Association of Lymphocyte-to-Monocyte Ratio With the Mortality in Patients With ST-Elevation Myocardial Infarction Who Underwent Primary Percutaneous Coronary Intervention

We investigated whether the lymphocyte-to-monocyte ratio (LMR) 48 hours after admission is related to 30-day and long-term mortality in patients with ST-elevation myocardial infarction (STEMI) who were treated with primary percutaneous coronary intervention (PCI). We evaluated 318 consecutive patients with STEMI who were undergoing primary PCI. The relationship between the LMR_48h and all-cause mortality (30-day and long-term) was analyzed by categorizing the patients into tertiles (T) according to LMR_48h—T1 (>2.46), T2 (1.67-2.46), and T3 (<1.67). The T3 group exhibited the highest risk of 30-day all-cause mortality (hazard ratio [HR]: 8.093 [1.006-65.074]; P = .049). For long-term mortality, a significantly higher mortality risk was observed in both T2 (HR: 2.005 [1.021-3.939]; P = .043) and T3 groups (HR: 2.374 [1.160-4.857]; P < .001) compared to the T1 group (reference group). In multivariate analysis, these associations remained unaltered even after adjusting for confounders. A low LMR at 48 hours after admission may be independently associated with both 30-day and long-term mortality in patients with STEMI who were treated with primary PCI. This marker may be used for identifying patients with STEMI at high risk.