndrome (PIS) was defined as tympanic temperature >38ºC and CRP>75 mg/L, after excluding complications with an effect on inflammatory markers. Two groups were created: complex EVAR (b/fEVAR and/or EVAR+IBD) and standard EVAR. Primary endpoint is the occurrence of PIS. Secondary endpoints were short-term complications of PIS vs non-PIS patients and risk factors for PIS incidence. Univariable (Pearson´s chi square test, Student t-test) and multivariable (logistic regression) analyses were implemented to examine the outcomes.

Two-hundred and twenty-two patients (94.1% male) were included in the analysis: 148 (66,7%) standard EVAR and 74 (33.3%) complex EVAR (12 EVAR+IBD and 64 b/fEVAR). Patients who underwent complex EVAR were younger (70 vs 74yo, p=0.001), had larger aneurysms (63mm vs 56mm, p=0.004) and were more frequently medicated with beta-blockers (47% vs 33%, p=0.03). Complex EVAR procedures were longer (240min vs 120min, p=0.001) with more use of fluoroscopy (74min vs 22min, p=0.001), iodinated contrast medium (160mL vs 90mL; p=0.001) and with higher blood loss (300mL vs 150mL, p=0.001). (Table 1) Thirty-one percent (n=23) of complex EVAR were endovascular aortic reinterventions. Total PIS incidence was 23.9% (n=53) and was significantly higher in complex EVAR (36.5% vs 17.6%, p=0.002). PIS incidence increased as the complexity of the procedure increased (EVAR: 17.6% vs EVAR+ IBD: 33.3% b/fEVAR: 38.7%; p=0.005). Hospitalization was longer (8 days vs 5 days, p=0.001) and reinterventions and mortality were also higher in complex EVAR (17.6% vs 2.0%, p=0.001 and 6.8% vs 1.4%, p=0.037, respectively). (Table 2) On logistic regression, antiplatelet use was associated to a reduced risk of PIS (OR 0.362; 95% CI 0.142-0.918; p=0.032) and higher procedure duration associated to a higher risk of PIS (OR 1.011, 95% CI 1.003-1.018, p=0.001). On multivariate analysis, complex EVAR were associated to a higher risk (OR 2.241; 95% CI 0.979-5.128; p=0.056) and endovascular aortic reintervention with a lower risk of PIS, (OR 0.367; 95% CI 0.342-1.410; p=0.087), both without statistical significance. PIS was not associated with increased risk of early complications or mortality.

In this cohort of elective endovascular aneurysm repair with polyester grafts, complex EVAR is associated with increased incidence of PIS, prolonged hospitalization, higher reinterventions and mortality rates at 30 days. However, the occurrence of these outcomes did not seem related to PIS occurrence. The higher incidence of PIS in complex EVAR is probably multifactorial and may also reflect variables not covered in this study.

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