History of Invasive and Interventional Cardiology - Catheterization of Humans - Modern Controversies in Interventional Cardiology - The Safety of Drug-eluting Stents

The Safety of Drug-eluting Stents

When the results of the first trials of drug-eluting stents were published, there was a general feeling in the interventional cardiology community that these devices would be part of the perfect revascularization regimen for coronary artery disease. With the very low restenosis rates of the RAVEL and SIRIUS trials, interventions were performed on more complex blockages in the coronary arteries, under the assumption that the results in real life would mimic the results in the trials. The antiplatelet regimens that were advised for the drug eluting stents were based on the early trials of these stents. Based on these trials, the antiplatelet regimen was a combination of aspirin and clopidogrel for 3 months when Cypher stents were used, and 9 months when Taxus stents were used, followed by aspirin indefinitely.

Soon, case reports started being published regarding late stent thrombosis. At the 2006 annual meeting of the American College of Cardiology, preliminary results of the BASKET-LATE trial were presented, which showed a slight increase in late thrombosis associated with drug eluting stents over bare metal stents. However, this increase was not statistically significant, and further data would have to be collected. Further data published over the following year had conflicting results, and it was unclear whether stent thrombosis was truly higher when compared to bare metal stents. During this time of uncertainty, many cardiologists started extending the dual antiplatelet regimen of aspirin and clopidogrel in these individuals, as some data suggested that it may prevent late thrombosis.

The FDA held an expert panel in December 2006 to go over the data presented by Cordis and Boston Scientific to determine if drug eluting stents should be considered less safe than bare metal stents. It became evident at the meeting that with all the data published there were varied definitions of late thrombosis and key differences in the types of lesions in different studies, hampering analysis of the data. It was also noted that with the advent of drug eluting stents, interventional cardiologists began performing procedures on more complex lesions, subsequently using the drug eluting stents in "off label" coronary artery lesions, which would otherwise go untreated or for bypass surgery. The FDA advisory board reiterated the ACC guidelines that clopidogrel should be continued for 12 months after drug eluting stent placement in individuals who are at low risk for bleeding.