Stenting has revolutionized the field of interventional cardiology. However, early studies revealed a high incidence of thrombotic occlusion of the stent and significant bleeding complications resulting from the use of intensive anticoagulation after implantation. One of the strategies used to reduce stent thrombosis and hemorrhagic complications has been to decrease the thrombogenicity of the stent surface. For this purpose, a unique heparin surface patented by Carmeda AB (Stockholm, Sweden)--the Carmeda BioActive Surface (CBAS)--has been coated onto Cordis (Johnson & Johnson) stents. Preclinical evaluations of the thromboresistance of heparin-coated stents and clinical studies of heparin-coated stents in a variety of clinical settings are discussed.