Clinician-to-Clinician Update Clinician-to-Clinician Update

Device Assists A-fib Patients Not Eligible for Anticoagulant Use

August 2017

Atrial fibrillation (AF) presents significant health impacts, including a fivefold increase in ischemic stroke risk.1 While oral anticoagulants remain a first-line therapy for these patients, AF treatment strategies to prevent stroke risk have also focused on the left atrial appendage (LAA) as an origin of thrombosis. A projection of the left atrium that may function to relieve high pressure during left ventricular systole2, the LAA has been identified as the origin of 57% atrial clots in patients with valve disease-related AF and of up to 90% of atrial clots in those with nonvalvular AF (NVAF).3 Cardiac devices designed to occlude the LAA are now providing an added treatment strategy for reducing stroke risk in patients with NVAF.

From 14% to 44% of AF patients are unable to pursue long-term anticoagulation therapy due to elevated bleeding risk or medication interactions.3 As late as 2007, removal of the LAA was recommended to reduce stroke risk in those AF patients undergoing cardiac surgery.3, 4 Since then, methods to occlude rather than excise the LAA have been considered a preferred approach, mainly in the effort to avoid any unforeseen physiological changes that could occur after removal of the LAA in patients with high blood pressure or heart failure.2

LAA occlusion devices implanted via transcatheter procedures have been under review since the mid-2000s, and in 2015, the Food and Drug Administration approved the Watchman device (Boston Scientific) for use in patients with NVAF.5 Designed to prevent blood from entering the LAA, where most atrial clots form, the device provides a stroke-prevention intervention for NVAF patients who face a higher risk of hemorrhage associated with anticoagulants.

August-2017-Consult-Heart-Care-Feature-Article-Main-Image
— Interventional cardiologists Gregory Helmer, MD, and Ganesh Raveendran, MD, confer in a University of Minnesota Health Heart Care cardiac catheterization lab.

During a percutaneous procedure, the device is guided through a delivery catheter via the femoral vein and into the right atrium and then into the left atrium where it is introduced into the LAA and opened like an umbrella to fill the appendage. Small barbs that ring the device lock it in place. Over a period of about 45 days, scar tissue forms over the device, occluding the LAA. Transesophageal echocardiography is performed during the procedure and again at 45 days and 6 months to verify the device’s proper placement and rule out the formation of clots.6 Patients continue to take oral anticoagulants initially, but as 1 clinical trial reports, at 45 days following the procedure, approximately 92% of patients were able to stop anticoagulant medication and over 99% had discontinued it at 1 year postprocedure.5

Large clinical trials have shown the Watchman device to be as effective as warfarin in reducing stroke risk in patients with NVAF.6, 7 As clinicians adopt the procedure, outcomes have been found to improve,6 and NVAF patients with the highest bleeding risk who cannot take anticoagulants long term experience more benefit with the Watchman device than with aspirin alone.7

Cardiologists with University of Minnesota Health Heart Care have observed good outcomes with the Watchman device in treating patients with NVAF and higher risk of bleeding. See the Case Study for further discussion.

References

  1. Go AS, Hylek EM, Phillips KA., et al. Prevalence of Diagnosed Atrial Fibrillation in Adults: National Implications for Rhythm Management and Stroke Prevention: the AnTicoagulation and Risk Factors In Atrial Fibrillation (ATRIA) Study. JAMA. 2001;285(18):2370-2375. doi:10.1001/jama.285.18.2370
  2. Al-Saady N, Obel O, Camm A. Left atrial appendage: structure, function, and role thromboembolism. Heart. 1999;82(5):547-554.
  3. Onalan O, and Crystal E. Left atrial appendage exclusion for stroke prevention in patients with nonrheumatic atrial fibrillation. Stroke. 2007;38 (2 suppl):624-630.
  4. Onalan O, Lashevsky I, Hamad A, and Crystal E. Nonpharmacologic stroke prevention in atrial fibrillation. Expert Rev Cardiovasc Ther. 2005;3(4), 619-633.
  5. U.S. Food & Drug Administration. Watchman LAA closure technology - P130013. https://www.fda.gov/medicaldevices/productsandmedicalprocedures/deviceapprovalsandclearances/recentlyapproveddevices/ucm440621.htm Apr 2, 2015. Retrieved June 21, 2017.
  6. Holmes DR, Kar S, Price MJ, et al. Prospective randomized evaluation of the Watchman left atrial appendage closure device in patients with atrial fibrillation versus long-term warfarin therapy: the PREVAIL trial. J Am Coll Cardiol. 2014;64(1):1-12.
  7. Holmes DR Jr, Doshi SK, Kar S, et al. Left atrial appendage closure as an alternative to warfarin for stroke prevention in atrial fibrillation: A patient-level meta-analysis. J Am Coll Cardiol. 2015;65(24):2614-2623.

When to refer

University of Minnesota Health Heart Care clinicians treat all forms of atrial fibrillation, from straightforward cases to those involving many co-occurring heart conditions. Our skilled teams provide comprehensive care using the most up-to-date guidelines for antiarrhythmic medications, ablative procedures, and percutaneous coronary interventions, including the use of robotics when required. Our physicians and nurse practitioners with the M Health Atrial Fibrillation Center, spread across 8 locations and one of the largest such centers in the state, have been recognized with Gold, Silver, and Bronze Get with the Guidelines Awards from the American Heart Association.

Multidisciplinary, Collaborative Care

At University of Minnesota Health Heart Care, we understand that primary care providers see many patients with a range of different heart conditions. We rely on referring providers to help us form a team that provides comprehensive care for patients. We work with referring physicians and their offices to create an intact line of efficient communication about each step of treatment. We address the widest spectrum of heart issues, and our teams include interventional cardiologists, electrophysiologists, pediatric cardiologists, transplant surgeons, specialist nurse practitioners, and other heart health professionals. Our physicians remain at the forefront of research, clinical trials, and new technology for treating heart disease and were among the first in the nation to perform heart transplants, cardiac resynchronization, and, recently, robotic percutaneous coronary intervention. We are committed to forming a partnership with referring providers to provide comprehensive, collaborative care for all patients with heart health needs.

To request a free copy of the 2017 University of Minnesota Health Adult Specialty Directory, visit mhealth.org/for-medical-professionals/adult-specialty-directory.

To find current clinical trials available through University of Minnesota Health providers: studyfinder.umn.edu.

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