FDA Approves the AtriClip for Stroke Prevention in Atrial Fibrillation Patients

June 18, 2010 12:05 AM CT

By Christine Welniak

Doctors may now have another way to reduce the risk of stroke for their patients with afib. The U.S. Food and Drug Administration (FDA) has approved the AtriClip Gillinov-Cosgrove Left Atrial Appendage Exclusion system for atrial fibrillation patients undergoing open heart surgery. Until now, individuals who have afib have only been able to reduce their stroke risk through lifestyle changes, such as quitting smoking, or anticoagulation medication, such as warfarin.

Patients with atrial fibrillation have a five-fold higher risk of having a stroke than people who don’t have AF, according to the Framingham Heart Study, which followed 5,070 patients for 34 years. Doctors believe the higher risk is because atrial fibrillation causes blood to pool in the left atrial appendage, sometimes referred to as the LAA, which is a small pouch attached to the left atrium. When blood is caught in the left atrial appendage, clots can form. These clots can detach and travel through the blood stream and cause a stroke.

Because over 90% of clots are believed to form in the left atrial appendage, it is thought that removing (“excising”) or cutting off blood flow into (“occluding” or “excluding”) the left atrial appendage will lower the incidence of stroke for patients with afib. Surgeons can use a special stapler to remove the left atrial appendage or sew sutures to manually occlude the left atrial appendage. However, a study performed at the Cleveland Clinic showed that only 40% of 137 left atrial appendage excisions or exclusions performed using these techniques successfully closed the left atrial appendage.

There are a number of left atrial appendage occlusion devices that are available outside of the U.S., but AtriClip is the first to be approved in the U.S. Unlike catheters, which can be used to treat afib even if they do not have specific FDA approval (“labeling”) for atrial fibrillation, left atrial appendage occlusion devices other than AtriClip can only be used in the U.S. if part of a clinical trial.

AtriClip Procedure and Trial Results

To place the rectangular-shaped AtriClip device, the surgeon positions it around the left atrial appendage and then “closes” the device, much like a clamp shuts off blood supply. This prevents blood from flowing into and out of the left atrial appendage.

AtriClip’s U.S. clinical trial, EXCLUDE, met the study’s endpoints for safety (complications, such as bleeding) and efficacy (ability of the device to stop blood from flowing into the left atrial appendage). Surgeons were able to implant the device in 67 patients (95.7% of individuals in the study). No patients had bleeding related to AtriClip, and the left atrial appendage did not tear in any of the procedures. Three months after getting AtriClip, 61 patients had CT (computed tomography) and ultrasound scans and all but one patient showed complete occlusion of the left atrial appendage. Of note, stroke itself was not an endpoint in the study.

Dr. Marc Gillinov of the Cleveland Clinic, one of the inventors of the AtriClip, says, “We anticipate that this new therapy will provide a great benefit to patients with atrial fibrillation, particularly those who are at the greatest risk for stroke.”

Can Warfarin Be Stopped?

Theoretically, afib patients who have had the left atrial appendage excised or occluded should not have to take anticoagulant medication, such as warfarin. However, this hypothesis has not yet been proven conclusively. It’s unclear whether healthcare providers will discontinue anticoagulants without data showing that AtriClip does indeed reduce the incidence of stroke for individuals with afib.

Dr. Gillinov commented, “the initial experience demonstrates that AtriClip is safe and effective. We must now address the next set of questions, including the need for warfarin in a patient who has had the left atrial appendage occluded.”

AtriCure, which manufactures the AtriClip, believes the device will be available throughout the U.S. some time during the summer. The company is also working on a version of the AtriClip that could be used in a mini maze procedure.

There are several other devices that are in U.S. clinical trials. Medtronic’s Cardioblate Closure LAA Occlusion device is being studied in patients undergoing open heart surgery. AGA Medical’s Amplatzer Cardiac Plug, which is implanted by a cardiologist via a catheter, just treated the first patient in its U.S. clinical trial. Patients are randomized to receive either the Amplatzer Cardiac Plug or warfarin.

The FDA has asked for additional data on Atritech’s Watchman stroke prevention device. Results from the PROTECT AF clinical trial comparing the Watchman to warfarin were controversial. Some doctors were concerned because the safety events were double for the Watchman compared to warfarin, but these events have decreased over time due to enhanced procedures and training. Atritech is expected to begin enrolling patients in a second trial, called PREVAIL, this Fall.

Read related information:

Christine Welniak writes about atrial fibrillation and other heart diseases/conditions for patients, medical professionals, and investors.