I posted this about my Dad's aortic aneyurism about two years ago. He has an aneyurism near the top of his aorta near where it curls back downward, so it's not in a spot where they can do minimally invasive endoscopic surgery. That means open heart surgery.
Basically, what they do in these situations is monitor the patient in kind of a risk / reward guessing game. The risk of dying during or very shortly after surgery is pretty high, however so is the risk of the aneyurism rupturing in which case the best modern medicine in the world won't save you.
Dad has gotten regular check-ups and chest imaging done since he was diagnosed in order to check the size of the aneyurism. As of his last checkup he is just under 5 cm. 5cm is generally the point at which the docs say you should really be considering going under the knife. In Dad's case however, he also has a bad heart valve, which he has had for years and the literature says puts him at 4.5mm for surgery.
Recently he had a consult with a surgeon at Upenn. We suspected the surgeon would tell him to have the surgery now. Instead it turns out the bad valve he has does not have any impact on his aneyurism, so they don't need to plop him on the table quite yet, and so we wait until summer.
Oh, he slipped up and told me that he was doing curls with 30 lb. dumbbells in each arm at the gym recently even though he knows he's not supposed to lift anything over 20-30 lbs. I suspect he routinely does way more than he's really supposed to at the gym, but who am I to talk? I'd probably do the same thing.
So instead of having open heart surgery this winter he's in Florida in 75 degree weather drinking beer* and playing golf. That's great news and he's a lucky bastard!
*if you can call Coors Light "beer"