Duke researchers reveal their findings on drug-eluting stents and share the latest recommendations.

Heart patients who have received drug-eluting stents to hold open an artery and who stop taking the drug clopidogrel (known by the brand name Plavix) to reduce blood clotting may face more than double the risk of death or heart attack than patients who continue on the drug, according to an analysis by Duke Clinical Research Institute investigators.

Patients who receive drug-eluting stents may need to continue taking clopidogrel for much longer than previously thought, the researchers said. Duke cardiologists Robert M. Califf, MD, and David F. Kong, MD, two of the co-authors of the recent stent study, address some questions about stents and about their new research findings.

Q: What is a stent?

A: Stents are thin metal mesh tubes that prop open the arteries that supply blood to the heart. Physicians often implant stents after unblocking a coronary artery with a tiny balloon in a procedure known as angioplasty (angio=blood vessel, plasty=fix). Stents reduce the risk of recurring blockages in coronary arteries after the artery has been opened.

The first stents, known as bare metal stents, were not coated with medicine. Unfortunately, the artery sometimes forms a scar inside the stent, and this scar can block the stent. As a result, patients sometimes need to have another angioplasty.

Newer stents have been coated with drugs designed to prevent the build-up of scar tissue inside the stent. These devices are called drug-coated or drug-eluting stents, and nine out of 10 stents placed in the U.S. today are this kind. Drug-eluting stents reduce the need for a repeat procedure from one in five (for bare metal stents) to one in 12 (for drug-eluting stents).

Q: Why are doctors concerned about drug-eluting stents?

A: Recent reports have shown that drug-eluting or drug-coated stents may be associated with the development of blood clots that could lead to heart attacks or death. The risk of a blood clot inside a stent is eight in 1,000. For comparison, your risk of dying in an automobile accident is six in 1,000.

Q: Is there a way to stop such clots from developing?

A: To stop clots from forming within a drug-coated stent, doctors have their patients take aspirin, if they are able to, along with Plavix for at least 12 months, as recommended by the American Heart Association, the American College of Cardiology, the Society for Cardiovascular Angiography and Interventions, the American College of Surgeons, and the American Dental Association.

The most common side effects of Plavix are stomach pain, gastrointestinal discomfort, headaches, dizziness, and bleeding. Patients taking Plavix may be asked by their doctors to stop taking the drug if they are going to have an invasive procedure or surgery that could lead to bleeding.

Q: Are there any problems associated with stopping Plavix?

A: Recent reports suggest that patients who stop taking Plavix three to six months after placement of a drug coated stent have higher rates of heart attacks and death than those who continue to take it. Because of these recent findings, we recommend that unless there is a reason not to take Plavix it should be continued until better information is available.

No clinical trials have been done yet to understand the effects of long-term Plavix use, so these recommendations are temporary until further long-term studies are done to clarify these issues.

It is important to recognize that these trials could take five years to complete, so in the meantime you should have a discussion with your doctor to make a good decision based on the information we currently have available.

Robert M. Califf, MD
Vice Chancellor for Clinical Research
Director, Duke Translational Medicine Institute

David F. Kong, MD
Assistant Professor of Medicine Duke
Clinical Research Institute

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