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Can Apple Watch reduce patients’ reliance on blood thinners?

Northwestern awarded first-ever national grant to study wearables, stroke prevention in patients with atrial fibrillation
Apple Watch
The study will be using the scientifically validated, innovative heart health features on Apple Watch, through a contribution from Apple. Apple will also provide guidance on the development of the study application.

Northwestern University and Johns Hopkins University have been awarded a multi-million-dollar grant from the National Heart, Lung, and Blood Institute to study a “pill-in-pocket” strategy to prevent stroke in patients with atrial fibrillation (AFib), the most common heart rhythm disorder in adults.

Currently, patients with AFib are treated with continuous blood-thinning medication to reduce their risk of blood clots and stroke. This new National Institutes of Health-funded trial will incorporate the use of an app on Apple Watch to monitor AFib to attempt to reduce patients’ continuous and lifelong reliance on blood-thinning medication. 

The approximately $37 million award will fund the seven-year trial, called the Rhythm Evaluation for AntiCoagulaTion (REACT-AF) trial. Funds awarded by the NIH for grant years two through seven are subject to successful completion of milestones during grant year one.

The study is a collaboration between Northwestern University Feinberg School of Medicine and the American Heart Association. The study will be using the scientifically validated, innovative heart health features on Apple Watch, through a contribution from Apple. Apple will also provide guidance on the development of the study application.

Using the app on Apple Watch and an accompanying app on iPhone, patients in the trial will be able to target blood-thinning medication use for a limited period of time and only in response to a prolonged episode of AFib, thus creating personalized care unique to each patient.

“If proven effective, this new treatment paradigm will fundamentally change the standard of care for the millions of Americans living with AFib,” said principal investigator Dr. Rod Passman, director of the Center for Arrhythmia Research and a professor of medicine in the division of cardiology at Feinberg.

“Many of these patients are on blood thinners for the rest of their lives even if they have infrequent episodes of atrial fibrillation,” Passman said. “If we can show this strategy is equally protective against stroke and reduces bleeding, that could save lives, reduce cost and improve quality of life.”  

For eight years, Passman has been studying solutions to end the standard “one-size-fits-all” practice of prescribing lifelong blood thinners (anticoagulants) to everyone with AFib. 

The trial secures Northwestern as the world leader in wearable devices for treating atrial fibrillation. 

2.5 to 5 million
The number of Americans affected by AFib

While it is estimated that between 2.5 and 5 million Americans are living with AFib today, that number is estimated to grow to 12.1 million by 2030. Worldwide, the estimated number of individuals with AFib in 2010 was 33.5 million, according to a 2013 study.

Targeting when to use blood thinners to limit reliance

AFib is a heart rhythm disorder characterized by fast and irregular heartbeats from the upper chambers of the heart. People with AFib have increased risk of stroke, so many are continuously treated with blood-thinning medication to reduce that risk. But this treatment also raises the risk of bleeding, according to Passman, and balancing the risks and benefits can be challenging for both patients and physicians. 

However, some patients with AFib have infrequent episodes of irregular heart rhythm either on their own or as the result of medications or procedures. Current evidence suggests the risk of stroke increases in the weeks following an episode of AFib then returns to a baseline, raising the possibility of intermittent blood-thinner treatment. 

Since many individuals have no symptoms during an episode of AFib, the new trial will employ Apple Watch to monitor heart activity and notify patients when they’re entering an episode. 

When notified, patients will take blood-thinning medication for a few weeks during the high-risk window for stroke and can discontinue if they do not have another episode. This “pill-in-pocket” approach could protect patients against stroke while reducing bleeding events and the cost of Afib treatment, Passman said. 

“We think advances in technology will allow us to personalize this care,” Passman said. “Why should patients expose themselves to the risk and cost of these drugs when they may not be benefiting?”

Revealing important AFib info, no matter what

The seven-year trial will recruit 5,400 patients, randomizing them to receive either the current standard of care or treatment directed by the app on Apple Watch. The trial will also examine whether the app can reduce major bleeding events compared to continuous therapy. 

Secondary aims include measuring patient satisfaction and health care resource utilization. Importantly, the trial will reveal important information about AFib no matter the findings, according to Passman. 

“While most data suggest the atrial fibrillation rhythm itself causes the stroke, there’s an alternative hypothesis that the risk remains even when the rhythm itself goes away,” Passman said. “If this strategy is not equally effective, then perhaps we should reconsider whether the rhythm of the heart causes stroke or is simply a marker for some underlying mechanism.”

This grant application was administratively supported by the Northwestern University Clinical and Translational Sciences (NUCATS) Institute, the Bluhm Cardiovascular Institute’s Clinical Trials Unit and the Trial Innovation Network.

Northwestern is the lead study site. Partnering institutions include Johns Hopkins, Stanford University and University of California at San Francisco.

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