Stents are small mesh tubes that prop open narrowed or blocked body passages to restore flow. Coronary stents (bare-metal, drug-eluting, bioresorbable) treat heart artery disease via angioplasty BMS heal quickly but risk restenosis; DES release antiproliferatives cutting re-narrowing to <10%; BVS dissolve after 2-3 years. Vascular stents address peripheral/carotid arteries in PAD/stroke prevention. Ureteral stents bypass kidney stone obstructions with pigtail ends. Biliary stents relieve liver duct blockages from tumors/gallstones. Esophageal/intestinal stents palliate cancer obstructions. Deployment uses catheter balloons or self-expansion under X-ray guidance; dual antiplatelets prevent clots.