Let's look up Ibuprofen up in a reliable source. We can read there that:
Increased risk of serious (sometimes fatal) cardiovascular thrombotic events (e.g., MI, stroke). Risk may occur early in treatment and may increase with duration of use. (See Cardiovascular Thrombotic Effects under Cautions.)
Contraindicated in the setting ...
Ibuprofen is a very-standard NSAID, and generally speaking it is a pretty safe drug when taken in an appropriate dose.
All medications have side-effects, Ibuprofen is not the exception. Now, usually these things are not an issue for healthy individuals. Mostly they can be a problem for people with pre-existing conditions.
Ibuprofen is not recommended for ...