Platelet deposition at angioplasty sites and its relation to restenosis in human iliac and femoropopliteal arteries.

The amount and time course of platelet accumulation at angioplasty sites and influence of these platelets on restenosis after percutaneous transluminal angioplasty (PTA) in peripheral arteries were determined in 92 patients, who received either a high or low dose of aspirin. Platelet deposition was quantitated by means of dual-radiotracer scintigraphy and calculation of a platelet accumulation index (PAI). The PAI was higher (P less than .05) 4-6 hours after PTA compared with that on subsequent days. There was a trend toward greater platelet accumulation in vessels with extensive dissection. Platelet accumulation at the PTA site occurred with both doses of aspirin, with no differences between the two dosage groups. Twenty-one of 67 patients who underwent PTA in the femoropopliteal segment developed restenosis during a median follow-up of 14 months. The median PAI at 4-6 and 22-24 hours after PTA was significantly less in these 21 patients than in the 46 without restenosis. The data suggest that use of antiplatelet agents to prevent platelet deposition after PTA may not be useful for prevention of restenosis.