Incidence and Outcomes of ST Elevation Myocardial Infarction Caused by Stent Thrombosis in Comparison to De-novo Thrombosis

Introduction: Prior studies suggest that roughly 4 – 6% of ST elevation myocardial infarctions (STEMI) are caused by stent thrombosis. There are limited contemporary data regarding characteristics and outcomes of patients with stent thrombosis presenting with STEMI. We, therefore, aimed to compare clinical and angiographic outcomes between patients presenting with STEMI due stent thrombosis and de novo coronary thrombosis.

Methods: we included 2524 consecutive patients who were hospitalized for STEMI and underwent primary percutaneous coronary intervention (PCI) from 2001 to November 2014. Patients with cardiogenic shock were excluded. We compared the clinical characteristics and outcomes of the 2 groups. The primary end point was one year major adverse cardiac event (MACE) defined as death, nonfatal MI, stroke, or target vessel revascularization.

Results: Stent thrombosis accounted for 4% (n=100) of all STEMIs. A total of 50% were early (≤30 days), and 50% were late stent thrombosis. Stent thrombosis was more often associated with previous MI, previous coronary artery bypass graft surgery, hyperlipidemia and hypertension. TIMI flow rate 0/1 was observed more often at presentation in patients with stent thrombosis (85% vs 62%, p=0.001). Nevertheless, angiographic results were good and similar in both groups (post PCI TIMI flow rate 3 in 95% of patients for both groups). Stenting was preformed less often (75% vs 97%, p<0.001) and GP IIb/IIIa inhibitors administered more often (76% vs 63%, p=0.006) in the stent thrombosis group. One year MACE rate was significantly higher in the stent thrombosis group (27% vs 18.6%, p=0.05), mainly driven by a significantly higher re-MI rate (16.5% vs 5%, p=0.001). Death rate was not significantly higher in the stent thrombosis group (8.1% vs 5.8%, p=0.4).

Conclusions: Although angiographic PCI results were similar, stent thrombosis was associated with worse clinical outcomes in comparison to de-novo STEMI