The Case Against Watchman for Stroke Prevention
Unless new data emerges, percutaneous closure of the left atrial appendage may become one of cardiology's biggest errors.
The procedure to place a plug in the left atrial appendage has gained traction in both the US and Europe. See this image from a recent US registry study.
The idea of this procedure is that the appendage in the left atrium is an area where clots can form and then break off and cause stroke. Plugging that area could reduce stroke.
But…readers of Stop and Think know that plausibility is not enough in medicine. You have to show that a procedure actually works. For appendage closure this means reducing stroke and bleeding without undo procedural complications.
In the lecture below I lay out the case against this procedure. The data are clear.
Recall that appendage closure is a preventive procedure for something that may or may not happen in the future:
Occluding the appendage isn’t easy: the appendage varies quite a bit in size and shape; the plug is a foreign body left in the left atrium (arterial side of the circulation), and the appendage is thin-walled, making perforation a common complication.
Six major points form the case against this procedure:
Data from the two pivotal regulatory trials (Watchman vs Warfarin) do not convince me. There were higher rates of ischemic stroke in the Watchman arm.
PROTECT and PREVAIL found no difference in major bleeding (if you count bleeding surrounding the procedure).
Percutaneous closure requires anti-platelet therapy and at least two studies find bleeding rates on anti-platelets are not much different from anticoagulants.
A foreign body in the heart can act as a nidus for clot formation. Device-related thrombus has been reported—and can occur many months after implant.
The procedure to implant this device has a major complication rate ranging from 3-9%. So even if there were future benefits (there aren’t), patients start the gamble with a significant upfront risk of harm.
There is dubious pathophysiological basis for this procedure. Recall that stroke is a systemic disease and LAA appendage closure is a focal solution.
Some may say, come on, John, you well know that procedures and devices improve over time.
That is true, but new data, including a report on the new Watchman (Flx), have not been reassuring. (See lecture.)
Below is a lecture that I have given nearly a dozen times on four continents. I gave a shorter version of it at the Heart Rhythm Society meeting this July in Boston.
I don’t know how you can look at this data and think this is a wise thing to do. I am happy to entertain counter points in the comments.
Also know that this argument has been peer-reviewed and published in the Heart Rhythm journal.