Association of serum platelet-to-lymphocyte ratio levels with the risk of stent thrombosis and long-term prognosis in patients undergoing percutaneous coronary intervention with and without type 2 diabetes mellitus: a large-scale prospective cohort study

Background The platelet-to-lymphocyte ratio (PLR) is a promising inflammatory biomarker contributing to the development of atherosclerosis and type 2 diabetes mellitus (T2DM). Therefore, this study aims to document the value of PLR in predicting adverse events in patients undergoing percutaneous coronary intervention (PCI) with and without T2DM. Methods This study consecutively enrolled 8831 patients who received PCI, and we divided them into 4 groups according to the PLR level and glycemic metabolic statuses (PLR-low/high with non-T2DM, PLR-low/high with T2DM). The endpoints were major adverse cardiovascular and cerebrovascular events (MACCE) and stent thrombosis. Multivariate COX regression analysis was used to determine the association. Results During the 2.4-year follow-up, a total of 663 (7.5%) MACCE and 75 (0.85%) stent thrombosis were recorded. Results showed that patients with high PLR levels presented a significantly higher risk of MACCE (HR: 1.26, 95%CI: 1.07 to 1.47, P = 0.005) and stent thrombosis (HR: 2.29, 95%CI, 1.39 to 3.79, P = 0.001) when compared with the PLR-low group. When focused on patients with T2DM, the PLR-high group showed a significantly higher risk of MACCE (HR: 1.53, 95%CI: 1.17 to 2.00, P = 0.002) and stent thrombosis (HR: 3.79, 95%CI, 1.62 to 8.86, P = 0.002). However, these associations were not significant in patients without T2DM. Conclusions For the first time, PLR is documented as a great predictor for the poor prognosis and high incidence of stent thrombosis in patients with CAD, especially in those with T2DM. CLINICAL PERSPECTIVE What Is New? In patients undergoing percutaneous coronary intervention (PCI), high serum platelet-to-lymphocyte ratio (PLR) is associated with poor prognosis and a high risk of stent thrombosis. When focusing on patients with different glycemia statuses, we found that the predictive value of PLR for poor prognosis and high risk of stent thrombosis was significant in patients with type 2 diabetes mellitus (T2DM), but not in patients without T2DM. Among patients with different PLR levels and glycemia statuses, those combined with both high PLR levels and T2DM showed the highest risk of poor prognosis and stent thrombosis. In stent thrombosis events, very late stent thrombosis is the most common type in patients with high PLR. What Are the Clinical Implications? Patients undergoing PCI with high PLR levels should be monitored closely. Residual inflammation should be focused among patients with coronary heart disease after revascularization to improve the long-term prognosis.