There is absolutely positively no reason, from an aviation standpoint, you cannot fly on a commercial aircraft.
The only issue is that you would be away from medical aid, if you had a problem requiring emergency intervention.
Hi Jenny, I realize this was a long time ago. But I too am in that situation where I have a 1.9 cm splenic aneurysm and want to go to Cuba. My doctor does not consider flying to cause a rupture but while on vacation you can be far away from a vascular surgeon if it should rupture. I am curious what did you end up doing?