Anticoagulation therapy after DS?

Hello, It's been a long while since I've been back on this forum.

I have afib and the older I've gotten, the worse it is. Now comes the time I need to start anticoagulation therapy. My doc prescribed Pradaxa, but the pharmacy says that's a no go for people with Bariatric surgery. I asked her if she was familiar with the DS procedure and if it was a factor in whether or not Pradaxa can be used. She did not know. I'm wondering if anyone here might have any information. Or some kind of online medical reference for this.

I cannot ask my surgeon as he retired in 2010. My surgery was in 2008.

Thank you in advance.