The Effects of Anti-Platelet Agents in Preventing Coronary Stent Restenosis

ABSTRACT

BACKGROUND: 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. METHODS: 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 lesions39 M, 7 F60.8+/-10.1 year) receiving 300 mg Aspirin and 200 mg Cilostazol, and Group B (88 patients with 92 lesions63 M, 25 F60.6+/-8.8 year) receiving 300 mg Aspirin and 500 mg Ticlopidine between Sep '97 and May '98 at Chonnam University Hospital. RESULTS: 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. CONCLUSION: 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.