In a sub-analysis of the DAPT (Dual Antiplatelet Therapy) study, researchers found significant reductions in stent thrombosis and myocardial infarction (MI) in patients treated with everolimus-eluting stents (EES) and continued thienopyridine beyond 1 year compared to aspirin alone.
Researchers evaluated the risks and benefits of thienopyridine plus aspirin treatment for 30 vs 12 months in a large subset of patients. Of the 11 648 randomized patients, 9961 received a drug-eluting stent (DES) with the following stent types: everolimus (47.2%), paclitaxel (26.8%), zotarolimus (12.7%), sirolimus (11.2%), and more than 1 type of DES (2.1%).
Stent thrombosis and MI were both reduced with continued thienopyridine therapy compared with placebo (interaction P=.76; P=.11, respectively), as was the increase in bleeding and mortality (interaction P=.46; P=.17, respectively). These outcomes were consistent across all DES types after adjustment for differences in patient characteristics and thienopyridine type. However, in the degree of risk reduction in major adverse cardiovascular and cerebrovascular events (MACCE) was varied, depending on the stent (interaction P=.048).
Compared with placebo, continued thienopyridine significantly reduced rates of stent thrombosis among EES-treated patients (0.3% vs 0.7%; hazard ratio [HR]: 0.38; 95% confidence interval [CI]: 0.15-0.97; P=.04). MI rates were also significantly reduced (2.1% vs 3.2%; HR: 0.63; CI: 0.44-0.91; P=.01), but not MACCE (4.3% vs 4.5%; HR: 0.89; 95% CI: 0.67-1.19; P=.42).
All-cause mortality was 2.2% in the continued thienopyridine group vs 1.1% with placebo, 12 to 30 months after enrollment (HR: 1.80; CI: 1.11-2.91; P=.02). There was no difference in cardiovascular death (1.0% continued thienopyridine vs 0.8% placebo; HR: 1.42; 95% CI: 0.75-2.69; P=.28), but there was an observable difference in noncardiovascular death (1.2% continued thienopyridine vs 0.4% placebo; HR: 3.46; 95% CI: 1.49-8.04; P=.002).
The most common cause of noncardiovascular death was cancer, which included some deaths associated with bleeding (3 of 18 patients in the thienopyridine group vs 0 of 4 in the placebo group). Overall, moderate or severe bleeding was higher in the continued thienopyridine group (2.5% vs 1.3%; HR: 1.79; 95% CI: 1.15-2.80; P=.01).
“As the hazard of very late stent-related events (>1 year) may different between DES types, the potential benefit (or harm) associated with continued thienopyridine therapy beyond 1 year may be different as well,” researchers wrote. “Additional research is needed to further individualize therapy to optimize patient selection for continued thienopyridine therapy.”
Hermiller JB, Krucoff MW, Kereiakes DJ, et al. Benefits and risks of extended dual antiplatelet therapy after everolimus-eluting stents. JACC Cardiovasc Interv. 2016;9(2):138-147. doi: 10.1016/j.jcin.2015.10.001.