Burden of Atrial Fibrillation and Transition to NOACs

Manesh Patel, MD: Welcome to Beaver Creek, Colorado. I’m here with colleagues as we attend the Beaumont Cardiovascular Conference. It’s a great conference, and we hope to have a lot of people join us in the future. Today we’re talking about some important topics we hope you’ll enjoy with us.

Over the last decade, the landscape of stroke prevention in patients has rapidly changed with the introduction of these non—vitamin K oral anticoagulants, and they’re the topic of our conversation today. They specifically target areas such as the IIa or Xa as inhibitors. Our discussion today focuses on available factor Xa inhibitors and the various trial data that establish their clinical uses in managing cardiovascular risks of our patients.

I am Dr Manesh Patel, a professor of medicine and the chief of the Division of Cardiology in the Department of Medicine at the Duke University School of Medicine in Durham, North Carolina.

I am joined, as I said, by several colleagues. I’ll start on the right here with Dr Robert Califf, head of clinical policy and strategy at Verily life sciences and Google Health. And he’s an adjunct professor at Duke and Stanford Medicine working out of San Francisco, California. Rob, thanks for joining us.

Robert M. Califf, MD, MACC: Good to be here, Manesh.

Manesh Patel, MD: We have Dr Bernard Gersh, who’s a professor of medicine at the Mayo Clinic College of Medicine and Science in Rochester, Minnesota. Welcome.

Bernard J. Gersh, MBChb, DPhil, MACC: Thank you. I’m also an adjunct professor at Duke.

Manesh Patel, MD: We’re excited to have you and glad to have you as also an adjunct. And Chris Granger, who’s a professor of medicine in both the School of Medicine and in the School of Nursing, important for us, at Duke University School of Medicine in Durham, North Carolina. Chris, thanks for joining us.

Christopher Granger, MD: Thanks, Manesh.

Manesh Patel, MD: Last but not least, Sean Pokorney, who’s an assistant professor of medicine at Duke University. He’s been involved in a lot of this work. Thanks for joining us, Sean.

Sean D. Pokorney, MD: Thanks for having me.

Manesh Patel, MD: Thank you all for joining us. Let’s begin. The first thing to think about is that it’s been 10 years since the first trial data started out about these agents, these non—vitamin K oral anticoagulants. Sitting here in 2020, the question is sort of what have we learned in these 10 years. Maybe I take us back to 2010 or so and say where were we. Maybe you start by telling us, Chris, what the burden of AF [atrial fibrillation] was and what we were thinking about as an opportunity to treat these patients, both locally and globally.

Christopher Granger, MD: Manesh, it’s a huge medical problem and largely related to the aging of the population. There are about 5 million people in the United States who have atrial fibrillation, and atrial fibrillation is responsible for about 1 of 5 strokes. The remarkable thing is these treatments to prevent stroke for atrial fibrillation are some of the most effective treatments we have in all of medicine. Even warfarin, especially when used well, prevents about two-thirds of strokes for patients with atrial fibrillation. Importantly, the historic data with warfarin also showed about a 25% reduction in mortality. I don’t think most people remember that. Oral anticoagulation, even with warfarin to prevent strokes for atrial fibrillation, was extremely important. It was very difficult to use, and so many patients had trouble staying in the target therapeutic INR [international normalized ratio] range and had problems with interactions with drugs and food interactions and the regular monitoring. All kinds of challenges with the use of warfarin that made people really excited about these non—vitamin K oral anticoagulants as they came into the horizon.

Manesh Patel, MD: Sean, you’re an electrophysiologist. Maybe you can tell us from your perspective what’s the growing tide of atrial fibrillation, both from a clinical and economic burden, that you see?

Sean D. Pokorney, MD: Atrial fibrillation is obviously a huge public health issue. It’s the most common sustained arrhythmia in the world. It’s the most common reason for arrhythmia-related hospitalizations in the world. With the aging population, we just see rapidly increasing number of atrial fibrillation patients. One of the big challenges is that although we have excellent medications to prevent stroke in this patient population, they’re really underutilized. The data show that about 50% to 60% of patients that have a guideline indication for stroke prevention are actually treated with oral anticoagulant.

We thought that when warfarin ceased to be the only option once we had these NOACs [novel oral anticoagulants] available that that would really change and that we would see this huge upswing in the proportion of patients that were treated. Unfortunately, we really haven’t seen that. What we’ve mostly seen is a transition of treating patients with the NOACs instead of treating them with warfarin, so patients have been transitioned over to NOACs, and the new starts are predominantly NOAC and not warfarin. We’ve seen the proportion of patients treated increase by only about 2% a year since the NOACs have been used in clinical practice.

Bernard J. Gersh, MBChb, DPhil, MACC: I just wanted to reinforce something that.

Manesh Patel, MD: One of the things that I wonder a lot about you could help us with, because I know you’ve thought a lot about it is the mechanism by how these patients with atrial fibrillation are developing stroke. Some of it might be atrial fibrosis, a clot, or other mechanisms. What are your thoughts on that?

Bernard J. Gersh, MBChb, DPhil, MACC: I think it’s all of the above. I just wanted to reinforce something that Sean said. In the National Health Service in the United Kingdom and a couple of other systems, atrial fibrillation is the single most major driver of costs. The other thing, with all the changes that have taken place over the last 10 years, 1 thing that hasn’t changed is people don’t take drugs that work. I mean, there is warfarin, it worked as Chris pointed out. It was very effective. It had its limitations, but people just don’t take it—or not in the quantities they should.

Transcript edited for clarity.