RESET Study Suggests Shorter Duration Dual Antiplatelet Therapy With ZES

Dual antiplatelet therapy (DAT) following drug-eluting stent (DES) placement is the focus of two separate studies published on Sept. 19 in the Journal of the American College of Cardiology.

The first study, known as RESET, explores the safety and efficacy of short-duration DAT following implantation of the Endeavor zotarolimus-eluting stent (E-ZES), compared to 12-month DAT following other DES implantation. The results found that three-month DAT after E-ZES implantation was safe and noninferior to the standard therapy in terms of the primary composite endpoint (cardiovascular death, myocardial infarction, stent thrombosis, target\vessel revascularization or bleeding) at one year. Specifically, the primary endpoint occurred in 40 (4.7 percent) patients assigned to E-ZES_3-month DAPT compared with 41 (4.7 percent) patients assigned to the standard therapy (difference: 0.0 percent; 95 percent confidence interval [CI]: _2.5 to 2.5; p _ 0.84; p _ 0.001 for noninferiority).

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While the study authors note several limitations to the study – including the sample size of 2,117 patients, study design and the lack of high-risk patients – they suggest that three-month  DAT following E-ZES implantation "could be safe and beneficial for selected patients with coronary artery disease who may need to stop [DAT] early after DES implantation." However, they caution that "generalized application of these results to the entire population demands careful attention." In particular, they note that careful assessment of risks for stent thrombosis and bleeding should be weighed at the individual patient level.

The second study assesses the risk associated with (DAT) discontinuation, specifically temporary discontinuation, during the first year after DES implantation. The study followed a total of 1,622 patients who underwent DES implantation at 29 hospitals at three, six, nine and 12 months.  Of those, 172 (10.6 percent) patients interrupted at least one antiplatelet drug during the first year, although most interruptions were temporary, and all but one were after the first month of DES implantation. Broken down by drug, 79 patients discontinued clopidogrel (31 temporarily); 38 discontinued aspirin (27 temporarily); and 55 discontinued both drugs (53 temporarily). Discontinuation was followed by acute coronary syndrome in seven patients (4.1 percent; 95% confidence interval [CI]: 1.7 to 8.2), a similar rate of major cardiac events to that in patients without discontinuation in the first year (n _ 80; 5.5 percent; 95 percent CI: 4.4 to 6.8; p _ 0.23).

According to the study authors, the results suggest that discontinuation of antiplatelet therapy in the first year and beyond the first month after DES is not exceptional, usually temporary, and does not appear to have a large impact on risk. "Although further knowledge about individual risk is desirable, our results suggest that discontinuation for a few days (median: seven days) of DAT after the first month of DES implantation may be reasonably safe in terms of major cardiac events," they said.

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