Thrombosis Associated with Coronary Drug-Eluting Stents

In December 2006, FDA convened an advisory panel to evaluate what is known about the risk of thrombosis in patients with drug-eluting stents. These stents, the Cypher and Taxus, were approved by FDA because they can reduce the incidence of vessel restenosis when compared with bare metal stents. But information collected after they were marketed showed that both of them are associated with an increased risk of thrombosis after one year compared with bare metal stents.

This presents a benefit vs. risk situation for the healthcare provider and the patient. The device can reduce restenosis rates and thereby avoid subsequent surgery, but it can also increase the risk of serious clotting. The risk is small (from less than 1 percent to about 5 percent) but when a thrombus occurs it can lead to sudden death or acute MI.

When the panel looked at the risk of thrombosis in patients with these stents, they found that this risk varies depending on how the device is used. When the stents were used in clinically stable patients with lesions less than 28-30 mm (i.e., the criteria specified in the product labeling), the benefits of the device in reducing restenosis could outweigh the thrombosis risk. But when the stents were used "off label" (i.e., in patients with more complex lesions or various co-existing conditions) the risk of thrombosis was higher.

The panel emphasized the importance of giving these patients antiplatelet medication after the surgery to reduce the risk of clotting. The panel also noted that current guidelines suggest giving these patients the antiplatelet therapy for 12 months after surgery, provided the patient is not at high risk of bleeding.

In addition, the panel recommended that larger, longer studies be done to determine how long the risk of thrombosis persists after surgery and how long antiplatelet therapy needs to be continued. Until these studies are completed, there are a few patient management issues that clinicians might want to consider.

First, there is the finding that the risk of thrombosis is higher when the device is used "off-label". Second, clinicians should understand importance of keeping patients on antiplatelet therapy for a long enough time, and educating them not to discontinue this therapy without medical consultation. Patients who cannot comply with long-term antiplatelet therapy may not be good candidates for a drug eluting stent. The same holds true for patients who have planned surgical procedures that would require discontinuing this therapy.

Category:

News & Politics

Tags:

• Coronary
• Drug-Eluting
• Stents
• Thrombosis
• Cypher
• Taxus
• Patient
• Safety
• Restenosis
• Antiplatelet
• Therapy