An implantable medical device, such as a stent or graft, having asperities
on a designated region of its outer surface is disclosed. The asperities
can serve to improve retention of one or more layers of a coating on the
device and to increase the amount of coating that can be carried by the
device. The asperities can be formed by using a stream of pressurized grit
to roughen the surface. The asperities can also be formed by removing
material from the outer surface, for example, by chemical etching with or
without a patterned mask. Alternatively, the asperities can be formed by
adding material to the outer surface, for example, by welding powder
particles to the outer surface or sputtering.
