Hi Marty. Welcome to this wonderful site. It seems there is suddenly quite a crop of people visiting surgeons for the first time (I'm one!) so there are several threads going regarding these meetings. Please wander through the site, use the search button if you have a specific area to investigate and then read, read, read!
I'm not sure, with your enlarged aorta, if you would have a choice between a tissue valve (bovine/cow or porcine/pig) and a mechanical one. This is the biggest controversy as there are pros and cons for each. You will definitely want his opinion.
Finding a surgeon who is experienced in the work that you need to have done is very important. You can ask them how many replacements they perform each year. Knowing the quality of your hospital is important. He should be willing to offer you statistics and information.
I know others will be along, those who've already gone through this and have more perspective than I have at this point.
Happy reading! Marguerite