My son also has a dilated aortic root. He is 15 years old. Some of the things his cardiologist has suggested he do differently are the following: Instead of going for a check up once a year go every six months. Don't pick up anything larger than 50 lbs. Stay away from strenuous activities. (Ex. heavy snow removal)
Hope this helps some.
Sorry, there are currently no proven methods for reducing or eliminating enlargement in smaller preclinical aneurysms. Given their relatively slow increase in diameter (typically <0.4 cm/year), some sureons wait until 5.5 cm. That would be an additional year, but it doesn't make sense to wait unless there is some compelling reason. Take care.