Willem Dewilde presenting WOEST study at Hotline press conference III.
Commenting on the results, presenter Willem Dewilde said that WOEST was the first ever study to demonstrate that it was safe to omit aspirin in these patients, and that the results could have major treatment implications.
“This is an important finding with implications for future treatment and guidelines in a group of patients known to be at high risk of bleeding and thrombotic complications,” said Dewilde, from TweeSteden Hospital in the Netherlands. Session chairman Keith Fox from the University of Edinburgh added that the results could mean a reduction in the use of aspirin in PCI patients.
“There was very limited evidence prior to this study, and I think the community will take this seriously,’ said Fox. “Practice in cardiology has been so built around aspirin, that it’s taken some courage to do without it.”
Dewilde reaffirmed that long-term OAC is obligatory for the prevention of stroke in most patients with atrial fibrillation (AF) and with mechanical heart valves. More than 30% of these patients also have ischemic heart disease and require aspirin and clopidogrel for coronary stenting. Triple therapy (OAC, aspirin, clopidogrel) is recommended in the guidelines, said Dewilde, but often causes major bleeding complications and the frequent need to discontinue the aspirin and clopidogrel.
The aim of WOEST, he added, was to test the hyypothesis that, in patients on OAC having PCI, clopidogrel alone was superior to the combination of aspirin and clopidogrel with respect to bleeding and thrombotic risk.
A total of 573 patients already treated with OAC for AF or mechanical valves and undergoing coronary stenting were randomised to two groups: additional clopidogrel only (double therapy group) or additional clopidogrel and aspirin (triple therapy).
Fifteen hospitals in the Netherlands and Belgium took part and each group was followed for one year.
Results showed that the dual therapy group had significantly less bleeding (19.5%) than the triple therapy group (44.9%), and a lower mortality rate (2.6% vs 6.4%).
In the dual therapy group, there was also no increase in the occurrence of MI (3.3%) and stent thrombosis (1.5%) compared with the triple therapy group (MI=4.7%, ST=3.2%), suggesting that the omission of aspirin does not compromise safety.