I asume you are referring to the aorta valve and not vessel. I have mitral valve regurgitation (moderate to severe) and have done some research on the best surgeons for valve operations. The Mayo clinic have very good surgeons and the valve surgeon has puplically stated the biggest problem he sees is that the patient waited too long. The problem can be the stenosis of the valve opening is narrower than normal and restricts blood flow with each heartbeat and the result is an enlarged left ventricle that will reduce conmtractility.
According to my research the very best surgeons can repair the valve rather than replace. I read that almost all valves can be repaired. If that be true, that would certainly reduce the risk factor. You may want to contact Mayo Clinic Rochester, Minn or the Cleveland Clinic. They have the very best surgeons and state-of-the art technology.
Thank you for your question, and if you have any further questions or comments you are welcome to respond. Take care,
Ken