One-month duration of dual antiplatelet therapy (DAPT) has widely been adopted after bare-metal stent (BMS) implantation in the real clinical practice. However, it has not been adequately addressed yet whether DAPT for only 1-month could provide sufficient protection from ischemic events beyond 1-month after BMS implantation. We assessed the effects of short DAPT relative to prolonged DAPT on clinical outcomes with the landmark analysis at 2 month after BMS implantation. Among 13,058 consecutive patients enrolled in the CREDO-Kyoto registry cohort-2, this study population consisted of 4905 patients treated with BMS only in whom the information on the status of antiplatelet therapy was available at 2 month after stent implantation [single-antiplatelet therapy (SAPT) group: N = 2575 (acute myocardial infarction (AMI): N = 1257, and non-AMI: N = 1318), and DAPT group: N = 2330 (AMI: N = 1304, and non-AMI: N = 1026)]. Cumulative 3-year incidence of the primary outcome measure (a composite of cardiovascular death, myocardial infarction, stroke, definite stent thrombosis, and GUSTO moderate/severe bleeding) was not significantly different between the SAPT and DAPT groups (9.8 versus 10.6 %, P = 0.34). After adjusting confounders, the risk of SAPT relative to DAPT for the primary outcome measure remained insignificant in the entire cohort (HR 0.97, 95 % CI 0.79-1.19, P = 0.77), and in both AMI and non-AMI strata without any significant interaction between clinical presentation (AMI versus non-AMI) and the effect of SAPT relative to DAPT (P interaction = 0.56). In conclusion, short DAPT <2 month after BMS implantation was as safe as prolonged DAPT ≥2-month in both AMI and non-AMI patients.
Keywords: Bare-metal stent; Coronary disease; Dual antiplatelet therapy.