Enlarged Aorta - When does it become a concern?

I am a 47 year old male, with a bicuspid aortic heart valve, which appears to have stabilised over th epast cuple of years.  Regurgitation was an issue prior to that (approx 5% flow back).  Seeing my cardiologist last week, he advised me that I now have a new concern which could have stemmed from the valve, in that my Aorta has become enlarged over the past coupe of years, last May measuring 4.9cm, and last week 5.2cm.  He told me that surgery can be discussed when it reaches 5.5cm, and immediate surgery will occur when it gets to 6.0cm.  I have read elsewhere that it is recommended that immediate replacement occur when it gets to between 4.5 and 5.0cm.  Can someone advise what is current best practice for this condition and when the repair should take place?

[kenkeith]

Double post

[Between]

I definetly would get a second opinion on something like that. Have you seen a vascular surgeon?