An expandable cage is expanded within a narrowed region of a blood vessel. The expandable cage has openings therein so that plaque protrudes through the openings when the cage is expanded. A material removing element passes within the cage to remove the plaque extending into the openings. The openings are preferably formed by integrally formed elements which provide a smooth internal surface. The material removing element passes along the smooth internal surface when removing the plaque. A collection bag is coupled to the material removing element to capture the material which has been removed.