Should I wait when Blender isn't responding? By error I placed the angle of the smart uv unwrap to 1 and now Blender is not responding. I guess it calculates the uv. The problem is that I have a lot of unsaved changes on the mesh.

Should I wait it to come back to life or is there no point? Are there any possible solutions to save my unsaved data?
You can wait if you want, but it's probably going to take a long time before it will start responding. If you close it there is a way to recover you data; Blender autosaves your projects every 5 minutes, and you can change it if you want.

When you open Blender, go to 'File', then in the option, click 'Recover Auto save', wait for some time, and Blender will show all the autosaves it has taken according to the date. Click the unsaved projects, and save it when it opens.