Glycoprotein IIb/IIIa antagonist FK633 could not prevent neointimal thickening in stent implantation model of canine coronary artery

The platelet glycoprotein (GP) IIb/IIIa receptor antagonist appears to redu ce the need for revascularization after coronary angioplasty. However, sinc e the effect of GP IIb/IIIa receptor antagonist on the in-stent neointimal thickening has not been clarified, we examined it in the canine model. The beagle dogs were assigned to the control (n = 7) or the GP IIb/IIIa recepto r antagonist FK633 group (n = 7), FK633 was administered by subcutaneous os motic pumps (0.2 mg.kg(-1).h(-1)) and an intravenous bolus injection(1 mg/k g) before stenting. A coil stent was implanted in the left circumflex coron ary arteries. The platelet aggregation capability was significantly (<5%) a nd consistently reduced by FK633 except for the mild elevation (10% to 30%) on the next day of stenting. Hearts were excised 3 months after stent impl antation. The area of intima and media and the area stenosis were obtained from the sections of the stented arteries. The area of intima and media and the area stenosis (1.3 +/- 0.2 mm(2), 41.8 +/- 7.5% and 1.3 +/- 0.2 mm(2), 33.9 +/- 6.7% in the FK633 and the control group, respectively) were not d ifferent between the groups. We conclude that, although GP IIb/IIIa antagon ist FK633 prevented the platelet aggregation significantly and consistently , it could not prevent the neointimal thickening after stent implantation i n canine coronary artery.