FDA to probe Safety of Medicated Stents

Drug-coated stents have provided relief to millions of chest pain and heart attack sufferers around the world but now doctors think these stents may raise the risk of life-threatening blood clots months and even years later unless people stay on Plavix, placing their long-term safety in doubts.

A drug-coated or medicated stent is a very small, expandable mesh-like metal cylinder, coated with medicine that decreases scar formation on the stent, and fits over an uninflated angioplasty balloon. These stents are used to open up a coronary (heart) blood vessel that is narrowed or blocked by plaque build-up (atherosclerosis), and to maintain that opening by permanently placing a metal stent within the heart artery. These metal stents help restore normal blood flow to the heart muscle.

Now the drug-coated stents therapy is facing questions from heart experts who are doubtful about the device’s long-term safety. They say it is possible that if a patient does not stay on Plavix, an anti-clotting drug, his chances of developing dangerous blood clots are significantly raised.

In a Swiss study, it was found that patients with medicated stents had double the risk of heart problems after stopping Plavix than those with older, bare-metal stents, and that the medicated stents carry a higher risk of potentially fatal blood clots than plain metal stents.

But, the problem is that nobody knows how safe the long-term taking of Plavix as the $4-a-day anti-clotting drug’s long-term safety in stent patients has not been yet established.

But doctors are still worried these stents may raise the risk of potential life-threatening blood clots months and even years later unless their patients remain on Plavix. At the same time, they are ambiguous what therapy should be used on them who are developing new blockages.

Most of them, 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 use just drugs. However, thousands of people are being urged to take the Plavix until more is known.

Some doctors say the raised risk is not significant as only about five clots are found in every 1,000 drug-coated stent patients, and are concerned overreaction to the risk could sabotage patients' long term options.

A Food and Drug Administration panel will meet to discuss the safety of heart stents on Thursday and Friday. The panel will seek to recommend a standard definition for late stent thrombosis, and settle many other issues, like when the stents should be used, what causes the clots, and whether the condition is common to all medicated stent brands.

This is not the first time the medicated stents are facing criticism, even three years ago the US FDA issued a warning after receiving more than 290 reports of blood clots in patients using Cypher drug coated devices by Johnson & Johnson's Cordis Corp. with more than 60 deaths associated with them.

Dr. Robert Califf of Duke University, who worked on one study to be presented to the FDA, said, "It's such a huge public health issue with so many people involved."

Of approximately sixty lakh patients worldwide, estimated 4 million Americans are walking around with the drug stents implanted inside their bodies, while about 1.5 lakh patients using them in India since June 2002. As per the estimates of the Interventional Council of India, 60% of the 65,000 stents implanted in the country last year were drug-coated.

The market of medicated stents is estimated at more than $5 billion a year. These drug coated stents cost around three times as much as old, bare-metal devices.