Preoperative Neutrophil to Lymphocyte Ratio, Platelet to Lymphocyte Ratio, and Mean Platelet Volume as Predictors of 1-Year Mortality in Patients Undergoing an Open Repair of Abdominal Aortic Aneurysms: A Retrospective Study

Abstract

Objectives: To investigate if preoperative neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), or mean platelet volume (MPV) could be used to predict 1-year mortality in patients undergoing open abdominal aortic aneurysm (AAA) repair.

Methods: We retrospectively reviewed 382 patients who underwent open AAA repair between January 2008 and July 2019. We divided the patients into two groups based on 1-year mortality and compared the preoperative NLR, PLR, and MPV. The patients were then classified into tertiles based on their preoperative NLR (first tertile: <2.41 (n = 111); second tertile: 2.41 ≤ NLR ≤ 6.07 (n = 111); and third tertile: >6.07 (n = 112)). We compared the incidence of mortality and morbidity across the aforementioned tertiles. We performed a stepwise logistic regression analysis to evaluate the predictors for mortality. An additional subgroup analysis was performed by dividing the cases into non-ruptured and ruptured cases.

Results: The preoperative NLR was significantly higher in the non-survivor group than in the survivor group (10.53 ± 7.60 vs. 5.76 ± 6.44, respectively, p = 0.003). The PLR and MPV were similar between the groups (145.35 ± 91.11 vs. 154.20 ± 113.19, p = 0.626, 9.38 ± 1.20 vs. 9.11 ± 1.39, p = 0.267, respectively). The incidence of 1-year mortality was 2.7%, 9.0%, and 14.3% in the first, second, and third NLR tertiles, respectively (p = 0.009). Higher NLR (odds ratio 1.085, 95% confidence interval 1.016-1.159, p = 0.015) and ruptured AAA (odds ratio 2.706, 95% confidence interval 1.097-6.673, p = 0.031) were the independent predictors of 1-year mortality in all patients. Moreover, the preoperative NLR was significantly higher in the ruptured AAA than in the non-ruptured AAA group (11.17 ± 7.90 vs. 4.10 ± 4.75, p < 0.001). In subgroup analysis, preoperative NLR (odds ratio 1.144, 95% confidence interval 1.031-1.271, p = 0.012) and PLR (odds ratio 0.986, 95% confidence interval 16 0.975-0.998, p = 0.017) was an independent predictor for 1-year mortality in ruptured cases.

Conclusions: We demonstrated an independent relationship between the preoperative NLR and 1-year mortality in patients undergoing open AAA repair, besides PLR and MPV. Furthermore, the NLR and PLR had predictive power for 1-year mortality in ruptured cases.