20 + years as a medic. The last 5 dedicated to a heart center doing utra high risk transports. Don't sweat it. 75% of patients don't need anything past a stent (small chinese fingers looking device placed inside an artery, to hold it open). I've seen the practice vastly change in the last 10 years. I've watched as surgeries used to require big scars and long-durations. Now options are available to do surgeries, if needed at all, via an arthroscope.
Try not to worry yourself over the unknown. Ask a allot of questions. Become familar. Get a couple opinions after the results of the cath. Dr's expect this, its not an insult. Caths are child's play these days. The technology has advanced by leaps and bounds, all in the patients favor. If surgery is called for, keep calm and rational. Your composure will go a long way in aiding the patient in speedy recovery.
If results call for it or allow, seek out the best Heart Center in the state, or the best surgeon, practioner, or cardiologist. The nurses are usually great wealths of information.
Good Luck. Relax.