Some additional analyses followed that further combed through the data from trials that had compared drug-eluting and bare-metal stents, but, by and large, these metaanalyses have used the same set of studies. For example, a metaanalysis presented by researchers from the Cleveland Clinic last November at the AHA's scientific sessions that focused on paclitaxel-eluting stents added just one additional study (TAXUS VI) to the seven studies of paclitaxel-eluting stents first reviewed by Dr. Eisenberg and his associates. The new analysis, which included a total of nearly 4,000 patients, again showed no statistically significant difference in the stent thrombosis rate between the paclitaxel and bare-metal stents.
“The real limitation is that the studies all had built-in treatment with aspirin and clopidogrel. What is unclear is whether there is any increased risk for stent thrombosis, compared with bare-metal stents in patients who are not treated with aspirin and clopidogrel. This has not been addressed,” Dr. Bhatt said.
“It would be very serious if we had to avoid surgery [to avoid stopping aspirin] forever in patients with drug-eluting stents,” said David J. Cohen, M.D., associate director of interventional cardiology at Beth Israel Deaconess Medical Center in Boston.
In light of the concern about late thrombosis, Dr. Eisenberg advises physicians to take three actions: First, consider the potential consequences of implanting a drug-eluting stent in a specific patient, and perhaps use a bare-metal stent instead if the patient is known to need surgery later or if the patient's compliance with chronic antiplatelet therapy is questionable. Second, use registries and postmarketing studies to better define the risk, identify clinical factors that boost a patient's risk, and determine the optimal duration of antiplatelet therapy. Third, develop new strategies to deal with potential interruptions of antiplatelet therapy, including the possibility of continuing antiplatelet therapy during surgery, and delaying surgery for more than a year after a patient receives a drug-eluting stent.