If you use the IU Video Bridge technology, UITS recommends holding off on upgrading to Office 2013. The Lync 2013 client cannot make video or audio calls to conferences on the IU Video Bridge (e.g. firstname.lastname@example.org) or directly to conference room systems.
UITS hopes to have a solution soon. In the meantime, if you do upgrade to 2013 but still need to participate in IU Video Bridge calls, you can request a Cisco Telepresence Movi account as a substitute.