Washington, D.C. ? Drug-coated stents that prop open the arteries of about 3 million people in the U.S. don’t increase the risk of heart attack or death when used as labeled but may put patients at risk for blood clots, health advisers said Thursday.

While the panel of experts broadly dismissed the more serious risks, they split on characterizing the degree of the increased clotting risk in comparison with older, bare-metal stents. They agreed only that more study of the newer devices is needed.

The panel also said any safety concerns fail to outweigh the benefits of the stents – tiny mesh tubes used like scaffolding to keep blood free-flowing through the arteries. Drugs that coat the stents elute, or dissolve, into the bloodstream to prevent reclogging of arteries.

The mixed verdict came at the outset of a two-day meeting of the Food and Drug Administration advisers, convened to discuss possible clotting and associated risks of the drug-coated stents. The panel’s findings Thursday apply only to the minority of patients for whom the FDA-approved labeling says use of the devices is appropriate.