I fear that as long as the hole remains un repaired, he will continue to have these issues. The poor blood flow due to the hole causes clotting, clots may cause strokes.
Perhaps his staying on aspirin the rest of his life will be all he needs, but I really would not feel comfortable if it were me. I'd go for repair to eliminate the cause.
I'm not sure if it's a RULE or not, but I'm guessing it's a big no-no to play games when you are on blood thinners. Aspirin isn't a prescribed blood thinner, but it's an anti-coagulant nonetheless and I'm not sure that they are allow to play if they are on them....
As for the hole in his heart, there isn't much research to suggest that it's a MAJOR issue. His stroke has been so-far deemed unrelated. About 20% of people have a small hole in their heart and 99% of those people have no symptoms.
I'm wondering if he has any other issues we haven't heard about like Atrial Fibrillation, which can cause blood clotting in the heart, and during intense exercise --- which we all know is something Letang does ALOT --- those clots can come loose and travel to the brain, causing a stroke.
There are too many factors to be honest. My father is the doctor in the family, not me, so I'm just spitballing with stuff I've picked up over the years, but since Kris has wanted to be open and honest about this condition to raise awareness, then I can only presume we've heard pretty much everything the doctor's know, and right now, they aren't linking it to his heart condition.