Hey Pelicle, yes they have done a TON of bloodwork as well as a TEE to check out my heart because they were initially really worried it could have been endocarditis. The results have been negative for any sort of infection.
The doctors here have been pretty thorough (neurologist, internal med, cardio & my heart surgeon). There are several more tests and blood cultures they ran that take 48 hrs so those results will come back today, so that could potentially shed more light as well.
They are also worried that an occurance of afib could have been the cause, which is why I'll be monitored for the next month as well.
A couple complicating factors are that I have been on birth control pills (which I will now need to stop taking), which can cause increased risk for clotting and I have family history of stroke and clotting (albeit my grandparents strokes and need for anticoagulants happened in their 80s not 20s!)
I know some people are put on Coumadin for the first 3-6 months after AVR, and I was not. I would imagine if many people are put on Coumadin after surgery that indicates an increased chance of clots in the months after surger even with a tissue valve...