Hello @smithjdjc and welcome to Mayo Clinic Connect. In Connect we’re not medical professionals so we can’t diagnose health problems. However, we can share our own personal experiences and valuable insights to answer questions and offer encouragement.

I’m so sorry to hear you have Celiac Artery Compression (CAC). It can be a very serious condition if left untreated. A close friend of mine suffered for quite some with it before finally getting a diagnosis and help. Her symptoms were so similar to yours, so you have my deepest empathy. Her GI specialist, after diagnosing the condition referred her to a cardiovascular surgeon who handled her case from there. It’s discouraging your first surgery wasn’t effective, so seeking a second opinion at Mayo seems like a good course of action.

But first, let’s address your weight gain with CAC. You’re right in that weight loss is typical and can be severe with this condition because of the extreme pain associated with eating. But you’re gaining weight instead so I can understand your alarm.
You wondered if it could be an aneurysm. From my understanding it would be really uncommon to have a weight gain from an aneurysm.

Do you feel that you’re retaining water anywhere in your legs or ankles? Any puffiness in your fingers, that type of thing? Difficulty breathing?
Have you talked to your doctor about this change in your health?

For your peace of mind, it would really benefit you to be seen by your physician or the gastroenterologist/cardiologist? to help shed a light on what could be causing the weight gain. And also to obtain records and have your physician send a referral off to Mayo Clinic. Which Clinic did you have in mind?

Here is a link to the physicians referral page on Mayo Clinic’s website.
https://www.mayoclinic.org/medical-professionals/provider-relations/refer-patient?
_ga=2.207790103.408516767.1619350478-1072316699.1619350478

You can also self-refer but it is sometimes beneficial if your doctor provides the referral with medical records.
https://www.mayoclinic.org/appointment