I had open heart surgery to replace my auortic valve. now they are saying i have cystic medial necrosis. does this mean i have marfans?

Possibly: One of the features of Marfan's (a disorder of abnormal collagen tissue formation) is cystic medial necrosis, leading to abnormal tissue within the layers of the aorta which can lead to anneurysm formation of the aorta (a risk for regurgitation, rupture, and dissection). When such an aortic root measures more than 50 mm in diameter, these risks increase and require aortic root repair +/- avr if ai.

Not necessarily : Cmn is an inherited disorder that increases the chance if developing aneurysms and dissections of the aorta and other large vessels. It is a disease of what we call connective tissues. It is often found associated with marfan's but can also be seen in patients with ehlers-danlos syndrome and annuloaortic ectasia.