I'm taking Xarelto and still am having mini strokes lasting only a few seconds due to having the genetic blood mutation MTHFR (it's homozygous as it comes from both of my parents). Tests have shown my doctor proof of the TIAs. I'm trying to find a folate level and any other possible preventative. I'm noticing memory problems and want to prevent further damage.
I see you're not far geographically from me. Have you tried going to any of the DMC (especially Huron Valley Sinai Hospital) physicians? Some are very, very good, and some are not the typical western medicine doctors who feel that medications are the first line of defense against everything.
Sounds like a hematologist might be helpful.
You might also try to find support groups for others with the MTHFR mutation.
Best of luck in finding some help!