Prevalence and outcomes of early versus late stent thrombosis presenting as ST-segment elevation myocardial infarction

OBJECTIVES: Previous reports showed inconsistencies in the outcomes and prognosis of stent thrombosis (ST) when stratified according to the timing of its occurrence. We evaluated the incidence and possible prognostic implications of early and late ST presenting as ST-segment elevation myocardial infarction (STEMI) in a large cohort of consecutive patients undergoing a primary percutaneous coronary intervention. MATERIALS AND METHODS: We retrospectively studied 1722 STEMI patients treated by primary percutaneous coronary intervention. The presence of ST was determined using the Academic Research Consortium definitions. Patients were evaluated for the time of ST (early, late) and for in-hospital outcomes as well as long-term mortality. RESULTS: A total of 83/1722 (4.8%) patients showed definite ST, 35 (42%) of whom had early ST and 48 (58%) had late ST. Patients with early ST had more adverse events during hospitalization as well as higher 30-day mortality compared with patients with late or no ST (11 vs. 0 vs. 2%, P<0.001). In a multivariate logistic regression model, early ST was an independent predictor of 30-day mortality (odds ratio 6.6, 95% confidence interval 1.1-38, P=0.033). No significant difference was observed in long-term mortality between patients presenting with early, late ST, or no ST. CONCLUSION: Early ST manifested as STEMI is associated independently with a higher 30-day mortality rate in comparison with STEMI because of late ST or de-novo coronary thrombosis.