Short and Optimal Duration of Dual Antiplatelet Therapy Study (STOPDAPT)

• Major cardiovascular and bleeding events [ Time Frame: 1-year ]
  Composite of cardiovascular death, myocardial infarction, stroke (ischemic and hemorrhagic), stent thrombosis (definite stent thrombosis not resulting in myocardial infarction), and major bleeding (TIMI Major/Minor) Cardiovascular death, myocardial infarction and stent thrombosis are defined according to the definition in the Academic Research Consortium (ARC). Stroke is defined as ischemic or hemorrhagic stroke with symptoms lasting > 24 hour. Major bleeding is defined according to the definition in the Thrombosis in Myocardial Infarction (TIMI).
  
  

• Cardiovascular death/MI/stroke/definite ST [ Time Frame: 1-year ]
  Composite of cardiovascular death, myocardial infarction, stroke, and definite stent thrombosis
  
  
• Major bleeding (TIMI Major/Minor) [ Time Frame: 1-year ]
  Major bleeding (TIMI Major/Minor)
  
  
• Death/MI [ Time Frame: 1-year ]
  Composite of all-cause death and myocardial infarction
  
  
• All-cause death [ Time Frame: 1-year ]
  All-cause death
  
  
• Cardiovascular death/MI [ Time Frame: 1-year ]
  Composite of cardiovascular death and myocardial infarction
  
  
• Cardiovascular death [ Time Frame: 1-year ]
  Cardiovascular death
  
  
• MI [ Time Frame: 1-year ]
  Myocardial infarction
  
  
• Stroke [ Time Frame: 1-year ]
  Both ischemic and hemorrhagic stroke excluding transient ischemic attack
  
  
• Stent Thrombosis [ Time Frame: 1-year ]
  Stent thrombosis according to Academic Research Consortium classification
  
  
• Target Lesion Failure [ Time Frame: 1-year ]
  Composite of cardiovascular death, myocardial infarction due to target vessel, and target lesion revascularization
  
  
• Target Vessel Failure [ Time Frame: 1-year ]
  Composite of cardiovascular death, myocardial infarction, and target vessel revascularization
  
  
• Major Adverse Cardiac Events [ Time Frame: 1-year ]
  Composite of cardiovascular death, myocardial infarction, and clinically-driven target lesion revascularization
  
  
• Target Lesion Revascularization [ Time Frame: 1-year ]
  Target lesion revascularization
  
  
• Clinically-driven Target Lesion Revascularization [ Time Frame: 1-year ]
  Clinically-driven Target Lesion Revascularization
  
  
• Non Target Lesion Revascularization [ Time Frame: 1-year ]
  Revascularization for non-target vessel or target vessel but target lesion
  
  
• CABG [ Time Frame: 1-year ]
  Coronary artery bypass graft
  
  
• Target Vessel Revascularization [ Time Frame: 1-year ]
  Target vessel revascularization
  
  
• Any bleeding [ Time Frame: 1-year ]
  Any bleeding complications
  
  

"Thienopyridine antiplatelet agents have markedly inhibited incidence of stent thrombosis, when they were combined with aspirin for 1 month after implantation of bare-metal stent (BMS). On the other hand, combination of aspirin with thienopyridine (dual antiplatelet therapy: DAPT) for more than 1 year after drug-eluting stent (DES) implantation is frequently used to prevent very late stent thrombosis in the current clinical practice. In the RESET study, which was carried out in clinical practice in Japan, DAPT was performed for at least 1 year in 90% of the patients. However, there has been no report showing that long-term thienopyridine treatment for at least 1 year reduces incidence of serious cardiovascular events, and large-scale observational studies or small-scale randomized comparative studies have demonstrated that thienopyridine treatment for 6 months or for at least 12 months does not reduce incidence of serious cardiovascular events. These results suggest that the optimal duration of DAPT after DES implantation may be shorter than 6 months.

With respect to Everolimus-eluting stent (EES), which is the most widely used DES in Japan, it has been associated with significantly lower incidence of early or late stent thrombosis compared with the first-generation DES and with BMS in large-scale observational study and randomized comparative studies and their meta-analyses.

Considering that long-term DAPT obviously increases hemorrhagic complications compared to Aspirin monotherapy, it is desirable to reduce the duration of DAPT as far as possible, if long-term DAPT is not effective in inhibiting the incidence of serious cardiovascular events. Moreover, long-term DAPT enormously increases medical expenses. In this study, we planned an exploratory multicenter study to evaluate incidences of cardiovascular events and bleeding events at 12 months after stent implantation using an EES (XIENCE Prime™), which is associated with low risk of stent thrombosis, when thienopyridine therapy is discontinued at 3 months after surgery.