In a packed hearing room at the Food and Drug Administration last week, a panel of cardiac experts met to consider what was obviously an important question: Has one of the most popular treatments for heart disease in fact been killing some of the patients it is meant to help?

Three years ago, doctors began using a new device called a drug-coated stent — a tiny metal tube — to keep blocked heart arteries open. It cost a lot more than an uncoated stent, but because it seemed to be far more effective, it quickly began to dominate the stent market. Last year, Johnson & Johnson and Boston Scientific together sold more than one million drug-coated stents. They have become a primary treatment for this country’s No. 1 cause of death.

In recent months, though, researchers found a disturbing pattern. People with a drug-coated stent seemed unusually vulnerable to blood clots in later years. The new stents solved one problem, but they may have created another. So the F.D.A. summoned its cardiology advisers to review the evidence.

After listening to testimony, they concluded that for healthier patients with simple forms of heart disease, the benefits of drug-coated stents appeared to outweigh the risks. The picture was less clear for people with diabetes, multiple blocked arteries or other complications. In the end, the panel concluded that doctors and patients needed to be aware of the risks and that researchers should continue collecting data. The entire affair — from the invention of the new stent to the willingness to reconsider it — was in many ways an impressive display of American medicine.