Someday, if inventor Richard Hines has his way, the human heart will be repaired with tiny tubes of pure gold. Hines invented a technique to spin 24-karat gold into something even more valuable: coronary stents, the devices used by doctors to prop open blocked arteries and prevent bypass surgery. Gold, Hines says, is flexible, tissue-friendly, and easily visible on X-rays. A golden stent may seem an extreme symbol of the increasingly costly world of cardiovascular devices. But Hines's vision is hardly unusual among the dozens of new ideas competing for a niche in the vast global market for stents.