Lessons from Medtronic’s Define AFib study of implantable cardiac monitors

Medtronic‘s study of Linq implantable cardiac monitor (ICM) devices in atrial fibrillation (AFib) patients offers important lessons for other device developers, says the cardiac electrophysiologist who chaired the Define AFib clinical study steering committee.

Dr. Jonathan Piccini, a professor of medicine and population health at Duke University Hospital and the Duke Clinical Research Institute, has been involved with the first-of-its-kind app-based study — which enrolled its first patients in 2021 — for more than five years.

“Define AFib is not only a really important study to help us understand how atrial fibrillation behaves in patients, but it’s also a building block for the clinical trials of the future,” Piccini said in an interview with Medical Design & Outsourcing.

The following has been lightly edited for space and clarity.

What’s the significance of the Define AFib study for patients and for the technology?

Piccini: “There are a lot of different ways you can think about Define AFib. On one hand, you could say it’s a study about implantable loop recorders and the information they bring that can be used for monitoring patients and understanding their disease trajectory as well as management and treatment of their conditions. Another way to look at the study is as a first-in-class innovative study design, where as much information as possible is sourced from patients in their usual routine and not under the auspices or in the settings of dedicated research visits where we intermittently collect information. Define AFib was very unusual in that patients who got one of these implantable loop recorders as part of their regular clinical care were invited to participate, and once they were informed about the study and they agreed to participate, essentially everything was remote. It wasn’t a sightless study, because a sightless study truly means they never stepped foot in a brick-and-mortar facility. In this case, they were in a brick-and-mortar facility for that original implant, but everything after that was really all remote. As a result it had as minimal a burden as possible on patients. More than that, the study was designed largely through patient feedback. The study team reached out to patients and said, ‘You have this implantable monitor. What type of information do you find helpful for you managing your illness?’ The entire app that the patient had displayed information in a very patient-centered way.”

What about this study made it different than more traditional clinical trials?

Piccini: “The concept was wearables are becoming more and more common. They’re collecting a significant amount of information on patient health. Smartphones are becoming more and more common. They too are collecting lots of information, not just necessarily health information, but also information like someone’s location. So if someone goes into a healthcare facility, does that mean they’ve been hospitalized? There’s so many different pieces of innovation. One was making sure that patients were informed and that when they agreed to participate, they understood what information the study was going to use to help us understand the disease better. For example, part of this geofencing was that if a patient provided permission and their phone was in a healthcare facility for a certain period of time, that launched a query to see if the patient had been hospitalized. There were quality of life surveys that if a patient’s device picked up atrial fibrillation at a certain interval, it would send a patient a questionnaire that assessed how their quality of life activity levels were, those types of things. There’s so many things we learned, and it would be hard to go through all of them, but some of the highlights are that we we definitely did see that when patients had more AFib, they tended to have reductions in their quality of life. We learned that the information from the devices was not overwhelming to patients or their healthcare providers. We often hear concerns about information overload, but by and large the feedback we received was the additional information was helpful and not overly burdensome.”

What was the major takeaway for AFib from this study?

Piccini: “The main scientific finding presented at the AF Symposium is when you take basic information about someone’s atrial fibrillation combined with information about their medical conditions — do they have heart failure, do they have diabetes, do they have high blood pressure — and you combine that with continuous information about their heart rhythm and how often they’re in atrial fibrillation, how long the episodes of atrial fibrillation are, all of that information together, you can begin to be able to predict how likely someone is to need care for their atrial fibrillation. Why is that important? When they need care, won’t they just show up for it? That’s one view you could take. But a much better way to deliver healthcare is to make sure the right treatment gets to the right patient at the right time. So it would be much better if we can anticipate that someone’s going to need a change in their medication so we can avoid them needing to come in for an urgent last-minute clinic visit or avoid them going to the emergency room or being hospitalized.”

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What did you learn from this study that could be helpful for device developers planning their own trials?

Piccini: “One worry we had was if you’re in a study and your phone every now and then asks you to answer some questions for the study, are you really going to do it? We were very pleasantly surprised. Our survey response rates were very high throughout the study. We think that’s a reflection of the fact that these are patients who really wanted to help improve our knowledge of atrial fibrillation so in the future we get even better at treating the illness. That was one pleasant surprise. I wouldn’t say it was a disappointment, but something I think we need to continue to work on is that the vast majority of individuals have a smart device, but they may not have the specific smart device that a given study is using. In the future we need to focus on interoperability so no matter what type of device someone has, they can still participate in the study. And it is true that remote studies still have barriers. If you have a hard time navigating electronic enrollment or setting up things on your phone, those can be barriers in these types of studies. No matter what type of information you’re collecting, you still want to be able to validate things in individuals medical records. If a patient says they have this condition or that condition or they went to the emergency room, you want to be able to verify that and the technologies we have to do that are still very labor intensive. Having ways to quickly validate things electronically is something else we’re going to need to pay close attention to in the future.”

How did you achieve such a high response rate?

Piccini: “There’s three reasons. The first is we really leaned heavily into patient engagement. The study team aggressively sought out patient opinion, asking, ‘Will this be burdensome? Do you think your peers will react favorably to this?’ There was a lot of engagement to get advice from patients in the very beginning. The second reason is we used validated surveys that are designed to collect the maximal amount of information while avoiding survey fatigue to every extent possible. And then the third reason is — and this is something we often don’t talk about — these are patients who said, ‘I want to help.’ They were highly motivated to make sure the study could learn as much about atrial fibrillation as possible. And we have just an incredible amount of data, thousands and thousands and thousands of observations and data points from the study participants that we hope is going to continue to contribute to the body of knowledge around AFib for a very long time to come.”

More from our interview with Piccini: What is minimally invasive medtech? Device engineers, executives and experts offer their min-vasive philosophies