a metal endoprosthesis or precursor tubing thereof and exposing the powder to a heat source to melt the powder and liberate hydrogen gas thereby forming a porous coating on the surface of the endoprosthesis or precursor tubing thereof application_number US 85112707 A description fig1 depicts an endoprosthesis in the form of a stent 20 stent 20 could have the form of a tubular member defined by a plurality of bands 22 and a plurality of connectors 24 that extend between and connect adjacent bands during use bands 22 could be expanded from an initial small diameter to a larger diameter to contact stent 20 against a wall of a vessel thereby maintaining the patency of the vessel connectors 24 could provide stent 20 with flexibility and conformability that allow the stent to adapt to the contours of the vessel stent 20 could be of a desired shape and size e g coronary stents aortic stents peripheral vascular stents gastrointestinal stents urology stents and neurology stents depending on the application stent 20 could have a diameter of between for example 1 mm to 46 mm in certain embodiments a coronary stent could have an expanded diameter of from 2 mm to 6 mm in some embodiments a peripheral stent could have an expanded diameter of from 5 mm to 24 mm in certain embodiments a gastrointestinal and or urology.