Air Embolism Deaths Tied to Watchman LAA Closure Device Access Systems

 More special care is needed when using the Watchman access systems used to deliver transcatheter left atrial appendage (LAA) closure devices due to a risk for air embolisms, according to an FDA alert

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Instructions for use have been updated for Boston Scientific's various access systems -- marketed as Watchman TruSeal, FXD, FXD Curve, TruSteer -- all used to provide vascular and transseptal access for Watchman FLX LAA occluders (the second generationopens in a new tab or window after the original Watchman).

Boston Scientific is warning users that patients under deep or conscious sedation, when procedures are performed without positive pressure-controlled ventilation, are at increased risk for negative left atrial pressures, which in turn increase the risk of air going through the hemostasis valve and potentially may result in air embolism. The risk is most notable in patients with pre-existing low left atrial pressure, hypovolemia, and partial upper airway collapse.

An investigation found that these air embolisms have led to severe events such as arrhythmia, hemodynamic collapse, stroke, and other end-organ failure caused by ischemia.

As of July 30, there have been 120 serious injuries and 17 deaths associated with this issue, the manufacturer reported.

Watchman LAA therapy has a rocky regulatory history, but nevertheless, the FDA approved the original in 2015opens in a new tab or window for stroke prevention in people with atrial fibrillation.

Updated instructions now state that going forward, to reduce the chances of air embolism, care should be taken that patients put under deep or conscious sedation are not hypovolemic.

Additionally, device exchanges with the Watchman access sheath valve should occur below the level of the heart or under fluid during insertion. To minimize vacuum, devices should be withdrawn slowly until near the valve, then exchanges made during expiration.

Not addressed in the safety communication were concerns of device-related thrombusopens in a new tab or window that have separately arisen from the Watchman reportsopens in a new tab or window.

https://www.medpagetoday.com/cardiology/interventionalcardiology/116865