Double antiplatelet therapy after drug-eluting stent implantation: risk associated with discontinuation within the first year.

OBJECTIVES The goal of this study was to assess the risk associated with double antiplatelet therapy (DAT) discontinuation, and specifically, temporary discontinuation, during the first year after drug-eluting stent (DES) implantation. BACKGROUND Doubts remain about the risk of temporary DAT discontinuation within 1 year after DES implantation. METHODS A total of 1,622 consecutive patients undergoing DES implantation at 29 hospitals were followed up at 3, 6, 9, and 12 months to record the 1-year antiplatelet therapy discontinuation (ATD) rate, the number of days without DAT, and the rate of 1-year major cardiac events. Cox regression was used to analyze the association between ATD considered as a time-dependent covariate and 1-year cardiac events. RESULTS One hundred seventy-two (10.6%) patients interrupted at least 1 antiplatelet drug during the first year after DES implantation, although only 1 during the first month. Most (n=111, 64.5%) interrupted DAT temporarily (median: 7 days; range: 5 to 8.5): 79 clopidogrel (31 temporarily), 38 aspirin (27 temporarily), and 55 both drugs (53 temporarily). Discontinuation was followed by acute coronary syndrome in 7 (4.1%; 95% confidence interval [CI]: 1.7 to 8.2), a similar rate of major cardiac events to that in patients without ATD (n=80; 5.5%; 95% CI: 4.4 to 6.8; p=0.23). ATD was not independently associated with 1-year major cardiac events (hazard ratio: 1.32 [95% CI: 0.56 to 3.12]). CONCLUSIONS ATD within the first year and beyond the first month after DES is not exceptional, is usually temporary, and does not appear to have a large impact on risk.