Hi
as you know that anticoagulation (can't abide 'blood thinners', its not paint and its not thinned) for a tissue valve is administered only for the first 3 - 6 months, and then without other circumstances (like for instance AtrialFib) is discontinued. This is because experience has shown that for this period clots can form.
I didn't see when your surgery was so I can't be sure if you're past that point of time. I would consider it a risk but a very minor risk. I've got a mechanical and I've been off anticoagulation for some days after a surgery and nothing happened. I got the impression that such was common.
If you consider it from a risk view (where everything is a nonzero risk) its a risk but a very minor risk. An example:
* cross a street blindfolded
Yes, its a risk but it depends on where and what time. NY in daylight, with 4 lanes of traffic is a higher risk than a tiny mid-western country town at 3am on a back street.
My view is that surgeons are *very* risk averse, and if he's willing to get his name on it then the risks will be low.
that's my thoughts.