NEW YORK (Reuters Health) – Triple antiplatelet therapy is more effective than dual therapy at reducing ischemic events after implantation of a drug-eluting stent (DES), according to an observational study in the American Heart Journal for February.
The oral antiplatelet agent cilostazol, approved by the U.S. Food and Drug Administration for treatment of intermittent claudication, adds to the effects of aspirin and clopidogrel against platelet activation, the authors note. In earlier studies, the drug reduced rates of restenosis and revascularization in patients with DES.
In the current analysis, co-author Dr. Seung-Jung Park and colleagues at the University of Ulsan College of Medicine in Seoul, South Korea, compared the long-term effectiveness and safety of a triple-drug regiment and a dual-drug regimen after successful implantation of a sirolimus- or paclitaxel-eluting stent.
Out of 3099 patients treated at their institution, 1443 had received triple therapy: aspirin 200 mg/day, clopidogrel (300-mg loading dose, then 75 mg/day), and cilostazol (200-mg loading dose, then 100 mg twice daily). The other 1646 patients received only aspirin and clopidogrel.
Aspirin was administered indefinitely, clopidogrel for at least 6 months, and cilostazol for at least 4 weeks. Follow-up lasted for 12 months.
In the triple therapy group, 5 patients had myocardial infarctions (MI), 2 had stent thrombosis, and 21 died. In the double-therapy group, 15 had MIs, 12 had stent thromboses, and 26 died.
After adjustment,12-month mortality did not differ between the groups. However, the triple-antiplatelet therapy was associated with significantly lower 12-month risks of MI (hazard ratio 0.233, p = 0.0097) and stent thrombosis (HR 0.136, p = 0.0036). Incidence curves for both stent thrombosis and MI diverged and reached statistical significance at 2 months, after which the curves were parallel.
Rates of major bleeding were similar in the two groups.
The investigators theorize that in addition to its antiplatelet effect, cilostazol may have several favorable effects on the vascular bed, such as inhibition of atheroma plaque formation, atheroma regression, vasodilatation and favorable change of lipid profile.
They conclude,
