Systematic review of risk factors and outcomes of post-implantation syndrome following endovascular aortic repair

OBJECTIVE:Post implantation syndrome (PIS) is an early systemic inflammatory response following endovascular aortic repair (EVAR). The response is variable in patients and the clinical significance of PIS upon outcomes is unknown. This study aims to evaluate the incidence, risk factors and prognostic implication of PIS. METHODS:Systematic literature review and analysis was performed in accordance with the PRISMA and Cochrane guidelines of PubMed, Scopus, ClinicalTrials.gov and the Cochrane Central Register of Controlled Trials. Eligible English-language studies regarding PIS after infrarenal EVAR were included, after removing duplicates. RESULTS:After screening, 31 studies were included. A total of 2,847 patients were reviewed with mean age of 70.7 years, of which 2012 (90.4%) were male with a pooled mean follow-up of 26.1 months. PIS was reported in 25.3% of cases with mean aneurysm diameter of 56.4 cm. PTFE grafts were utilized in 794 patients (27.9%) with polyester in 1839 (64.6%). WBC, CRP, IL-6, IL-8 and IL-10 levels were all significantly elevated postoperatively. Thirty-day outcomes included Type I endoleak rate of 0.8%, Type II endoleak 1.7%, reintervention 0.35% and mortality 0.25%. Subgroup pooled analysis of patients with PIS (309 patients) versus No-PIS (691 patients) revealed that polyester (642), rather than PTFE (234) grafts, were associated with a higher rate of PIS (94.8% vs. 3.7%; p = 0.0001), WBC count was higher in the PIS group both preoperatively (7.61 vs. 6.76; p = 0.04) and postoperatively (15.0 vs. 9.8; p = 0.0007) and IL-6 levels were higher in the PIS group postoperatively (98.6 vs. 25.2; p = 0.02). Aneurysm diameter and amount of chronic or new thrombus within the aneurysm sac was not identified as a risk factor for PIS. Pooled outcomes of patients with PIS vs. No-PIS demonstrated a significantly higher rate of 30-day mortality (0.6% vs. 0%; p = 0.03) and major adverse cardiac event (5.8% vs. 0.43%; p < 0.0001) without any differences seen in reintervention, 30-day Type I or Type II endoleak. CONCLUSION:This systematic review suggests that polyester grafts are strongly associated with PIS compared with PTFE. Interestingly, this report is suggestive of an association between 30-day mortality and major adverse cardiac events and PIS. Given these clinical sequelae, consideration for use of PTFE over polyester grafts to reduce the incidence of PIS may be a simple step to improve overall outcome. Further, exploration of the relationship between inflammatory mediators associated with PIS and mortality and cardiac complications may engender deeper understanding of risks, leading to eventual mitigation of harm for patients experiencing PIS.