Neutrophil-to-Lymphocyte Ratio as Potential Marker of Outcome in Popliteal Artery Aneurysm Repair

Abstract

Objective: The neutrophil-lymphocyte ratio (NLR) is an inexpensive and easily available inflammatory marker for cardiovascular disease. The aim of the present study is to evaluate a possible association between preoperative NLR value and popliteal artery aneurysm (PAA) repair outcomes. Methods: A single-center retrospective study on all patients, who underwent urgent or elective PAA repair from June 2010 to October 2022, was performed. Study outcomes were immediate technical success, 30-day and mid-term primary patency, reintervention, limb salvage, and mortality rates. The NLR was calculated by dividing the absolute neutrophil count by the absolute lymphocyte count, and, according to the literature, a cut-off of five has been considered as a possible threshold for the analysis. Results: Eighty-two patients (80 male) with a total of 97 popliteal artery aneurysms were enrolled in this study. The mean preoperative NLR was 2.9 ± 2.4. In 10 (10.3%) PAAs, the NRL was >5 (High-NLR group), and, in the remaining 87 (89.7%), the NLR was <5 (Low-NLR group). The preoperative NLR for urgent procedures was higher than elective cases (4.37 vs. 2.30; p < 0.001). However, no significant differences were found as far as immediate 24 h technical success (p = 0.48) and 30-day primary patency (p = 39). At mean follow-up, the primary patency rate was significantly higher in the Low-NLR group (p = 0.0044), without statistical differences for re-operation (p = 0.27), limb salvage (p = 0.09), and mortality rates (p = 0.51). The Kaplan-Mayer analysis showed a significant difference in freedom from major amputation in patients with an NLR > 5 compared to the ones with an NLR < 5 (p = 0.038), without any differences in terms of survival, primary patency, and the need for reintervention rates. The multivariable Cox regression analysis identified the NLR value as an independent predictor of better outcomes regarding freedom from the amputation rate (p = 0.25). Conclusions: Our experience indicates that a preoperative NLR value > 5 can identify high-risk patients affected by a PAA and may negatively influence the surgery's long-term outcomes. Therefore, this selected group of patients could need a more tailored approach and closer monitoring over time.

Keywords: inflammation; neutrophil to lymphocyte ratio; popliteal artery aneurysm; vascular outcomes.

Figure 1

Estimated long-term freedom from any adverse events evaluated by Kaplan–Mayer curve analysis and log-rank test according to baseline NLR value in terms of primary patency (A), survival (B), freedom from major amputations (C), and need for reintervention rates (D).