Letter from the Editor in Chief

DOI: 10.19102/icrm.2015.060301

MOUSSA MANSOUR, MD, FHRS, FACC

A Prospective Review on Stroke Prophylaxis in Atrial Fibrillation

Editor-in-Chief

Dear Reader,

The field of atrial fibrillation has been rapidly evolving. Since the introduction of pulmonary vein isolation in the late 90's by Dr. Haissaguerre and his colleagues this field has exploded with reports describing different techniques and technologies for perfecting the ablation procedure, improving the success rate, and reducing complications. Over the past few years, another aspect of atrial fibrillation management, stroke prevention, has been gaining momentum and preoccupying a large number of investigators. The fact that atrial fibrillation is a major cause of stroke is not new. However for many years the only available approach to prevent stroke was the use of warfarin. More recently, four novel oral anticoagulants were introduced in the US and other countries. In addition, there has been a significant interest in device-based approaches for stroke prevention.

Antithrombotic therapy is crucial for prevention of stroke in patients with atrial fibrillation. Drug treatment with warfarin is associated with significant management issues, such as an unpredictable dose response necessitating dose adjustments, frequent laboratory monitoring and multiple interactions with other drugs. Despite following best practices, warfarin is associated with limited efficacy and increased risk of hemorrhage. Due to these limitations a significant effort has been devoted towards development of newer anticoagulants. Dabigatran, Rivaroxaban, Apixaban, and more recently Edoxaban have been approved by the FDA for the prevention of stroke in patients with AF. These newer agents possess highly predictable pharmacokinetic and pharmacodynamics properties which allow a fixed dosing regimen and also eliminate the need of routine laboratory monitoring. Four landmark clinical studies, RE-LY, ROCKET AF, ARISTOTLE, and ENGAGE AF, demonstrated the effectiveness of these agents and their advantage in many aspects compared to warfarin.

In parallel to the development of novel anticoagulants, there has been a strong interest in the search for device-based approaches for stroke prevention. The left atrial appendage (LAA) is a prominent source of cardioembolic stroke in patients with nonvalvular atrial fibrillation (AF) and different techniques using diverse devices for the closure of the left atrial appendage have been developed over the past few years for stroke prophylaxis in AF. The Watchman device has been studied in randomized clinical trials with favorable results including mortality reduction when compared to warfarin, and is currently being considered for approval by the FDA. The Ampltazer cardiac plug (ACP) has been used in Europe extensively. A recent study outside the US enrolled more than 1,000 patients and showed a reduction in the observed rate of stroke with the ACP compared to an expected rate of stroke. The Coherex Wavecrest device is undergoing early clinical investigation in Europe. The epicardial Lariat device has been used extensively in the US and Europe, and many studies demonstrated its effectiveness in reducing stroke compared to an expected rate of stroke in the population studied. The surgical Atriclip has been FDA approved since 2010 and has been used widely in patients undergoing heart surgery and more recently in standalone surgical left atrial appendage closure.

Despite all the positive findings of the studies mentioned above, a number of questions remain unanswered. Are the novel anticoagulants equivalent? Is there a need for head-to-head comparison of the different agents? Who are the best candidates for left atrial appendage closure? How does endocardial left atrial closure compare to epicardial ligation? All these questions and others will stimulate the design of clinical studies the answers of which will help us to better protect our patients from stroke.

On behalf of our esteemed editorial board, we formally invite you to share your experiences through original manuscript contributions which examine and demonstrate optimal techniques, tips and tricks, and problem solving strategies in the performance of LAA closure procedures. I will provide commentary on selected manuscripts within my editor's letter. It is through an open exchange of ideas and experiences, that enable us to better serve our patients, and we welcome the continually contributions from you, the reader, who will play an integral role in establishing answers to these key questions.

Finally I would like to conclude by hoping for an early arrival of spring which has been long awaited for us in the Northeast.

Warm regards,

Moussa Mansour, MD, FHRS, FACC
Editor-in-Chief
The Journal of Innovations in Cardiac Rhythm Management
MMansour@InnovationsInCRM.com
Director Cardiac Electrophysiology Laboratory,
Director Atrial Fibrillation Program
Massachusetts General Hospital
Boston, MA