Although the pre-procedural neutrophil to lymphocyte ratio (N/L) has been associated with adverse outcomes among patients with coronary artery disease, its role during the acute phase of ST-segment elevation myocardial infarction (STEMI) has not been fully investigated. This study sought to investigate the association of the pre-procedural N/L ratio within-hospital and long-term outcomes among STEMI patients undergoing primary percutaneous coronary intervention (PCI).

Inflammation plays a role in the initiation and progression of the atherosclerotic process. Due to a growing recognition of its role, recent studies have focused on inflammatory markers and their association with outcomes in patients with ST-segment elevation myocardial infarction (STEMI). Recently, our single center study demonstrated that preprocedural neutrophil/lymphocyte (N/L) ratio is an independent predictor of impaired coronary flow after primary percutaneous coronary intervention (PCI) and of in-hospital major advanced cardiac events (MACE) in patients with STEMI.Several previous studies also evaluated the role of N/L ratio in long-term outcomes among patients with STEMI; however, they evaluated the association between long-term mortality and in-hospital N/L ratio, they were single-center studies and they evaluated a relatively small study population.

In the present multicenter experience, the investigators aimed to investigate the association of the preprocedural N/L ratio with the in-hospital and long-term outcomes in patients with STEMI undergoing primary PCI.

Inclusion Criteria:

ST elevated myocardial infarction

Exclusion Criteria:

Treatment with fibrinolytic drugs in the previous 24 hours Active infection Previously documented history of a systemic inflammatory process Known malignancy End-stage liver disease Renal failure

STEMI patients who were admitted within 6 hours from symptom onset and who underwent primary PCI were prospectively included in this study