My doctor told me that, absent any other complicating factors, between 5.0 and 5.5 is normally a bit of a "gray" area where a patient's own views should take precedence. The risk of a dissection in that range are still comparatively low, or as you first doctor said, not "emergent." It's once you hit 5.5 that the risk of dissection starts to go up exponentially. However, the fact that you had GCA does seem significant and would seem to raise your risk. Fundamentally, it's your choice. If you were younger, below 60 like me, then the surgery option might seem more compelling, but as you get older, the recovery from major surgery becomes more challenging, especially if you have any other health conditions. One comment: a variation between 4.8 (below surgical threshold) and 5.3 is pretty wide. I would think that the doctor would want the most precise measurement possible using a gated CT scan with contrast, if that has not already occurred.

Pattiej,
You probably have it covered with your Dr. Fischbein appointment. But just in case something changes that appointment, here is a recommendation that costs nothing. Heartvalvesurgery.com is Dr. Bavaria and Dr. Desai who are also major specialists in this area and have done a few YouTube films on this subject. The one thing that got to me is that they have done literally hundreds of these operations and said that a patient should look for a doctor who has done at least 100 per year, every year. Reason being, that any number under that means less experienced Doctors and Hospitals attending staff may not be familiar with emergencies that could pop up. Seems reasonable to me. Good luck.