Impact of neutrophil-to-lymphocyte ratio on clinical outcomes in patients with acute or chronic coronary syndrome undergoing percutaneous coronary intervention

Abstract Background Neutrophil-to-lymphocyte ratio (NLR) has recently emerged as an inflammatory biomarker associated with atherosclerosis and cardiovascular events. However, its role in patients with coronary artery disease (CAD) undergoing percutaneous coronary intervention (PCI) remains unclear. Purpose We aimed to evaluate the clinical impact of baseline NLR in patients undergoing PCI for acute coronary syndrome (ACS) and chronic coronary syndrome (CCS). Methods We retrospectively evaluated all consecutive patients undergoing PCI between 2012-2022 in a large tertiary US hospital. We excluded patients for whom NLR was not available and those who were deemed to have active hematological or infective diseases, including patients presenting with extremely low or high lymphocyte and neutrophil counts or with hs-CRP above 10 mg/L. Quartiles of NLR were derived in the overall population and patients were stratified according to clinical presentation. Within each group, we estimated the risk of 12-month adverse events using the lowest NLR quartile as reference. The primary endpoint was major adverse cardiovascular events (MACE), defined as the composite of all-cause death, myocardial infarction (MI), or stroke. Secondary endpoints were MACE individual components and any periprocedural or post-discharge clinically relevant bleeding. Results A total of 7,201 patients were included in the analysis; of these 3,975 (55.2%) had ACS and 3,226 (44.8%) CCS. Patients in the 4th quartile (NLR > 5.0) were more frequently male, older, and presented more often with chronic kidney disease and complex coronary artery disease. Smoking, diabetes and history of CAD, as well as triglycerides, LDL, non-HDL and total cholesterol levels were lower in the 4th NLR quartile. In patients presenting with CCS, the risk of MACE, all-cause death, MI was similar across NLR quartiles, while the risk of bleeding increased stepwise (Figure 1). In patients presenting with ACS, the 4th NLR quartile had the highest adjusted risk of MACE (HRadj 1.82, 95% CI 1.25-2.67; P=0.002), all cause death (HRadj 2.56, 95% CI 1.41-4.66; P<0.001), and bleeding (HRadj 1.82 95% CI 1.25-2.63, P<0.001) at 1 year, as compared to the lowest quartile (Table 1). Conclusions Among patients undergoing PCI, elevated NLR is strongly associated with risk of MACE and all-cause mortality in patients presenting with ACS but not in those with CCS. Conversely, the risk of bleeding was augmented with higher NLR in both ACS and CCS patients undergoing PCI. In this setting, NLR may inform risk stratification at the time of PCI.