Federal health officials have approved a first-of-a-kind artificial heart valve that can be implanted without major surgery, offering a new treatment option for patients who are too old or frail for the chest-opening procedure currently used. The Food and Drug Administration said Wednesday it approved Edwards Lifesciences' Sapien heart valve, which can be threaded into place through a major artery that runs from the leg to the heart. Cardiologists say the new approach will help old, sickly patients who cannot undergo open heart surgery, which has been used to replace valves for decades.