Early Stent Thrombosis in Patients Undergoing Primary Coronary Stenting for Acute Myocardial Infarction: Incidence, a Simple Risk Score, and Prognosis

Background: One of the major concerns remaining in the treatment with stenting of patients with acute myocardial infarction (AMI) is the occurrence of stent thrombosis (ST). The aim of the current study is to investigate the incidence, predictors, and long-term outcomes of early ST after primary coronary stenting for AMI in a large population. Methods: We reviewed 1960 consecutive patients (mean age 56 ± 11.6 years, 1658 males) treated with primary coronary stenting for AMI between 2003 and 2008. All clinical, angiographic, and follow-up data were retrospectively collected. Early ST was defined as thrombosis that occurred in the first 30 days after primary coronary stenting. Results: Early ST was observed in 89 (4.5%) patients. Five variables, selected from the multivariate analysis, were weighted proportionally to their respective odds ratio (OR) for early ST (premature clopidogrel therapy discontinuation [10 points], stent diameter ≤3 mm [5 points], current smoker [4 points], diabetes mellitus [DM; 3 points], and age >65 years [2 points]). Three strata of risks were defined (low risk, score 0-4; intermediate risk, score 5-12; and high risk, score 13-24) and had a strong association with early ST and long-term cardiovascular mortality. Long-term cardiovascular mortality was 5-fold more in patients with early ST than that without ST (24.1% vs 4.7%, respectively, P < .001). Conclusions: Early ST after primary coronary stenting in AMI is strongly related with increased long-term cardiovascular mortality. Premature clopidogrel therapy discontinuation is the most powerful predictor of early ST.