Millions of chest pain and heart attack sufferers thought they were getting a phenomenal medical advance when tiny coils that ooze medicine were placed in their arteries to keep them from squeezing shut again.

David Reinhart, 41, right, a legal secretary recovering from a blood clot that developed after he received a heart stent, returns to his office after taking a lunchtime walk in Central Park, New York, Thursday Nov. 30, 2006. [AP]

These gizmos, called drug-coated stents, worked so much better than plain old metal ones that 6 million people worldwide received them in the few years they have been available. It was a modern record for any medical device.

Now their long-term safety is in question.

Doctors think these stents may raise the risk of life-threatening blood clots months and even years later unless people stay on Plavix, an anti-clotting drug whose long-term safety in stent patients has not been established.

Thousands of people are being urged to take the $4-a-day drug until more is known.

Thousands of others each day who develop new blockages are being treated by doctors no longer sure of what to do. Many are returning to the old metal stents, and some are fundamentally rethinking when to use stents at all and are considering alternatives like bypass surgery or medications.

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