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.