I really don't know, except that maybe the surgeon was estimating from the appearance of the tissue. There may be a characteristic appearance of these things, after varying lengths of time, that the surgeon can observe when the patient is opened up. That's only speculation on my part, but if your uncle did not have any kind of crisis with an increase in pain and symptoms two weeks before the surgery, then I don't know what else the surgeon could have been going by. Also, I assume the surgeon could have been off in his estimate, and maybe the final series of events did start at more like four weeks. Every patient is different, and so maybe the appearance of your uncle's aorta looked like a two week-old rupture when it was actually a four week-old rupture. Or maybe the aneurysm got big enough at four weeks that it started hurting because of its size, but the tissue didn't actually start tearing until some time after that. It's hard to tell, after the fact, what exactly happened.
Unfortunately, it's not rare for serious aortic problems to be overlooked or misdiagnosed until it's too late. An acquaintance of mine died of an abdominal aortic aneurysm less than a year ago. His doctors thought for several days that he was having a flare-up of his chronic back problems. They finally figured it out and admitted him to the hospital for surgery, but he died on the table. The aorta is the biggest blood vessel in the body, and when it ruptures, the bleeding is massive and fast. More common than a rupture is a partial tear, called a dissection, and even that is usually fatal. Your uncle's rupture may have started with a dissection, which can progress slowly. Again, I'm only speculating, but if he initially had a small dissection, and it only gradually progressed to a full rupture, that could explain why he was symptomatic for several weeks before he died. This kind of unexpected death is a terrible shock for the family. Again, I'm so sorry.
Thank you for your reply. The information you have provided has been very helpful in allowing us to understand what may have happened. It really was such an unfortunate situation. What I fail to understand is how the vascular surgeon was able to determine that the aneurysm had ruptured and clotted 2 weeks prior to the surgery. This is odd as my uncle had been experiencing symptoms (back pain, inability to eat) for 4 weeks prior to the surgery.
I can't give you percentages, but a ruptured aortic aneurism is a fatal situation in probably the majority of people who experience it, even if they undergo surgical treatment. It is just a very, very bad situation. The prospects of survival without surgery are pretty much nil, so the surgery was your uncle's only chance. Sometimes the initial tear is small, and it will clot, but the person still needs treatment. I assume that either the clot moved, which would have been sure to happen at some point, or possibly the tear in his aorta enlarged, or perhaps both. Any combination of those events would lead to massive internal bleeding or other life-threatening complications. Possibly the stroke was caused by a clot fragment that traveled through the circulatory system into his brain, so sometimes a clot is not even a good thing. Sometimes a person does live with a small tear in the aorta for a period of time, before the fatal event occurs. I'm very sorry for the loss of your uncle, but one thing the family should not feel bad about is the decision for him to undergo treatment. A ruptured aortic aneurysm is something that is very difficult to survive under any circumstances, but he definitely would not have survived it if he had not tried to have it repaired. He took the best opportunity he had. Please accept my condolences.