My friend has dual U.S.-Swedish citizenship. It's crazy to think, but a few times now he's actually flown out to Sweden to have a medical procedure performed, because it's _cheaper_ to get an international round-trip ticket to Sweden then it would be to just have the procedure done in the U.S. (where he lives). And it's never been anything big; just outpatient type stuff.
The U.S. healthcare system _is_ totally out of control.