Restenosis is still remained as the most important limitation in clinical practice with coronary stent. Experimental study in a porcine model and clinical study in patients with coronary artery disease were performed to test the efficacy and safety of various anti-platelet agents (Aspirin, Ticlopidine, Cilostazol) to prevent restenosis of coronary stent.

In animal study, Cilostazol 200 mg/day (Group I, n=7) or Ticlopidine 500 mg/day (Group II, n=4) in addition to Aspirin (300 mg/day) was administered to pigs from 3 days before stenting to 4 weeks after stenting. Angiographic and pathologic findings were compared at 4 weeks after stenting. In clinical study, 134 patients underwent coronary stent as Group A (46 patients with 49 lesions:39 M, 7 F:60.8±10.1 year) receiving 300 mg Aspirin and 200 mg Cilostazol, and Group B (88 patients with 92 lesions:63 M, 25 F:60.6±8.8 year) receiving 300 mg Aspirin and 500 mg Ticlopidine between Sep '97 and May '98 at Chonnam University Hospital.

Angiographic degree of stenosis at baseline, immediately after and at 4 weeks after stent was not different between Group I and II. With the histopathologic examination of the stented artery segments 4 weeks after stenting, diameter stenosis was 44.8±25.5% in Group I and 64.2±6.7% in Group II, which was not different (p=0.054). In clinical study, clinical diagnosis and indications for stent were not different between two Groups. Acute stent thrombosis developed in one (1.1%) of Group B and subacute stent thrombosis in three (6.5%) of Group A. Restenosis of the stented coronary artery was observed in 3 (18.8%) in Group A and 10 (37.0%) in Group B (p=NS). Minimal luminal diameter was 2.17±1.49 mm in Group A and 2.05±1.15 mm in Group B (p=NS). No patient in Group A developed side effect, while 4 (4.5%) patients developed side effects including toxic hepatitis in one, gastritis in one patient and thrombocytopenia in two patients.

Combination antiplatelet therapy with Cilostazol and Aspirin is equally effective and more safe in the prevention of coronary stent restenosis, compared with the conventional therapy using Ticlopidine and Aspirin.