There appears to be a difference in procedural outcomes between women and men following implant of a left atrial appendage occlusion (LAAO) device, according to a letter issued by the Food and Drug Administration (FDA).

An analysis of real-world data from the National Cardiovascular Data Registry showed that among 49,357 patients undergoing LAAO procedures with the Watchman Left Atrial Appendage Closure device (41.3% women and 58.7% men), there was a significantly higher rate of adverse procedural events in women compared with men. This included an increased risk of any adverse event (6.3% vs 3.9%; P <.001), any major adverse event (4.1% vs 2.0%; P <.001), and hospital stay longer than 1 day (16.0% vs 11.6%; P <.001).

Specific procedural adverse events that occurred more often in women than men included pericardial effusion requiring percutaneous drainage (1.2% vs 0.5%), major bleeding (1.7% vs 0.8%), and death (0.3% vs 0.1%).

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The FDA is working with LAAO device manufacturers to determine what the cause may be for these differences. At this time, the Agency continues to believe that the benefits of these devices outweigh the potential risk. Clinicians should continue to monitor patients per the current standard of care; the risks and benefits should be discussed with patients as part of shared clinical decision-making.

Adverse events related to the use of LAAO devices should be reported to the FDA’s MedWatch program.


  1. Left atrial appendage occlusion (LAAO) devices potentially associated with procedural outcome differences between women and men – Letter to health care providers. September 27, 2021.
  2. Darden D, Duong T, Du C, et al. Sex differences in procedural outcomes among patients undergoing left atrial appendage occlusion: Insights from the NCDR LAAO registry. JAMA Cardiol. Published online August 11, 2021. doi:10.1001/jamacardio.2021.3021

This article originally appeared on MPR