Grant: Project Grant

Atrial fibrillation (AF) is a common heart rhythm disorder that causes one out of six strokes. Prevention of strokes in AF is achieved through the use of blood thinners such as coumadin. Although blood thinners are effective, they are limited by the risk of serious bleeding, by physician and patient unwillingness to use, and by noncompliance and discontinuation. The left atrial appendage is a structure on the upper chamber of the heart that is the most common source of stroke in patients with AF. This structure is easily accessible for removal during open heart surgery, and has been a target of interest for stroke prevention. However, there is currently no definitive evidence that removing it prevents strokes. The LAAOS III trial randomly (like the flip of a coin) assigns patients with AF undergoing heart surgery for other reasons to have their left atrial appendage closed or not closed. These patients will be treated in the usual manner except for this small procedure which has been shown to be quite safe. Having successfully recruited 2300 participants into the trial supported by multiple seed and bridge grants, we now seek full funding to complete recruitment to the full 4,700 participants required to know if left atrial appendage closure works. The LAAOS III trial will determine if closing the left atrial appendage can reduce stroke and other complications in addition to usual therapy. A positive study will change the way heart surgery is performed on patients with AF and result in a large reduction in the number of strokes in Canada. Further, it will promote further research into this approach that could be applied beyond AF patients undergoing heart surgery.