CHICAGO (Reuters) - A group representing 3,700 cardiologists on Thursday warned physicians to be careful when recommending drug-eluting stents to treat diseased arteries.

Amid a flurry of controversy over the popular heart implants, the Society for Cardiovascular Angiography and Interventions said it supports continued use, but stressed the importance of careful patient selection, meticulous implantation and consistent use of blood thinners to prevent clots.

Stents, tiny wire mesh tubular devices, are inserted into diseased arteries after the blood vessels have been unclogged. The drug coating on the metal keeps the vessels from reclogging. Drug-eluting stents quickly supplanted the bare metal variety when the drug-eluting versions were launched three years ago.

Recently however, doctors have become concerned about a small, but serious risk of deadly blood clots that can form inside the stent long after they are implanted.

The U.S. Food and Drug Administration is reviewing the matter after an advisory panel debated it last month, concluding that the benefits outweigh the risks when placed in appropriate patients. The panel called for more research.

Dr. Kirk Garratt, clinical director of Interventional Cardiovascular Research at Lenox Hill Hospital in New York, echoed the view of the FDA panel, saying more data were needed to answer important questions, such as what causes the clot formation in the device.

"We don't understand the mechanism of the clots in this instance. Is it the polymer on the stent? That's probably the leading contender, but we don't know," he said.

Garratt is an advisor to Boston Scientific Corp., one of just two manufacturers approved to sell the devices in the United States. Johnson & Johnson is the other company approved to sell drug-eluting stents on the U.S. market.

Abbott Laboratories, Medtronic Inc. and Conor MedSystems, which agreed to be acquired by J&J, sell their own versions overseas, and are poised to launch in the United States over the next couple of years.