NEW ORLEANS—Researchers said heart valves delivered by catheter matched the success of more invasive open-heart surgery, according to a study of frail, elderly patients. The finding could transform heart care for tens of thousands of patients.

The less-invasive technique, however, carries a higher risk of stroke, prompting doctors to urge caution in adopting the technology should it win approval from the U.S. Food and Drug Administration.

The transcatheter valve is being developed by Edwards Lifesciences Inc., Irvine, Calif., which funded the long-anticipated study called Partner. Study results were presented Sunday at a meeting of the American College of Cardiology.

Currently, U.S. patients needing new valves—about 150,000 a year—have their chests cracked open in hours-long surgeries; others may get no treatment if they are considered too frail for the surgery.

The Edwards device can be threaded up from a leg artery or passed through an incision between the ribs in less-invasive procedures. The valve, made of cow tissue, sits inside a metal cage that is expanded by balloon.