Closing Left Atrial Appendage Shown to Reduce Stroke Risk From Atrial Fibrillation
March 19, 2017—For patients with atrial fibrillation (AF), closing the left atrial appendage as an add-on procedure during cardiac surgery was associated with a 40% reduction in the risk of thromboembolism according to an observational study presented by Lead Investigator Daniel J. Friedman, MD, at the American College of Cardiology’s (ACC) 66th annual scientific session in Washington, DC.
This report from the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery database evaluates the comparative effectiveness of left atrial appendage occlusion among AF patients undergoing cardiac surgery. The study was funded by grants from the Burroughs Wellcome Fund and the US Food and Drug Administration.
According to press release from the ACC, the study is the largest to assess the effects of closing the left atrial appendage. The finding suggests that the approach may be a good option, particularly for patients with AF who are at high risk for stroke but cannot take or tolerate anticoagulant medications.
Dr. Friedman, who is a cardiology fellow at Duke Clinical Research Institute in Durham, North Carolina, commented in the ACC announcement, “There’s currently a wide variation in the use of this procedure at the time of cardiac surgery, largely due to the fact that there’s not good data on the safety or the efficacy of the procedure. While our study was not a randomized trial, it does demonstrate strong support for the benefits of closing the left atrial appendage at the time of cardiac surgery in patients with atrial fibrillation.”
The ACC stated that to assess the safety and efficacy of closing the left atrial appendage, the investigators analyzed the health records of 10,524 patients in the STS Adult Cardiac Surgery Database, a nationally representative data set that includes 90% of cardiac surgery centers in the United States. They extracted data for Medicare patients with AF who underwent coronary artery bypass grafting, aortic valve surgery, or mitral valve surgery in 2011 or 2012.
Approximately 37% of the patients had their left atrial appendage closed during their surgery. Of these, 1.6% were hospitalized for thromboembolism within 12 months, which is the study’s primary endpoint. Significantly fewer than the 2.5% of patients experiencing thromboembolism who did not have their left atrial appendage closed. Dr. Friedman noted that this translates to a 40% reduction in risk over 12 months and that this reduction would likely grow more impactful as it accumulates over time.
In addition, the investigators found that closing the left atrial appendage was associated with a 15% reduction in the rate of death and a 21% reduction in a composite of thromboembolism, hemorrhagic stroke, and death. There was no significant difference in the rate of hemorrhagic stroke, a type of stroke caused when a blood vessel in the brain ruptures. Dr. Friedman said the results suggest closing the left atrial appendage is safe and effective for AF patients undergoing cardiac surgery.
Dr. Friedman explained, “Intuitively, surgical left atrial appendage occlusion should work; however, there have been concerns that incomplete occlusion actually could lead to increased risk for thromboembolism because it could result in small communications between the appendage and the left atrium. The fact that we saw such a dramatic association between the procedure and a reduction in thromboembolism was reassuring that, at least in a more contemporary cohort of patients, left atrial appendage occlusion is able to be done in a much more effective way than initial reports had suggested may be the case.”
Dr. Friedman advised that further analysis revealed the greatest reduction in thromboembolism after left atrial appendage occlusion among patients who were not taking anticoagulant medications at discharge. There was no difference in thromboembolism rates for those who were taking anticoagulants at discharge. Whether left atrial appendage occlusion is effective enough to allow patients to safely stop taking anticoagulants is one potential area for future investigation.
He also stated that limitations of the study include that it is an observational analysis. A prospective, randomized controlled trial would provide more robust evidence to support clinical decision making. The study also was not able to compare different techniques used to close the left atrial appendage, another aspect that could be investigated in future studies, noted Dr. Friedman in the ACC announcement.