What is considered a fast growing ascending aortic aneurysm?

Hi, i dissected my aorta ascending and decending. The ascending was repaired emergency.
My decending on the other hand, is being medically managed.
I have 6 aneurysmal spots. Most of them are at 4 cm. I just saw my cardiothoracic surgeon says he is not worried, that everything is stable. (Even though I dissected in 2012 and feel like any day I could die) that he's not worried about me getting my hip replaced.
As far as as fast growing aneurysms I've always been told that a 1/2 cm in 6 months or 1 cm in a year. Is reason enough.
However, I've found that it's really up to your doctor's belief systems. You may have to fight for it.
Also, low dose ct may not have caught it because there's no contrast given.
They usually use CTA or ct angiography with a lot of contrast.
Good luck, God bless

Firt of all, there is "magic nbr for surgery". There are so many factors to consider beside the size of the aneurysm alone. Such as: height of person, family history of aneurysm, hyperflexibility syndromes, rate of aneurysm growth. I am 5.5 ascending aneurysm and have not had surgery. Am followed by Aortic Cardiothoracic Specialist at major medical center with a CT with contrast and echocardiogram performed annually and CT w/o contrast performed locally.

I'm 70, 6'1" and 180 lbs. I'm at 4.5cm. My surgeon said 5.5cm was the max and might do the surgery after 5.0cm as my father had an AAA (not a TAA). I agree that height, weight, etc. all are considered. However, 5.5cm is the tipping point from everything I've read, heard and watched. You might consider a 2nd opinion.