Queen carried in pretentiously refined vessel (6)
I believe the answer is:
artery
'vessel' is the definition.
(artery is a kind of vessel)
'queen carried in pretentiously refined' is the wordplay.
'queen' becomes 'ER' (abbreviation for Elizabeth Regina).
'carried in' indicates putting letters inside.
'pretentiously refined' becomes 'arty'.
'er' going into 'arty' is 'ARTERY'.
(Other definitions for artery that I've seen before include "bloody path" , "Major blood vessel or road" , "blood line" , "Major traffic route" , "vital route" .)