Value of neutrophil to lymphocyte ratio as a predictor of mortality in patients undergoing aortic valve replacement.

Background: Neutrophil to lymphocyte ratio (NLR) has been studied as a measure of inflammation and as a prognosticating factor in various medical conditions including neoplastic, inflammatory and cardiovascular. The prognostic role of NLR in predicting mortality in patients with aortic stenosis undergoing surgical aortic valve replacement (AVR) has not been studied. The aim of our study is to explore the utility of NLR as a predictor of both, short and long-term mortality, in patients undergoing surgical AVR.

Methods: Consecutive patients with aortic stenosis admitted for AVR to our institution were evaluated for study inclusion. Of the 335 patients admitted from January 2007 to September 2011, 234 met study inclusion criteria. Patients were divided into two groups depending on their initial preoperative NLR level with a cutoff value of 3. Three-year vital status was accessed with electronic medical records and Social Security Death Index. Survival analysis, stratified by NLR, was used to evaluate the predictive value of preoperative NLR levels.

Results: Patients with NLR ≥3, when compared to those with NLR <3, had a significantly higher short-term (9.40% 0, P=0.0006), 6-month (19.54% 0.95%, P<0.0001), and 3-year mortality (27.35% 3.78%, P<0.0001). After adjustment for baseline characteristics, co-morbidities, symptomatology, echocardiographic findings, and blood tests, NLR level remained a significant independent predictor of 3-year mortality; Hazard ratios (HRs) increased by a factor of 1.18 (1.05-1.33, P=0.0068) and patients with a NLR ≥3 had 4.77 fold increase in 3-year mortality (1.48-15.32, P=0.0090).

Conclusions: NLR is an independent predictor of short-term and long-term mortality in patients with aortic stenosis undergoing AVR surgery, especially those with NLR ≥3. We strongly suggest the use of NLR as a tool to risk stratify patients with aortic stenosis undergoing AVR surgery.