Watchman compared to blood thinners

The Watchman is a small mesh 'thimble' implanted in the entrance to a left atrial appendage (LAA). One side does not fit all, and this means some people are not good candidates for a Watchman due to the natural variation in the length and shape of LAAs between patients.

Once installed, the idea is that the mesh becomes endothelialized over several months, and ideally the net outcome is a sealed LAA. This means nothing can leak out of it, and this will be determined in a trans-esophageal echocardiogram reading at about the six month mark after insertion/implantation. If it is leak-free, then the risk of a clot emerging from the LAA and traveling to other organs and causing a blockage or a stroke (in the brain) is reduced to near-zero and you can safely cease taking a DOAC like apixaban or rivaroxaban.

Cons: the Watchman doesn't always seal off the LAA completely, or it has been known, especially more recently now that many Watchmen have been installed for a number of year, that patients are getting checkups that show they have begun to leak again, years later. If they never seal properly, or begin to show unmistakable signs of new leaking, you now have some defined risk of a clot issuing from that appendage.

As I alluded to earlier, not all hearts can be fitted with a Watchman.

Pros: If they seal, then you can stop the expense and the risks of taking a DOAC. Risks would mean bleeding unusual amounts when cut, contused, when bruising, or during a severe accident. No DOAC = no risk of severe bleeds.

Note that there are other ways to seal off the LAA. There's the 'Mitra-clip' and the MAZE procedure variants.