One of most important mechanisms of coronary stent restenosis is neointimal hyperplasia. Although the process of neointima formation is not fully understood, a special role has been advocated for adherent platelets. Previous studies have shown a clear benefit with combined antiplatelet therapy such as aspirin plus ticlopidine in reducing the rate of thrombotic occlusions of stented vessels. The purpose of this study was to evaluate the effects of duration of antiplatelet regimens on coronary stent restenosis.

After successful placement of coronary artery stents in 222 patients, we performed follow-up coronary angiograms in 99 patients (42.3%). Forty-six patients were randomly assi-gned to receive aspirin and ticlopidine for four weeks (Group I: 54±9 years: M 38, F 8) and 48 patients for 6 months (Group II: 58±8 years: M 38, F 10).

There were no significant differences in clinical and procedural variables or coronary lesion characteristics before and after stenting. At 6 months after stenting, minimal luminal diameter was 2.16±0.93mm in Group I and 2.04±1.07mm in Group II (p-0.57). Late lumen loss was 0.80±1.07mm in Group I and 0.92±1.11mm (p-0.58) in Group II. The stent restenosis rate of Group I at 28.3% and that of Group II at 29.2% were not statistically significant between the two groups (p-0.92).

The therapeutic duration of combined antiplatelet regimen with aspirin and ticlopidine after coronary stent does not affect stent restenosis rate.