Large peridevice leaks after left atrial appendage occlusion (LAAO) are incredibly rare and not associated with a greater risk of adverse outcomes, according to new research published in JACC: Clinical Electrophysiology.[1] Smaller residual links are more common, however, and associated with a risk of thromboembolic and bleeding events.

The study’s authors explored data from more than 50,000 LAAO patients. All data came from the LAAO Registry, a collaboration between the American College of Cardiology (ACC), U.S. Food and Drug Administration (FDA), Society for Coronary Angiography and Interventions (SCAI), CMS and Boston Scientific. All procedures were performed from January 2016 to December 2019 using Boston Scientific’s Watchman 2.5 device. While 58.4% of patients were male, 93.1% were white.

Overall, 73.4% of patients had no residual leaks after the procedure. Small leaks (>5 mm) were seen in 25.8% of patients, and large leaks were seen in just 0.7% of patients.

The study’s primary endpoint — a composite of stroke, transient ischemic attack or systemic embolization — was seen in 3.49% of patients with small leaks, 3.13% of patients with large leaks and 2.98% of patients with no leaks. Major adverse events and major bleeding events were also more common among patients with small leaks than patients with no leaks or patients with large leaks.

The mortality rate, however, was higher among patients with large leaks (7.96%) than patients with no leaks (5.97%) or small leaks (6.41%).

“Our findings have important implications for procedural techniques and post-procedural management,” wrote lead author Mohamad Alkhouli, MD, an interventional cardiologist at Mayo Clinic in Rochester, Minnesota, and colleagues. “To mitigate the risk of future ischemic events, efforts should be made to achieve complete seal of the left atrial appendage when possible. This requires a comprehensive approach that includes adequate pre-procedural imaging and good understanding of the LAA anatomy, the pros and cons of the occluder device, and the mechanism of peridevice leak. Fortunately, second-generation devices are now available and have been associated with a lower incidence of both small and large leaks compared with first-generation devices.”