How might history have been different if the Ottomans had lost the Battle of Constantinople in 1453?

Constantinople had not fallen to the Turks in 1453 it can be presumed that the city would have proven to be a thorn in their side (and Russia's) for centuries to come. The city controlled the access to the Mediterranean from the Black Sea and it would have been able to make both countries bend to its will simply to use the Dardanelles