Incidence, implications, and predictors of stent thrombosis in acute myocardial infarction

Stent thrombosis (ST) remains a catastrophic problem in patients undergoing percutaneous coronary intervention (PCI). However, a paucity of data exist regarding the incidence, implications, and predictors of ST in patients with acute myocardial infarction (AMI). We consecutively enrolled patients with AMI in the CardiOvascular Risk and idEntificAtion of potential high-risk population in AMI registry who underwent PCI from January 2004 to December 2009 and analyzed definite or probable ST according to Academic Research Consortium definitions. The median follow-up duration was 41.9 months. Definite or probable ST occurred in 136 patients (3.7%), including 44 with early ST (1.0%), 38 with late ST (0.9%), and 54 with very late ST (2.0%). The annual incidence of very late ST ranged from 0.5% to 0.6%. The all-cause mortality rate after ST was 29%, which was higher than that for patients without ST (17%; p <0.001). The independent predictors of ST were no-reflow phenomenon (hazard ratio [HR] 1.96, 95% confidence interval [CI] 1.28 to 3.03), decreased left ventricular ejection fraction (HR 1.70, 95% CI 1.21 to 2.40), anemia (HR 1.54, 95% CI 1.09 to 2.18), and a mean stent diameter <3.0 mm (HR 1.53, 95% CI 1.04 to 2.27). ST is not uncommon in patients with AMI and continues to occur beyond 1 year after PCI, irrespective of the stent type or clinical presentation. Patients with ST are associated with higher mortality than patients without ST. No reflow, decreased left ventricular ejection fraction, anemia, and a mean stent diameter <3.0 mm are independent predictors of ST.