Case by case. We're used to it - certainly in the UK, we hear a lot of US from media, so it is fine. Usually we can work it out, even if e don't already know of it. But sometimes it needs to be explained.
Once I got drunk with some people from the US, and the next day I said to them "I was so pissed last night". They looked really worried, and asked why, what happened, what was wrong. It seems 'pissed' to me means 'drunk'. To the Americans it meant 'Angry'.
There are so many examples of this. Good luck!