As much as I know it is usually terated surgically. They insert a stent(i am not sue about spelling) into the aorta, so the wall is strenghtend. This stent is kind off made out of metall or plastic wires that are criscrossed ogether into a mesh that expand into a suportive structure in the aorta.
I am not sure about pharmacological treatment, but I belive that in early phases there is some help with drugs.
Jauzi

My husband had this surgery in june and it went well. It needs to be done asap as is really dangerous. A dacron stint is placed inside the aorta to protect it from rupture. Don't delay on this surgery! My husbands was at 5 cm and you don't want it to get any larger than this. Remember that at 10 cm, you deliver a baby.