MUNICH – Patients who require chronic oral anticoagulant treatment and received a coronary stent had significantly fewer bleeding events and better outcomes if they received only added clopidogrel than if they were treated with clopidogrel plus aspirin on top of their anticoagulant in the WOEST trial.
As the first study to prospectively test the best combination of antiplatelet drugs to use on top of anticoagulant treatment in patients following coronary stenting, experts hailed the finding as important evidence to address a common and vexing clinical situation.
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Dr. Willem Dewilde
"We propose that a strategy of oral anticoagulants plus clopidogrel, but without aspirin could be applied in this group of high-risk patients who are on an oral anticoagulant and undergo percutaneous coronary intervention," said Dr. Willem Dewilde, lead investigator for the study, at the Annual Congress of the European Society of Cardiology.
"We are faced with a huge clinical problem, with an increasing number of patients with atrial fibrillation who undergo stent procedures, so this finding has major implications," commented Dr. David R. Holmes Jr., professor of medicine and a cardiologist at the Mayo Clinic in Rochester, Minn. "Bleeding is such a huge issue, and we now have scientific data that says [withholding aspirin] is safe and produces less bleeding."
"The taboo against discontinuing or omitting aspirin has been broken," commented Dr. Marco Valgimigli, director of the coronary catheterization laboratory at the University Hospital of Ferrara (Italy).
The WOEST (What is the Optimal Antiplatelet and Anticoagulant Therapy in Patients with Oral Anticoagulation and Coronary Stenting) trial enrolled 573 patients who required chronic oral anticoagulant treatment and were scheduled for coronary stenting at 15 centers in the Netherlands and Belgium. The patients averaged about 70 years of age, and about 80% were men. A total of 70% received daily, oral treatment with an anticoagulant for atrial fibrillation or flutter, about 10% for a mechanical valve, and the remaining 20% had other reasons for their regimen, including treatment of a pulmonary embolus. All patients received warfarin or another oral anticoagulant such as acenocoumarol. About two-thirds of the patients received a drug-eluting coronary stent, with the remainder receiving a bare-metal stent.
Following stenting, the researchers randomized patients to a regimen of their oral anticoagulant plus 75 mg clopidogrel daily (dual therapy), or their oral anticoagulant, clopidogrel, and 80 mg aspirin daily (triple therapy). The antiplatelet part of the regimen continued for at least 1 month in patients who received a bare-metal stent and for a year in those who got a drug-eluting stent.
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Dr. Marco Valgimigli
After a year of follow-up, the incidence of the primary end point – total bleeding events – occurred in 20% of the 279 evaluable patients who received dual therapy and in 45% of 284 evaluable patients on triple therapy, a statistically significant difference, reported Dr. Dewilde, a cardiologist at TweeSteden Hospital in Tilberg, the Netherlands. The study’s secondary end point – the combined rate of death, myocardial infarction, target vessel revascularization, stroke, or stent thrombosis – occurred in 11% of patients on double therapy and 18% of those on triple therapy, a statistically significant difference.
Patients on dual therapy had a significantly lower rate of all-cause death, compared with the triple-therapy patients, 3% compared with 6%, and numerically lower levels of stent thrombosis, stroke, and myocardial infarction, although the differences for these individual end points were not statistically significant.
The dual-therapy patients also had significantly lower rates of minimal or minor bleeds, measured by the TIMI (Thrombolysis in Myocardial Infarction) criteria, and the rate of TIMI major bleeds was also lower on dual therapy, but not significantly. The dual-therapy patients had strikingly lower numbers of bleeds at gastrointestinal sites and skin sites, compared with the triple-therapy patients.
"TIMI minimal and minor bleeds are anything but minor from a clinical standpoint," noted Dr. Valgimigli. "Double therapy with clopidogrel and warfarin seems a very reasonable therapy based on WOEST, especially in DES-treated patients."
Dr. Dewilde and Dr. Holmes said that they had no disclosures. Dr. Valgimigli said that he has served on the speakers bureau for AstraZeneca, Eli Lilly, Iroko, and other companies that market vascular devices. He has also been on advisory boards for Eli Lilly, and several companies that make vascular devices. Dr. Smith said that he had no disclosures.