A clinical risk score for the prediction of very late stent thrombosis in drug eluting stent patients

Aims: Very late stent thrombosis (VLST; >1 year) is an infrequent but potentially serious complication, whose risk factors have not been fully elucidated. This investigation sought to develop a clinically useful risk stratification score for VLST following drug eluting stent (DES) placement. Methods and results: A Cox proportional hazards multivariate model of VLST was developed based on follow-up into a second year of patients enrolled in the ARRIVE registries, utilising readily available baseline clinical and angiographic characteristics. ST predictors between one and two years were identified among 7,459 consecutively enrolled patients who received a TAXUS® Express2™ (Boston Scientific, Natick, MA, USA) DES. Six significant predictors were found: presence of renal disease, prior myocardial infarction, multiple stenting, bifurcation lesions, prior CABG, and smoking at baseline. Each predictor was assigned a score, then summed for a maximum possible score of 10. Stratification into low and high risk groups revealed that VLST developed in 0.5% of 6,759 patients with scores <5, and 2.6% of 700 patients with scores ≥5. Conclusions: We defined a VLST risk score for patients during the second year post DES-placement that provides a useful tool for risk stratification.