This sucks, but don’t sweat the cardiac cath. My 80 year old mother had one done this fall. It was a breeze.   Light sedation, three hours tops.  Two balloons and a stent and instantly feeling better afterwards.  Went from 95% blockage to 30%.    
Make sure you take the meds, though.  Without them the blockage can return quickly, especially with the coarse texture of a stent.  One of the meds keeps it wide open.  Another one is likely to make you feel colder than normal, but in her case it makes her hot all the time.