Background and aims:
Activation of the systemic inflammatory response (SIR) is associated with inferior outcomes across a spectrum of disease. Routinely available measures of the SIR (neutrophil:lymphocyte ratio (NLR), platelet:lymphocyte ratio (PLR), systemic immune-inflammatory index (SII), systemic inflammatory grade (SIG)) have been shown to provide prognostic value in patients undergoing surgical intervention. The present study aimed to review the literature describing the prognostic association of NLR, PLR, SII and SIG in patients undergoing intervention for abdominal aortic aneurysm (AAA).

Methods:
This PRISMA guidelines were followed. The MEDLINE database was interrogated for relevant studies investigating the effect of peri-operative systemic inflammation-based prognostic systems on all-cause mortality in patients undergoing OSR and EVAR for AAA. Inter-study heterogeneity precluded meaningful meta-analysis; qualitative analysis was instead performed.

Results:
There were 9 studies included in the final review reporting outcomes on a total of 4571 patients; 1256 (27 %) patients underwent OSR, and 3315 (73 %) patients underwent EVAR. 4356 (95 %) patients underwent a procedure for unruptured AAA, 215 (5 %) patients underwent an emergency procedure for ruptured AAA0.5 studies reported early (inpatient or 30-day) mortality; 2 of these found that elevated NLR predicted inferior survival, however PLR did not provide prognostic value. 6 studies reported long-term mortality; elevated NLR (5 studies), PLR (1 study), and SIG (1 study) predicted inferior survival.

Conclusions:
It appears that activation of the SIR is associated with inferior prognosis in patients undergoing intervention for AAA, however the evidence is limited by heterogenous methodology and lack of consensus regarding optimal cutoff.

Prospero database registration number:
CRD42022363765.