# Inflammation-Based Cell Ratios Beyond White Blood Cell Count for Predicting Postimplantation Syndrome After EVAR and TEVAR

## TL;DR

This study explores how preoperative inflammation markers like SIRI and ELR can predict postimplantation syndrome after aortic stent-graft procedures.

## Contribution

The study introduces SIRI and ELR as novel preoperative predictors of postimplantation syndrome beyond traditional white blood cell counts.

## Key findings

- PIS occurred in 18.3% of patients and was associated with younger age, larger aneurysm diameter, and greater mural thrombus thickness.
- Preoperative SIRI and CRP were significantly higher in patients who developed PIS, while ELR and albumin were lower.
- EVAR procedures and elevated SIRI were independently associated with increased PIS risk.

## Abstract

Postimplantation syndrome (PIS) is an early inflammatory response following endovascular stent-graft implantation (EVAR and TEVAR), defined by culture-negative fever and leukocytosis. The patient’s preoperative inflammatory status is thought to play a central role in its development. This study aimed to evaluate whether the systemic inflammatory response index (SIRI) and the eosinophil-to-lymphocyte ratio (ELR) can serve as preoperative predictors of PIS. Clinical data from 300 patients who underwent aortic endograft implantation and laboratory results obtained 24 h before the procedure, and at 24 h, 72 h, and 1 week postoperatively, were prospectively recorded. PIS was defined as culture-negative fever ≥ 37.8 °C accompanied by leukocytosis ≥ 12,000/µL. Inflammation-based indices derived from complete blood count (SIRI and ELR), along with serum C-reactive protein (CRP) and albumin levels, were compared between patients with and without PIS. Logistic regression and receiver operating characteristic (ROC) analyses were performed to identify independent predictors. PIS developed in 55 patients (18.3%). Patients with PIS were younger (70.1 ± 8.6 vs. 72.7 ± 7.3 years; p = 0.042) and had larger aneurysm diameters and greater mural thrombus thickness. Preoperatively, leukocyte count, SIRI, and CRP levels were significantly higher in patients who developed PIS, whereas ELR and albumin levels were lower. Multivariable analysis showed that a larger aneurysm diameter (OR: 1.2; 95% CI: 1.0–1.3; p = 0.003), greater mural thrombus thickness (OR: 1.3; 95% CI: 1.0–1.6; p = 0.012), EVAR procedure (OR: 3.7; 95% CI: 1.2–6.3; p = 0.033), elevated SIRI (OR: 1.9; 95% CI: 1.2–3.1; p = 0.005), and higher CRP (OR: 1.4; 95% CI: 1.1–3.2; p = 0.003) were significantly associated with PIS. In contrast, increasing age, higher ELR, and higher albumin levels were associated with a reduced risk of PIS. Simple biomarkers routinely obtained from standard laboratory tests can contribute meaningfully to the preoperative prediction and postoperative identification of PIS. Their integration into risk stratification models and confirmation against definitive diagnostic criteria will require validation in larger, multicenter studies.