Surgical indications for an aortic anuerysm include: 1) the presence of symptoms (back, chest pain), 2) the rate of growth of the aneurysm (> 1 cm/year), or 3) the overall size of the aneurysm - in which typically 5 cm is the cutoff. However, there are certain conditions that change the indications including a history of Marfan's disease (4.5 cm), bicuspid aortic valve (4.5 cm). Non-invasive serial monitoring by echocardiogram is often recommended annually and often times every 6 months for larger aneursyms to watch for rate of growth and overall size. Below is a website from the Cleveland Clinic regarding this issue. If not already, I would recommend speaking to your cardiologist to ensure that there is not an indication for surgical repair based on your historical rate of growth, history of symptoms, and based on your height (see website).
http://my.clevelandclinic.org/heart/disorders/aorta_marfan/surgerythoracicaneurysm.aspx
Thank you for your answer. I have checked the link you gave me and learned about the ratio between maximum aortic diameter and body surface area. I was surprised to realize that according to this ratio I am at risk for dissection/rupture since I am 5,8ft and 132lbs with max. diam. of my root aneurysm 4,8cm. That gives me an aortic size index of 2.79 cm/m2. What is your opinion about this?