Neutrophil to Lymphocyte Ratio Predicts Perioperative Mortality Following Open Elective Repair of Abdominal Aortic Aneurysms

Objectives: This study assesses the predictive value of neutrophil to lymphocyte ratio (NLR) in relation to 30-day and overall mortality following open abdominal aortic aneurysm (AAA) repairs. In addition, it assess assesses any correlation between NLR and age, size of the AAA and gender. Methods: Patients undergoing elective or urgent open repair of their AAA by a single surgeon during a 10-year period were included. A pre-operative NLR of >5 was regarded as abnormal. Results: 350 consecutive patients underwent AAA repair. 52 had an NLR>5. 30-day mortality rate was 12/52 (23%) in the NLR>5 group and 20/298 (6.7%) in the NLR<5 group (p = 0.0007). All deaths in the NLR>5 group were due to myocardial infarction. The median NLR was higher in those that died within 30 days at 4.2 [IQR: 2.6-7.5] versus 2.8 [IQR: 2.1-3.8] (p = 0.0001). Overall mortality at 10 years, in the NLR>5 group - 26/52 (50%) was significantly greater than that of the NLR<5 group - 102/298 (34.2%) (p = 0.043). Median NLR of those dying during follow-up was significantly higher in those with a baseline NLR>5 at 3.2 (IQR 2.5-4.6) versus 2.6 (IQR: 2.0-3.6) in those surviving (p = 0.00004). No difference was found between NLR and age, aneurysm size or gender. Conclusion: Pre-operative NLR>5 appears to be a significant predictor of both 30-day mortality and long-term outcome in elective and urgent open AAA surgery. It is plausible the NLR is identifying a group with sub-clinical cardiovascular disease at risk of peri-operative myocardial infarction.