Well, I've got an opinion also, but a slightly different one this time, and with limited evidence of sorts:
My surgeon touched on this topic when discussing stroke risk with prosthetic valves. He said that my native BAV (which was moderate to severe stenotic) actually posed a slight stroke risk, although very low, a fraction (1/5) of a percent. Now, since he was about to replace it, I didn't much care at the time, so didn't grill him further on the matter. But I was curious about it later, and since it did seem to make reasonable sense that it might be slightly higher than non BAV folks, I tried to research a little further. I found several limited study (20 patients or less) reports that linked BAV to stroke, but if memory serves, all were in the presence of moderate to severe calcification. Further, these were not official studies, these were patients who had stroke events, that were subsequently analyzed because they also had BAV and no other contributing factors. Now, with that said, the analyses did seem reasonable and appropriate and not completely out of left field (like saying that BAV causes diabetes because in a case study of 1 (me), it happened), and if/when I have time (admittedly a struggle of late), I can try and track them down.
Of course, back to the point on evidence, any thorough study establishing evidence of stroke risk in a given patient group usually involves a major intervention. In other words, when a large group of patients are having their valves replaced as one example, or taking an anticoagulant for A-Fib as another, it makes perfect sense to find out what everyone wants to know - is the intervention successful and what are the risks of things like stroke. However, if normally functioning BAV patients are walking around with at worst a fraction of a percent chance of stroke that perhaps happens only in the presence of valve deterioration (when the valve would be replaced anyway), there just doesn't seem to me to be much cause to put together a comprehensive study, particularly when there aren't any sponsoring entities (valve manufacturers, drug companies, etc) with a stake in the results.
So, who knows for sure. My surgeon may just be right, or maybe not. Maybe I was at a higher risk of stroke than the other non-BAV 35 year olds out there. But even if true, there are many causes of stroke, and having a BAV (particularly a non-failing one) would seem to be pretty low on the list of risk factors compared to some of the others (elderly, smoker, etc). So Dominic, sorry for such a roundabout answer to your very basic question, but I would think that as your situation currently exists (8 months out, valve in good shape, otherwise good health), your stroke risk is either equal to your non-BAV clone, or perhaps, just maybe, fractionally higher. Big picture, not worth worrying about.
Everyone else covered heart attacks and post-surgery impact, I agree with the above. As for your aneurysm graft, your native tissue overgrows it, supposedly the blood in your aorta doesn't even "know" it's there after awhile.
Dominic - Since your procedure is somewhat unique (aneurysm graft only - valve sparing), I'm curious, what post-surgery medications are/were you on? For instance, some tissue valve recipients are given Warfarin for 3 months, some are given just the long term Aspirin 81. I've never really thought about what might be done for an aneurysm graft with no valve? That may inform relative to stroke risk.