Larry Bordeaux, 65, has been on blood thinners since 2010, after he started developing deadly clots following an operation. He credits the drugs with saving his life. If he stops taking them for several days — which he must sometimes do before certain medical procedures — clots develop quickly. Still, Bordeaux, of Havelock, North Carolina, knows that being on blood thinners is a double-edged sword: They put him at a heightened risk of serious, uncontrolled bleeding. Since he started taking them,