A plaque tack device for treating atherosclerotic occlusive disease is formed as a thin, annular band made of thin, flexible wire formed in a mesh structure having a plurality of barbs on its outer periphery. It has a width that is small relative to its diameter, to minimize the amount of foreign structure placed in the blood vessel. One or more tacks may be applied in positions along a plaque accumulation site as needed to stabilize the site and/or hold pieces of plaque out of the way of blood flow. The barbs of the tack may be pressed into the plaque and/or blood vessel walls by balloon expansion. Related methods of deployment and delivery devices are provided for insertion of the plaque tack in a compressed state into the blood vessel and expanding it back to its annular shape for holding plaque against the blood vessel walls.