My wife had a PFO that was only diagnosed when she was being evaluated for a double lung transplant. She was 70 at the time and had lived symptom-free all her life. Her PFO was repaired during the transplant procedure so is no longer an issue. From what I have been told, having a PFO increases the likelihood of having a TIA or a thrombosis but how much is not clear. There is a procedure available for closing the foramen using procedures similar to those used in cardiac catheterization. I'm not sure how widely available the procedure is but it is worth looking into. Were I in your shoes, I would be (doing what you are doing) researching the web and bugging the devil out of any medical advisor within reach. Good luck with the bugging and hope it all works out well for you.