November 10, 2011

November 9, 2011 (San Francisco, California) — Results from a large case-control registry of first-generation drug-eluting stents (DES) suggests that patients are not in the clear from stent thrombosis after one year or even after many years post stent implantation. Patients taking dual antiplatelet therapy with aspirin and clopidogrel (Plavix, Bristol-Myers Squibb/Sanofi-Aventis), were not protected either, report investigators, with approximately one-third of stent-thrombosis events occurring in patients taking aspirin and clopidogrel.

Dr Ron Waksman

"This is a study with the first-generation drug-eluting stents, so we can't say anything about the next generation," lead investigator Dr Ron Waksman (Washington Hospital, Washington, DC) told heartwire . "The results show that you can't really declare yourself free of stent thrombosis after one year, or three years, or more. There is an increased risk in some patients out to at least seven years."

The results of the study, an analysis from the Drug-Eluting Stent Event Registry of Thrombosis (DESERT), were presented this week at TCT 2011. The study, with patients from more than 40 clinical centers, includes patients implanted with first-generation stents, mainly Cypher and Taxus stents, since 2003 who experienced definite late or very late stent thrombosis. The purpose of the registry, which is approved by the Food and Drug Administration and includes 478 cases of stent thrombosis, is to highlight clinical, procedural, and angiographic variables associated with late stent thrombosis (defined as >30 days from stent implantation).

Overall, 14.3% of events occurred between 30 days and 180 days, and 10.5% events occurred between six months and one year. Approximately one-quarter of stent-thrombosis events occurred between one and two years, while another 16.4% events occurred between two and three years. In total, 35% of all stent-thrombosis events occurred after three years, with events reported as late as 7.3 years after stent implantation. Of patients who experienced stent thrombosis, 67% presented with STEMI, while 22% presented with acute coronary syndrome or non-STEMI.

"The good news is the previous studies suggested a 30% mortality risk in patients who had an acute or subacute stent thrombosis, but in-hospital mortality for patients who presented with late stent thrombosis in DESERT was 3.8%," said Waksman. "At one year, the risk of death is very low, just 1.67%. The findings suggest that there might be a different mechanism for late stent thrombosis, such as late restenosis or atherosclerosis."

Waksman said that all the stent-thrombosis cases were documented by an independent core lab and all cases showed a visible thrombus on angiography in the vessel.

To heartwire , Waksman noted that nearly 30% of patients who had stent thrombosis were taking dual antiplatelet therapy at the time of the event, a percentage that roughly corresponds to the percentage of clopidogrel nonresponders. Of those not taking dual antiplatelet therapy at the time of the stent thrombosis, 44% of patients had stopped the drugs within five days of the clinical events. In a multivariate analysis, younger age, smoking, black ethnicity, multivessel disease, STEMI, or saphenous vein graft lesions were all associated with an increased risk of late stent thrombosis, suggesting that these patients might be candidates for more potent anticoagulation or a longer dual antiplatelet therapy regimen.

Waksman said the group is currently analyzing the angiographic data and hopes to present them at the American Heart Association 2011 Scientific Sessions in Orlando, FL next week.


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