I would say it probably depends on the country you are flying in. The only reference I can find so far, for the UK, out of the bible is:
4.2.3 Aircraft in the heavy vortex wake category will include the word 'HEAVY' immediately
following their callsign, on initial contact with an ATC Unit. The purpose of this call is
to confirm the aircraft type and/or vortex category is the same as that stated on the
flight progress strip.