The role of inflammation and coronary artery lesion severity in patients undergoing percutaneous coronary intervention: a retrospective cohort study

Inflammation contributes to the pathogenesis and adverse outcomes of coronary heart disease (CHD). However, the role of coronary lesion severity in inflammation-associated prognosis in patients following percutaneous coronary intervention (PCI) remains unclear. This study aimed to investigate the interrelationships among systemic inflammation, coronary lesion complexity, and post-PCI prognosis. A total of 1232 PCI patients from the Third People’s Hospital of Chengdu between July 2018 and December 2020 were included. Multivariate Cox regression models were used to evaluate the associations of the baseline neutrophil–lymphocyte ratio (NLR, a marker of systemic inflammation) and the Synergy between PCI with Taxus and Cardiac Surgery (SYNTAX) score with major adverse cardiac events (MACEs). Mediation analysis was used to assess the role of the SYNTAX score in these associations. During a median follow-up period of 29.60 months, 239 patients experienced MACEs. After adjustment for multiple confounders, the NLR and SYNTAX score were significantly and positively associated with the risk of MACEs in patients after PCI. Mediation analysis revealed that the SYNTAX score partially mediated the association between the NLR and MACEs, which accounted for 24.92% of the total effect even after multivariable adjustment. Combining the NLR and SYNTAX score improved the predictive performance for MACEs compared with either marker alone, especially within the first year (AUC = 0.841). Coronary lesion severity partially mediates the impact of systemic inflammation on adverse prognosis in PCI patients. These findings suggest that dynamic NLR monitoring and early anti-inflammatory interventions may benefit patients with a high inflammatory burden after PCI.