I have a PFO and had a small stroke last June. I'm not a doctor, but I've done a lot of research and talked to a lot of doctors.
The following article will help get you started. It is well written.
There is good evidence that the occurence of both a PFO and ASA significantly increases the risk of an embolic (clotted restriction) stroke.
One treatment option is Coumadin, which is a blood platelet anti=-clumping medicine. Another is a plug for the septal hole, called an occluder device, which is deployed with a catheter, through a leg vein. Occulders can be used for PFOs. The safety record for deployment is VERY high. The long-term data on safety is not available. Biggest risk is the device wearing a hole (erosion) in the heart wall, which actually grows around the device and covers it up.
There is a new device, awaiting FDA approval which significantly lowers the risk of erosion. It is the CardiA Intrasept. Well worth the wait, if you haven't had a stroke yet, I think. I don't know if your Atrial Septal Aneurism (ASA) preculdes the use of an occluder or not. If it does, the other option besides preventative medication may actually be open heart surgery.
BUT... your doctors will likely suggest preventative medication unless you've had two strokes already. Problem is, there are concerns about long-term use of Coumadin. I know this sounds pretty heavy. But if you get on Coumadin, you've probably reduced your risk immediately and can then take some time to determine if you want other protection (surgery or occluder).
Good luck. And OR COURSE, I am not a doctor and don't presume that what I'm sharing is perfectly accurate. It is my best understanding of the issues.
AND... death is inevitable. Suffering is not. Joy is not. We get to CHOOSE if we want joy and living fully in every moment. Live fully, with gratitude.