Skeptic’s Corner: Experts Debate Aspirin Use in Patients with AF Receiving DES
Patients on oral anticoagulation for atrial fibrillation (AF) who receive DES should routinely forego aspirin and continue therapy with a P2Y12 inhibitor, Christopher B. Granger, MD, of the Duke Clinical Research Institute, Durham, N.C., argued in a Skeptic’s Corner debate, pointing to the greater risk of bleeding and the lack of clinical benefit with triple therapy.
But on the other side of the argument, Joanna J. Wykrzykowska, MD, PhD, of the University of Amsterdam, the Netherlands, countered that the WOEST trial supporting that approach was flawed and more data are needed before regularly dropping aspirin from the post-PCI regimen in these patients.
“We should really think hard and individualize the antithrombotic therapy for every patient based on their bleeding risk, their thrombosis risk, lesion and procedural characteristics and stent type used,” she said. “We [also] need more randomized trials.”
Making the case against aspirin
Granger reviewed prior studies showing that adding aspirin to warfarin, clopidogrel or both increases harmful bleeding by 2- to 4-fold, and in many cases without any clinical benefit. He said P2Y12 inhibitors are the therapies most important for patients undergoing stenting. In a randomized trial published in 1998, for example, the primary composite endpoint of death, TVR, angiographically evident thrombosis or MI within 30 days was lower in the patients who received aspirin plus ticlopidine, but not in those who received aspirin plus warfarin or aspirin alone.
WOEST, which included 573 patients on oral anticoagulation undergoing coronary stenting, explored whether there was a difference in bleeding when clopidogrel was used after the procedure alone or with aspirin. The rate of TIMI bleeding events (primary endpoint) was lower in the patients who did not receive aspirin (19.5% vs. 44.9%, P<.001). In addition, the secondary endpoint of thrombotic events occurred less frequently when aspirin was not included (11.3% vs. 17.7%, P=.025).
“Even before WOEST, it would have been very reasonable to omit aspirin, or at least to use it selectively when using warfarin and clopidogrel,” Granger said. “And with WOEST, while it’s not definitive, it strongly suggests harm and lack of benefit and thus tips the balance [so] that aspirin should be routinely dropped in this population.”
Clear evidence to discontinue lacking
Wykrzykowska cautioned against being too hasty in making treatment decisions based on WOEST. She noted that the trial was not powered for ischemic complications, stent thrombosis rates were high and patients were lower risk compared with those typically seen in practice. Specifically, she added, most patients had single-vessel disease, only about two-thirds received DES and only 25% to 30% had ACS as the indication for the procedure.
To illustrate her concerns regarding leaving aspirin out of the regimen, she cited two cases in which patients were discharged after stenting on oral anticoagulation and either prasugrel or clopidogrel alone only to return with stent or scaffold thrombosis. Wykrzykowska suggested that aspirin discontinuation should not become standard of care without further research to support it. Such trials are ongoing, and Wykrzykowska said she was particularly interested in seeing the results of the 8,500-patient RE-DUAL PCI trial.
Granger agreed that additional studies should clarify the issue but added that in the meantime, clinicians should at least be more willing to discontinue aspirin in patients with high risk of bleeding and low risk of stent thrombosis.
- Granger reports relationships with multiple pharmaceutical and device companies.
- Wykrzykowska reports receiving grant/research support and consulting fees/honoraria from Abbott Vascular, St. Jude Medical and Tryton Medical.