Systematic review finds evidence is lacking for percutaneous LAA exclusion as an alternative to oral anticoagulation

A systematic review of the published literature found that there was no evidence to recommend percutaneous left atrial appendage (LAA) exclusion in patients with atrial fibrillation who are ineligible for anticoagulation.

The researchers also mentioned that LAA exclusion was not associated with increased risks during heart surgery. However, there was no evidence of benefit, either.

Lead researcher North Noleck, MD, MPH, of the VA Portland Healthcare System in Oregon, and colleagues published their results online in Circulation: Cardiovascular Quality and Outcomes on July 12.

Between 2.7 million and 6.1 million people in the U.S. have atrial fibrillation, which the researchers noted increases with age and is commonly associated with an increased risk of bleeding.

Until 2002, surgery was the only option for exclusion of the LAA. Since then, several devices have been developed to occlude the LAA percutaneously, including the PLAATO device (Appriva Medical), the Amplatzer device (St. Jude Medical), the Watchman device (Boston Scientific) and the Lariat suture delivery device (SentreHeart).

The researchers identified 20 primary studies and five systematic reviews that met their inclusion criteria by searching the Ovid MEDLINE, Embase, Cochrane and FDA databases from inception through Jan. 7, 2015. They included controlled trials that assessed the effectiveness of percutaneous LAA exclusion procedures and cohort studies with or without a control group. 

Among the studies were two randomized trials (PREVAIL and PROTECT-AF) that compared the Watchman device with warfarin therapy.

The FDA approved the Watchman device in March 2015 as an alternative to warfarin in high-risk patients with nonvalvular atrial fibrillation. In February, the Centers for Medicare & Medicaid Services (CMS) released its final national coverage determination for the Watchman, making the device available to certain Medicare and Medicaid patients.

In the PROTECT-AF study, there was no difference in the composite primary efficacy endpoint of ischemic/hemorrhagic stroke, cardiovascular/unexplained death and systemic embolism between patients receiving the Watchman device and those receiving warfarin. Although a subset of patients had a modest improvement in quality of life, the researchers noted that the absolute differences were small and the findings were subject to bias.

The PREVAIL study did not meet the target of noninferiority for the Watchman device, but the event rates were similar: 2.6 percent for the Watchman group and 2.2 percent for the warfarin group. Meanwhile, the composite of death, ischemic/hemorrhagic stroke and systemic embolism occurred in 5.2 percent of patients in the Watchman group and 2.9 percent of patients in the warfarin group.

Further, 10.6 percent of patients in the PROTECT-AF trial and 2.2 percent of patients in the PREVAIL trial had a safety event.

Although researchers said there serious periprocedural events reported in all devices, they did not find any comparative effectiveness data to assess the relative rates of serious safety events based on the device used. They also mentioned that no randomized controlled trial has examined deployment success, LAA exclusion achieved or health outcome benefits among the devices.

The researchers mentioned a few clinical situations in which percutaneous LAA exclusion may be beneficial, although they said the data was limited. They noted percutaneous LAA exclusion could be beneficial for patients who are unable to take oral anticoagulants, patients who may have substantial bleeding risk for oral anticoagulant therapy and patients who prefer the placement of an LAA exclusion device over long-term oral anticoagulant therapy.

“Overall, there is limited evidence that percutaneous LAA exclusion may be an effective alternative to [long-term] oral anticoagulation in selected patients who are closely followed and in whom procedural success is sustained,” the researchers wrote. “However, only one percutaneous device has been studied rigorously in trials, and percutaneous LAA exclusion has been associated with high rates of serious procedure-related harms in many studies. There is insufficient evidence to assess the benefits of surgical LAA exclusion. Although surgical LAA exclusion does not seem to be associated with a significant increase in harms over the heart surgery during which the procedures are typically performed, rates of procedural success may be low. Overall, there is insufficient evidence to support the routine use of surgical LAA exclusion to reduce stroke risk or future need for anticoagulant therapy. There are several ongoing studies that should add substantively to this body of evidence during the next several years.”