Gee, the first thing to ask, is how high is high? A modest elevation may not be too meaningful. Also, how are your other liver enzymes?
You are doing the right thing by following up with further tests, but until those are done, it's anyone's guess in regard to what this all means.
That said, I had elevations of AST and ALT enzymes (about 3 times the upper limit of normal). PSC was ruled out with an MRCP, and the assumption was non-alcoholic fatty liver disease (also associated with UC). Now my enzymes are normal. No particular treatment other than some weight loss and treatment of my underlying disease (pouchitis and enteropathic arthritis).