Hi Michelle,
The search for expertise is not an easy one, in spite of increasing information today.
I am wondering if you might have access to someone specializing in adult congenital heart conditions? They may be more aware of the implications of a quad leaflet valve and other potential complications with the aorta, etc..
Historically, the medical literature reflects the most information regarding the aorta has been published by surgeons. The aorta is not part of the heart, and there is no official, credentialed specialty in the thoracic aorta. However, surgeons have published the few text books ( I am aware of 2 or 3), and followed the statistics over the years. If a medical center has a thoracic aortic program or center, that could be a starting place for you in terms of your aorta as well as your valve.
Best wishes,
Arlyss