Background: Late angiographic stent thrombosis(LAST) may be a potential limitation of DES implantation. Our concerns are that sudden cardiac death(SCD) out of hospital may be related with LAST. The aim of this study was to describe the incidence and clinical characteristics of LAST and SCD out of hospital. Methods: In total 2390 patients (M:F=1506:884, mean age 66짹10 yrs) underwent coronary intervention with DES from March 2003 to April 2005, either sirolimus-eluting stent (SES) (1699 patients,1840 lesion, 2158 stents) or paclitaxel-eluting stent (PES) (750 patients,821 lesion,895 stents), prospective observational cohort study was done. LAST was defined as angiographic proven stent thrombosis associated more than 30 days with DES. Patients who could not be followed were interviewed by telephone to identify the SCD out of hospital. Results: 1.There were three angiographic confirmed LAST events ( all were SES, at 3,14,14 months after procedure) and SCD out of hospital was five ( four with SES at 3.4,9 month and unknown period, one with PES at 9 month). Two patients with LAST were presented with non-STEMI on aspirin monotherapy and dual therapy with aspirin and clopidogrel in conventional dose respectively. The other patient was presented as fatal STEMI on aspirin monotherapy (Table). 2. Two SCD were occurred during complete cessation of antiplatelet therapy and other two were on aspirin monotherapy. Conclusions: Incidence of angiographic confirmed LAST and SCD after DES implantation was at least 0.12% and 0.21 %. Clinical presentation with LAST event was fatal. Single or even dual antiplatelet therapy was not safe to prevent late stent thrombosis. LAST should be considered as the cause of SCD after DES implantation, especially in discontinuation of antiplatelet therapy