Late Occlusion of Drug-Eluting Stents Seen After Antiplatelet Therapy Halted

Even a year after placement of drug-eluting coronary stents, in-stent thrombosis may develop if antiplatelet therapy is discontinued, according to a research letter in the October 23rd issue of The Lancet. “For people with a drug-eluting stent, the decision to discontinue aspirin may have consequences,” Dr. Andrew T. L. Ong told Reuters Health.

“We submitted our report to a general medical journal to alert the medical community” to the risk, Dr. Ong said. “You have to weigh the benefit of temporarily discontinuing therapy for elective therapy, i.e., less hemorrhage, versus the risk, which is stent thrombosis.”

A previous meta-analysis of trial data indicated that drug-eluting stents are as safe as bare-metal stents after 6 to 12 months of follow-up (see Reuters Health report August 12, 2004).

Dr. Ong, at Erasmus University in Rotterdam, Netherlands, and colleagues treated four patients, ages 42 to 73 years, who presented with myocardial infarction at 335 to 442 days after undergoing elective implantation of sirolimus- or paclitaxel-eluting stents.

All four had discontinued blood-thinning therapy 4 days to 2 weeks before presentation. In three cases, the drugs had been discontinued to prepare for noncardiac surgery.

In each case, angiography revealed occlusion of the drug-eluting stent. Percutaneous interventions restored vessel patency.

This report is not an argument for returning to bare-metal stents, Dr. Ong noted. “Late thrombosis occurs there, too,” he explained. Because “drug-eluting stents have shown remarkable efficacy at reducing re-stenosis,” they are still preferable to bare-metal stents, he added.

In a related Comment article, Dr. Mark J. Eisenberg advises that some surgical procedures may be appropriately performed without stopping antiplatelet therapy. Otherwise, elective surgery should perhaps be delayed until a year or more after implantation of the drug-eluting stent, or antiplatelet therapy should be discontinued for less than 5 days before the procedure.

He also recommends large-scale registries and post-marketing surveillance studies in order to identify “high-risk characteristics that may predispose to late thrombosis [and] to determine the optimum duration for antiplatelet therapy.”

Until then, “both patients and physicians should be sensitized to the possibility of late stent-thrombosis if antiplatelet therapy is interrupted,” he concludes.