Prognostic value of neutrophil to lymphocyte ratio in patients presenting with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention.

Atherosclerosis is an inflammatory process, and inflammatory biomarkers have been identified as useful predictors of clinical outcomes. The prognostic value of leukocyte count in patients with ST-segment elevation myocardial infarctions who undergo primary percutaneous coronary intervention is not clearly defined. In 325 patients with STEMIs treated with primary percutaneous coronary intervention, total and differential leukocyte counts, once at admission and 24 hours thereafter, were measured. The neutrophil/lymphocyte ratio (NLR) was calculated as the ratio of neutrophil count to lymphocyte count. The primary end point was all-cause death. Twenty-five patients (7.7%) died during follow-up (median 1,092 days, interquartile range 632 to 1,464). The total leukocyte count decreased (from 11,853 ± 3,946/μl to 11,245 ± 3,979/μl, p = 0.004) from baseline to 24 hours after admission. Patients who died had higher neutrophil counts (9,887 ± 5,417/μl vs 8,399 ± 3,639/μl, p = 0.061), lower lymphocyte counts (1,566 ± 786/μl vs 1,899 ± 770/μl, p = 0.039), and higher NLRs (8.58 ± 7.41 vs 5.51 ± 4.20, p = 0.001) at 24 hours after admission. Baseline leukocyte profile was not associated with outcomes. The best cut-off value of 24-hour NLR to predict mortality was 5.44 (area under the curve 0.72, 95% confidence interval [CI] 0.52 to 0.82). In multivariate analysis, a 24-hour NLR ≥5.44 was an independent predictor of mortality (hazard ratio 3.12, 95% CI 1.14 to 8.55), along with chronic kidney disease (hazard ratio 4.23, 95% CI 1.62 to 11.1) and the left ventricular ejection fraction (hazard ratio 0.94 for a 3% increase, 95% CI 0.76 to 0.93). In conclusion, NLR at 24 hours after admission can be used for risk stratification in patients with STEMIs who undergo primary PCI. Patients with STEMIs with 24-hour NLRs ≥5.44 are at increased risk for mortality and should receive more intensive treatment.