Retrospective Evaluation of the Pre- and Postoperative Neutrophil-Lymphocyte Ratio as a Predictor of Mortality in Patients Who Underwent Coronary Artery Bypass Grafting

Background: We aimed to investigate the neutrophil-lymphocyte ratio (NLR) as a predictor of mortality in patients, who had undergone on-pump and off-pump coronary artery bypass grafting (CABG). Methods: This retrospective study comprised of 457 patients, who underwent CABG (323 on-pump and 134 off pump) between January 2014 and October 2019. Preoperative, postoperative (PO) 1st hour, PO 1st day, and PO 5th day neutrophil-lymphocyte ratios were calculated. The patients were compared, according to demographic, laboratory, and clinical data. A receiver operating characteristics curve was applied to estimate a cut-off value of NLR for mortality. Results: The on-pump group was older (P = 0.001), had a lower Euroscore II (P = 0.036), had a higher graft number (P < 0.001), intensive care unit stay (P = 0.001), and all PO NLRs, except preoperative NLR. There were 14 (3.06%) patients with mortality. Overall (N = 457), PO 1st hour (P = 0.001), PO 1st day (P < 0.001), and PO 5th day (P = 0.016) NLRs were considerably higher in patients with mortality. While none of the NLRs revealed significant difference in the off-pump group, PO 1st hour (P = 0.004) PO 1st day (P 0.001), and PO 5th day (P = 0.007) NLRs were higher in patients with mortality in the on-pump group. The increase in odds ratio of PO NLR was higher in patients with mortality in the overall group of PO 1st day and in the on-pump group of PO 1st hour and PO 1st day. The best combination of sensitivity and specificity was reached at a cut-off value of 6.4 for PO 1st hour NLR and 31.8 for PO 1st day NLR. Conclusions: As in indicator of inflammatory state, NLR readily can be used as a predictor of mortality. Regardless of the CABG technique used, postoperative 1st hour and postoperative 1st day NLR 6.4 and 31.8, respectively, are highly related to mortality.

Automated summary

The study identified neutrophil-lymphocyte ratio (NLR) as a predictor of mortality in patients undergoing coronary artery bypass grafting (CABG). Postoperative 1st hour and 1st day NLR levels were significantly higher in patients who died.