Four years out you're at very little risk, but the question of whether you need to stop the aspirin is still debated, as you've discovered. Personally, I think stopping the aspirin is such low risk that I would do so. I'm also four years out from a Watchman but I'm on a half-dose of Eliquis instead of aspirin. When I asked about stopping the Eliquis for hernia repair surgery just months after it was implanted, the answer was go right ahead and just stop. There's actually very little (if any) evidence that either of us needs to be on anything.