LAUSR

Background Elevated neutrophil-to-lymphocyte ratio (NLR) is an indirect marker of inflammation, and is associated with adverse clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI). The aim of this study was to investigate the usefulness of NLR to predict procedural adverse events is patients who underwent primary percutaneous coronary intervention (PCI). Patients and methods Consecutive patients with STEMI who underwent primary PCI were divided into low and high NLR, whereas high was defined as an NLR value above 75° percentile (≥9.45). The occurrence of procedural complications, in-hospital, and 30-day major adverse cardiovascular events and 1-year all-cause mortality were evaluated. Results We included 664 patients with a mean age of 60.5 (±12.1) years and 66.3% were male. In multivariate analysis, NLR remained an independent predictor of in-hospital death [relative risk (RR)=1.03; 95% confidence interval (CI)=1.00–1.08; P=0.04], contrast-induced nephropathy (RR=2.35; 95% CI=1.11–4.71; P=0.02), distal embolization (RR=2.72; 95% CI=1.55–4.75; P<0.001), and no-reflow (RR=2.31; 95% CI=2.31–4.68; P=0.01). The area under the curve for distal embolization was 0.67, 0.64 for no-reflow and 0.62 for procedural complications. A low value of NLR had an excellent negative predictive value of 97.8, 96.9, and 92.1 for distal embolization, no-reflow, and procedural complications, respectively. Conclusion High NLR is an independent predictor of distal embolization, no-reflow, and procedural complications in patients with STEMI who underwent primary PCI. A low NLR value has an excellent negative predictive value for these procedural outcomes. NLR may be a useful and inexpensive tool that may be used at bedside.