A RANDOMIZED TRIAL OF ASPIRIN VERSUS CILOSTAZOL THERAPY AFTER SUCCESSFUL CORONARY STENT IMPLANTATION

Percutaneous transluminal coronary angioplasty (PTCA) is widely used t o treat patients with ischemic heart disease, but the procedure involv es a number of problems, including acute coronary occlusion and resten osis. Although stents have proved useful for preventing post-PTCA rest enosis, especially elastic recoil during the acute phase, no method ha s yet been established to prevent restenosis caused by vascular smooth muscle cell proliferation in the late phase. Cilostazol selectively i nhibits the 3'5'-cyclic-nucleotide phosphodiesterase (PDE) III (cyclic guanosine monophosphate-inhibited PDE) of the cyclic adenosine monoph osphate PDE family; it also has antithrombotic and vasodilating effect s, as well as an inhibitory effect on vascular smooth muscle cell prol iferation through PDE III inhibition. From November 1995 to March 1997 , the usefulness of cilostazol versus aspirin in preventing subacute t hrombosis and restenosis was studied in 70 patients (55 men and 15 wom en; 82 total lesions) who had undergone successful elective Palmaz-Sch atz stent implantation. Patients were randomly allocated to receive as pirin 81 mg/d (40 patients with 45 lesions) or cilostazol 200 mg/d (30 patients with 37 lesions) alone. There was no difference in patient o r angiographic characteristics between these groups. No subacute throm bosis, acute complications tie, death, emergent coronary artery bypass grafting, or hemorrhagic complications), or drug side effects were fo und in the cilostazol group. The minimal lumen diameter (mean +/- SD) at follow-up was 1.89 +/- 1.08 mm in the aspirin group (41 lesions, 5. 63 +/- 1.74 months after stent implantation) and 2.34 +/- 0.74 mm in t he cilostazol group (35 lesions, 5.14 +/- 1.91 months after stent impl antation), revealing statistically significant dilatation in the cilos tazol group. The restenosis rate was 26.8% in the aspirin group, compa red with 8.6% in the cilostazol group; this difference was statistical ly significant. Administration of cilostazol alone after the implantat ion of intracoronary Palmaz-Schatz stents was useful for the preventio n of subacute thrombosis and restenosis.