In 2013, the FDA approved an implantable device to treat leaky heart valves. Among its inventors was Mehmet Oz, the former television personality and former U.S. Senate candidate widely known as “Dr. Oz.” In online videos, Oz has called the process that brought the MitraClip device to market an example of American medicine firing “on all cylinders,” and he has compared it to “landing a man on the moon.” MitraClip was designed to spare patients from open-heart surgery by snaking hardware into the heart through a major vein. Its manufacturer, Abbott, said it offered new hope for people severely …