Neutrophil/Lymphocyte Ratio as a Predictor of LongTerm Survival After Open Abdominal Aortic Aneurysm Repair
Natour AK, Hares K, Shepard A, and Kabbani L. Neutrophil/Lymphocyte Ratio as a Predictor of LongTerm Survival After Open Abdominal Aortic Aneurysm Repair. J Vasc Surg 2022; 75(6):E148-E149.
J Vasc Surg
Objectives: The neutrophil/lymphocyte ratio (NLR) is an easily measured laboratory marker that reflects systemic inflammation. Recent studies have suggested that cardiovascular patients’ preoperative NLR could be a prognostic marker of poorer outcomes. The NLR in abdominal aortic aneurysm (AAA) patients has been poorly studied.
Methods: We performed a retrospective study of all patients who underwent elective AAA repair at our institution between 1995 and 2019. Patients with a complete white blood cell differential within 30 days before AAA repair were included in the study. The NLR was computed by dividing the absolute neutrophil count by the absolute lymphocytic count. A receiver operating characteristic curve and log-rank tests were used to determine the optimal NLR cutoff. Univariate and multivariate logistic regression analyses were performed to assess the predictors of mortality. A Kaplan-Meier survival analysis was performed.
Results: Among 1139 patients identified, 277 met the inclusion criteria. Of the 277 patients, 71 (25%) had undergone endovascular aneurysm repair (EVAR) and 206 (75%) had undergone open repair (OR). The median NLR was 3.5 for EVAR and 2.7 for OR (P = .054). The 30-day mortality was 1.4% (n = 1) and 4.4% (n = 9) for EVAR and OR, respectively. The NLR was not a predictor of postoperative mortality. The NLR was also not associated with long-term survival in the EVAR group. An NLR of <3 was associated with long-term survival in the OR group (P < .001). In the OR group, 91 patients (44%) had had an NLR of ≥3.0 (OR group 1), and 115 had had an NLR <3 (OR group 2). OR group 1 had an older mean age (71 vs 68 years; P < .001) and a longer mean length of stay (12 vs 9 days; P < .001) compared with OR group 2. Kaplan-Meier estimates of mortality were significantly greater for OR group 1 (P < .001; Fig). The mean NLR for those who had died was significantly greater than that for those who survived (6.0 ± 7.0 vs 3.6 ± 4.0; P < .001). On multivariate analysis, an NLR of ≥3 (hazard ratio [HR], 2.7; 95% confidence interval [CI], 1.3-5.7; P < .01) was predictive of poor long-term survival. Male gender (HR, 0.5; 95% CI, 0.3-0.96; P = .036) and statin use (HR, 0.46; 95% CI, 0.2-0.9; P = .017) were predictive of improved survival.
Conclusions: An increased NLR was an independent predictor of long-term mortality for AAA patients undergoing OR but not EVAR. Patients with a high NLR might have shorter survival; thus, caution should be advised in offering these patients OR for AAAs. Risk stratification of AAA patients undergoing OR deserves further research. FigKaplan-Meier curves comparing survival time between the two neutrophil/lymphocyte (NLR) open repair (OR) groups.