a medical device comprising a coating thereon comprising a biocompatible polymer and heparin is provided herein . heparin is coupled with the biocompatible polymer via a spacer having a grouping that renders a binding site of the heparin molecule accessible by a binding protein . the medical device can be implanted in a human being for the treatment of a disease such as atherosclerosis , thrombosis , restenosis , hemorrhage , vascular dissection or perforation , vascular aneurysm , vulnerable plaque , chronic total occlusion , claudication , anastomotic proliferation for vein and artificial grafts , bile duct obstruction , ureter obstruction , tumor obstruction , or combinations thereof .