Following endarterectomy, platelets adhere and aggregate on the endarterectomized surface and release platelet-derived growth factor which induces smooth muscle cell migration and proliferation which may result in restenosis. Many patients had been treated with aspirin and dipyridamole, but not in a controlled trial. The Recurrent Carotid Stenosis Study established whether antiplatelet therapy was beneficial in the prevention of recurrent carotid artery stenosis.