Objectives To evaluate the efficacy of cilostazol, a new synthetic inhibitor of phosphodiesterase, in preventing stent thrombosis after successful implantation.

Design Preliminary prospective study.

Setting A single coronary care unit in Japan.

Patients Elective, bailout, or primary stents were implanted in 85 consecutive patients with 93 lesions. Primary stent implantation was performed in 18 patients with acute myocardial infarction. Patients received 200 mg cilostazol and 243 mg aspirin after stenting.

Main outcome measures Stent thrombosis, major and minor complications, and side effects were assessed in the six months after stenting.

Results Gianturco-Roubin stents were implanted in 37 lesions, Wiktor stents in 55, and Palmaz-Schatz stents in 27. Multiple stents were used in 26 lesions. There was no mortality, stent thrombosis related Q wave myocardial infarction, emergency bypass surgery, repeat intervention, or vascular complications in the six months of follow up. Acute or subacute closure did not occur after stenting. There were no serious side effects such as leucopenia and/or abnormal liver function for three months. Cilostazol was withdrawn in one patient because of skin rash. Patients who underwent primary stenting had no clinical events, such as acute or subacute thrombosis, or side effects.

Conclusions Cilostazol is an effective antiplatelet agent with minimum side effects after elective, bailout, or primary stent implantation.