Omission of aspirin from antiplatelet regimen: The WOEST study

August 28, 2012

Lifelong anticoagulation is necessary for the prevention of stroke in patients with rhythm disturbances and with mechanical valves. Patients who have a coronary stent implanted also need the antiplatelet drugs aspirin and clopidogrel to prevent the rare but lethal complication of stent thrombosis. For patients taking oral anticoagulant drugs (for atrial fibrillation or mechanical valve) who also have to undergo coronary stenting, the optimal antithrombotic treatment is still unknown, even though the use of all three drugs (oral anticoagulants, aspirin and clopidogrel) seems logical for the prevention of stroke and stent thrombosis. However, treatment with all three drugs often causes serious bleeding complications and the frequent need to discontinue the aspirin and clopidogrel.

Now, results from the WOEST study (What is the Optimal antiplatElet and anticoagulant therapy in patients with and coronary StenTing) show that a strategy of adding clopidogrel only to anticoagulants (and omitting aspirin) causes less bleeding and is safe with respect to preventing thrombotic and thromboembolic complications such as stent thrombosis. The results were presented here today at ESC Congress 2012 by Dr Willem Dewilde, TweeSteden Hospital, Tilburg, the Netherlands, who said that "WOEST is the first study demonstrating that the omission of aspirin in patients treated with oral anticoagulants and having a is safe".

He explained that the WOEST study was designed to resolve this specific dilemma of cardiology - the optimal antithrombotic treatment for patients taking oral anticoagulant drugs who also have to undergo coronary stenting. The study hypothesis was that aspirin could be omitted. "This would possibly lead to less bleedings," said Dr Dewilde, "but hopefully would not increase the risk of thrombotic complications such as stent thrombosis."

The study took place between November 2008 and November 2011, when 573 patients already treated with oral anticoagulants for atrial fiblillation or mechanical valves and undergoing coronary stenting were prospectively randomised to two groups: one given additional clopidogrel only (double therapy group), or a second given additional and aspirin (triple therapy group). Each was followed for one year. The investigator-driven study was conducted in 15 hospitals in the Netherlands and Belgium, and was sponsored by the St Antonius Hospital, Nieuwegein, the Netherlands.

Results showed that at one-year follow-up after coronary stenting, the dual therapy group had less bleeding (Figure 1) and a lower overall mortality rate (Figure 2) than the triple therapy group. Furthermore, there was no increase in the occurrence of myocardial infarction and stent thrombosis as compared with the triple therapy group.

"Thus," said Dr Dewilde, "the WOEST study demonstrates that omitting leads to less bleedings but does not increase the risk of stent , stroke or myocardial infarction. Although the number of patients in the trial is limited, this is an important finding with implications for future treatment and guidelines in this group of patients known to be at high risk of bleeding and thrombotic complications."

Explore further: Antiplatelets: 1 person, 1 dose?

More information: 1. The MAZE procedure is a surgical treatment of atrial fibrillation in which several incisions are made on the left and right atriums of the heart to form scar tissue. The scar tissue inhibits the transmission of electrical signals, thereby reducing the incidence of the arrhythmia.

Related Stories

Antiplatelets: 1 person, 1 dose?

April 14, 2011

An international consortium of scientists, including major contributions from the Montreal Heart Institute, demonstrates that the "one-size fits all" strategy of uniformly doubling the dose of an antiplatelet drug, clopidogrel, ...

Recommended for you

Artificial heart design features porous plastic foam

October 2, 2015

Artificial hearts with multiple moving parts increase the chance of failure; scientists have worked up a device which is a single piece. No less interesting is the material they used; the team is taking a page out of soft ...

What powers the pumping heart?

September 25, 2015

Researchers at the Ted Rogers Centre for Heart Research have uncovered a treasure trove of proteins, which hold answers about how our heart pumps—a phenomenon known as contractility.

Sticky gel helps stem cells heal rat hearts

September 24, 2015

A sticky, protein-rich gel created by Johns Hopkins researchers appears to help stem cells stay on or in rat hearts and restore their metabolism after transplantation, improving cardiac function after simulated heart attacks, ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.