Thank you for your detail response, I appreciate it.
I did spoke with the cardiologist at Cleveland clinic about the results. She was very confused herself and didn't have a good answer. She said that I need to follow up with my own cardiologist and have another CT scan done to compare this ECHO results, which I just have done CT scan in June showing 4.6CM (not 5.3).
My regular cardiologist said that ECHO is not reliable at all and especially where they measure Aorta size is very subjective and he would consider only CT as a benchmark and gold standard!
To peace myself, I have set-up another CT scan at the end of September to see what it shows.