NEW YORK (Reuters Health) – Three months of dual antiplatelet therapy may be all that’s needed in select patients receiving the second generation zotarolimus-eluting coronary artery stent, a new study confirms.
The optimal length of dual antiplatelet therapy after drug-eluting stent placement remains unclear but the current recommendation is 12 months.
Results of the RESET trial published in 2012 suggested that dual antiplatelet therapy can safely be stopped after three months of placing a zotarolimus-eluting stent in select patients.
Results of the OPTIMIZE Trial published online October 31 in JAMA provide more evidence that three months is adequate.
OPTIMIZE was an open-label, active-controlled randomized noninferiority trial involving 3,119 patients with stable acute coronary syndrome from 33 centers in Brazil.
After percutaneous placement of the Endeavor (Medtronic) zotarolimus-eluting stent, patients received aspirin (100-200 mg daily) and clopidogrel (75 mg daily) for three or 12 months.
At one year, there was no difference between groups in the primary outcome – a composite of all-cause death, myocardial infarction, stroke or major bleeding. This outcome occurred in 93 patients receiving short-term and 90 receiving long-term dual antiplatelet therapy (6.0% vs 5.8%, risk difference 0.17, p=0.002 for noninferiority).
Rates of major adverse cardiac events at one year were also similar with three-month and 12-month antiplatelet therapy (8.3% and 7.4%, respectively; hazard ratio 1.12), according to Dr. Fausto Feres from the Instituto Dante Pazzanese de Cardiologia in São Paulo and colleagues.
Stent thrombosis rates were low and similar in the two groups, the authors report. Up to 90 days, probable or definite stent thrombosis occurred in nine patients (0.6%) in the 3-month group and 11 (0.7%) in the 12-month group. From 91 to 360 days, rates were 0.3% (4 events) in the 3-month group and 0.1% (one event) in the 12-month group.
Stopping dual antiplatelet therapy at three months did not significantly affect the occurrence of either the primary outcome or stent thrombosis, the investigators note in their article.
The findings were similar in several key subgroups including patients with diabetes, history of low-risk acute coronary syndrome, multivessel disease and bifurcation lesions, they say.
Like all studies, OPTIMIZE had its share of limitations, including “relatively low” event rates and a patient population mostly comprised of those with stable coronary artery disease or history of low-risk acute coronary syndrome, the researchers point out.
Also, combining efficacy and safety within a single composite outcome “may be problematic and may mask important differences. However, analysis of MACE did not show any significant differences between durations of dual antiplatelet therapy,” they say.
The authors did not respond to request for comment by press time.
The study was funded by Medtronic Commercial Ltd. Several authors have financial ties to Medtronic, which manufactures the Endeavor zotarolimus-eluting stent used in the study. A complete list of author disclosures is available with the original article.