AHA 2016: PIONEER Study for Afib, PCI Patients Meets Goal

Coronary artery disease patients often receive antiplatelet therapy, such as aspirin, to avoid heart attacks, while atrial fibrillation patients typically receive blood thinners to reduce the risk of stroke. For those who have both conditions, all these medications add up to a risk of bleeding.

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A late-breaking clinical trial presented at the American Heart Association's Scientific Sessions 2016 investigated the safety of a different combination approach to prevent bleeding effects for Afib patients undergoing percutaneous coronary intervention (PCI) with stenting.

The study was also released in the New England Journal of Medicine.

Geoffrey Barnes, M.D., M.Sc., a cardiologist at the University of Michigan's Frankel Cardiovascular Center and a researcher at U-M's Institute for Healthcare Policy & Innovation, was at AHA and shares why this trial has such a large impact for patients.

What's important about the PIONEER AF-PCI trial?

Barnes: About 4 million people in the U.S. have atrial fibrillation, or Afib, the most common form of arrhythmia, and about a quarter of those people have coronary artery disease as well. That means the implications of this research could affect around a million patients throughout the country who want to avoid bleeding and use the most advanced drugs.

Current guidelines recommend treating this population with a triple therapy of a vitamin K antagonist like warfarin, known as Coumadin, along with dual antiplatelet therapy, such as aspirin and clopidogrel, but that regimen leads to major bleeding in some people.

It's very important to decide how many anti-thrombotic agents and at what intensity we should be treating patients.

Many patients are requesting newer drugs like rivaroxaban, or Xarelto, in place of warfarin, which is notoriously difficult to manage.

What did the study investigate?

Barnes: It's important to remember that this was a study about safety, not efficacy.

The maker of Xarelto, a nonvitamin K antagonist oral anticoagulant (NOAC), funded this research to compare bleeding events with Xarelto to bleeding events with warfarin in Afib patients undergoing PCI.

The study included 2,124 subjects, assigned to one of three groups:

• Two medications: Low-dose rivaroxaban plus clopidogrel, known as Plavix, without aspirin

• Three medications, lower dose: Very low-dose rivaroxaban plus dual antiplatelet therapy (such as aspirin and clopidogrel)

• Three medications, standard dose: Triple therapy with vitamin K antagonist, such as warfarin, plus dual antiplatelet therapy (aspirin and clopidogrel)

Were you surprised by the results?

Barnes: No, I wasn't. Both of the rivaroxaban groups were designed to reduce the risk of bleeding, either through a very low dose of rivaroxaban or through limiting the number of total drugs being taken.

We are reassured that there were no differences in the number of strokes or heart attacks in all three groups, but that was not the primary outcome the study was looking for, so more data are needed.

For my patients who currently use rivaroxaban to prevent a stroke, we now have good data about how to safely treat them if they need a stent placed in their heart.

This has been a long journey. What's next?

Barnes: There is still more to learn about how to safely care for patients who have a risk of stroke and a risk of heart attack. This is especially true for patients with atrial fibrillation who are already taking a different blood thinner to prevent strokes.

Two more studies, RE-DUAL and AUGUSTUS, are similar to PIONEER AF-PCI and will investigate those other drugs for this population as well.

Disclosure: Barnes does consulting work for Janssen Global Services, Bristol-Myers Squibb and Pfizer.