Inflammatory and insulin resistance indicators for predicting in-stent restenosis in patients with chronic coronary syndrome undergoing percutaneous coronary intervention

Background The C-Reactive protein-triglyceride glucose index(CTI), a reliable surrogate indicator of inflammatory and insulin resistance, is independently associated with coronary artery disease of various clinical manifestations. This study aimed to investigate the prognostic value of the CTI index in predicting in-stent restenosis (ISR) in chronic coronary syndrome (CCS) patients undergoing percutaneous coronary intervention (PCI). Methods A total of 2147 participants were enrolled and divided into groups according to the tertiles of the CTI index. The primary endpoint was the incidence of ISR. Log-rank tests and Kaplan-Meier methods were performed to explore differences in event rates between CTI tertiles and plot time-to-event curves. The associations between the CTI index and the primary endpoint were assessed by multivariable Cox proportional hazards regression analysis with restricted cubic splines (RCS). The predictive performance of the models was evaluated using receiver operating characteristic (ROC) curves, with the area under curve (AUC) metric quantifying the model’s discriminative ability. The value of the CTI was defined as the Ln (fasting triglycerides (mg/dL)×fasting plasma glucose (mg/dL)/2) + 0.412 × ln [CRP (mg/L)]. Results Over a median follow-up of 60 months, 449 (20.91%) patients had experienced at least one primary endpoint event. The follow-up incidence of the primary endpoint increased with the CTI index tertiles. After adjusting for potential confounders, the CTI index was independently associated with the primary endpoint in CCS patients (HR, 1.17; 95% CI 1.02-1.34; P=0.025). Additionally, the highest tertile of the CTI group was correlated with a 1.35-fold risk of the primary endpoint compared with the lowest tertile of the CTI group (HR, 1.35; 95% CI 1.06-1.72; P=0.016). Furthermore, a linear and dose-response relationship was observed between the CTI index and the primary endpoint (non-linear P=0.119, P overall=0.019). CTI index, age, gender, BMI, diabetes, hypertension, previous PCI, previous MI, Lp(a), HbA1c, presence of multivessel CAD, presence of lesion length≥20 mm, number of stents, and stent length can be used as independent variables to construct a clinical prediction model. The ROC analysis demonstrated that this multivariate prediction model had moderate predictive accuracy for the primary endpoint, with area-under-the-curve estimates of 0.68 (95%CI 0.65-0.71) at 3 years and 0.70 (95%CI 0.67-0.73) at 5 years. Conclusions An increased CTI index was associated with elevated risk for ISR. Our study suggested that the CTI index could be a potent predictor in evaluating the prognosis of CCS patients undergoing PCI.