Association of neutrophil-to-lymphocyte ratio with clinical outcomes after percutaneous coronary intervention

Aims Inflammation contributes significantly to coronary artery disease (CAD). The neutrophil-to-lymphocyte ratio (NLR) has emerged as a readily available biomarker reflecting both inflammatory and immune cells' activity, potentially enhancing risk stratification of patients with CAD. This study evaluates the clinical impact of baseline NLR in patients undergoing percutaneous coronary intervention (PCI) for both chronic coronary syndrome and acute coronary syndrome (ACS). Methods and results We conducted a retrospective analysis of patients undergoing PCI at Mount Sinai Hospital between 2012 and 2022. Patients were stratified into NLR quartiles and outcomes were analysed using Cox regression models. The primary endpoint was major adverse cardiovascular events (MACEs) at 1-year follow-up, including all-cause death, myocardial infarction (MI), and stroke. A total of 7287 patients were included in the study. Age, male sex, comorbidities, high-sensitivity C-reactive protein, and complexity of PCI tended to be higher in the highest NLR quartiles. At 1 year, MACE incidence increased across NLR quartiles, from 5.1% (1st quartile) to 9.3% (4th quartile) (P for trend = 0.004). Compared with the 1st quartile, the 4th NLR quartile (NLR > 5.0) was associated with increased adjusted risks of MACE [adjusted hazard ratio (adjHR) 1.52, 95% CI 1.12-2.05], all-cause death (adjHR 1.71, 95% CI 1.10-2.65), MI (adjHR 1.53, 95% CI 1.00-2.35), and bleeding (adjHR 2.01, 95% CI 1.50-2.70). Ischaemic risk associated with high NLR was more pronounced in patients presenting with ACS and chronic kidney disease (CKD). Conclusion Baseline NLR is associated with adverse cardiovascular outcomes in CAD patients undergoing PCI. Assessment of NLR could enhance risk stratification particularly in patients with ACS and CKD.