We used traditional frequentist statistical and Bayesian approaches to address the following questions: Q1) What is the minimum duration of
DAPT required after DES implantation? Q2) What is the clinical benefit of prolonging
DAPT up to 18 to 48 months? Q3) What is the clinical effect of
DAPT in stable patients who are >1 year past an MI?
RESULTS: We reviewed evidence from 11 randomized controlled trials (RCTs) that enrolled 33 051 patients who received predominantly newer-generation DES to answer: A1) Use of
DAPT for 12 months, as compared with use for 3 to 6 months, resulted in no significant differences in incidence of death (odds ratio [OR]: 1.17; 95% confidence interval [CI]: 0.85 to 1.63), major
hemorrhage (OR: 1.65; 95% CI: 0.97 to 2.82), MI (OR: 0.87; 95% CI: 0.65 to 1.18), or
stent thrombosis (OR: 0.87; 95% CI: 0.49 to 1.55). Bayesian models confirmed the primary analysis. A2) Use of
DAPT for 18 to 48 months, compared with use for 6 to 12 months, was associated with no difference in incidence of all-cause death (OR: 1.14; 95% CI: 0.92 to 1.42) but was associated with increased major
hemorrhage (OR: 1.58; 95% CI: 1.20 to 2.09), decreased MI (OR: 0.67; 95% CI: 0.47 to 0.95), and decreased
stent thrombosis (OR: 0.45; 95% CI: 0.24 to 0.74). A risk-benefit analysis found 3 fewer
stent thromboses (95% CI: 2 to 5) and 6 fewer MIs (95% CI: 2 to 11) but 5 more major bleeds (95% CI: 3 to 9) per 1000 patients treated with prolonged
DAPT per year. Post hoc analyses provided weak evidence of increased mortality with prolonged
DAPT. We reviewed evidence from 1 RCT of 21 162 patients and a post hoc analysis of 1 RCT of 15 603 patients to answer: A3): Use of
DAPT >1 year after MI reduced the composite risk of cardiovascular death, MI, or
stroke (hazard ratio: 0.84; 95% CI: 0.74 to 0.95) but increased major
bleeding (hazard ratio: 2.32; 95% CI: 1.68 to 3.21). A meta-analysis and a post hoc analysis of an RCT in patients with stable
cardiovascular disease produced similar findings.
CONCLUSIONS: The primary analysis provides moderately strong evidence that prolonged
DAPT after implantation of newer-generation DES entails a tradeoff between reductions in
stent thrombosis and MI and increases in major
hemorrhage. Secondary analyses provide weak evidence of increased mortality with prolonged
DAPT after DES implantation. In patients whose coronary thrombotic risk was defined by a prior MI rather than by DES implantation, the primary analysis provides moderately strong evidence of reduced cardiovascular events at the expense of increased
bleeding.