Patent ID: 7985252

Claim:
An endoprosthesis comprising a plurality of struts defining a flow passage, at least one strut comprising: (a) a body comprising a bioerodible material having a thickness, and (b) a coating overlying the body, the coating comprising a plurality of regions that allow physiological fluids to contact a plurality of corresponding areas of the underlying body when the endoprosthesis is implanted in a physiological environment, the plurality of regions being sized and arranged so that the contacted areas of the body erode substantially through the body in the thickness direction while the coating remains on the body when the endoprosthesis is implanted in the physiological environment, wherein a rate of erosion of the body in the thickness direction multiplied by the thickness of the body is less than a rate of erosion of the body along an interface between the body and the coating multiplied by the distance between adjacent regions thereby producing undercut regions.