New Orleans ? Tiny clogged arteries in the heart that have long bedeviled cardiologists’ attempts at repair can now be kept flowing smoothly with new drug-coated stents that have already revolutionized treatment of larger vessels.

Research released Sunday suggests these tiny wire coils should solve one of the major problems of treating people with chest pain caused by buildups in the arteries that feed their hearts.

While fat arteries are relatively easy to fix, about two-thirds of patients undergoing angioplasty suffer from blockages in very skinny ones — under 2 millimeters in diameter. Typically doctors squeeze these arteries open with a balloon and install a stent, but about half the time, they clog again.

In the past year, many doctors have switched to a new kind of stent that exudes a drug that prevents the artery from filling in. Results from early studies suggested they may work for small arteries as well as big, but a team from Italy was the first to test the idea directly.

Their data, released in New Orleans at a meeting of the American College of Cardiology, showed a dramatic improvement with the Cypher stent in small arteries, reducing the failure to just 10 percent.

“This is very important, because these are the vessels that give us the most problems,” commented Dr. George Mensah, cardiology chief at the Centers for Disease Control and Prevention.