A result obtained by A. Macintyre and J. Derakhshan states that the theory of a mixed characteristic henselian valued field with finite ramification, perfect residue field and whose value group is a Z-group, is model complete in the language of rings if the theory of the residue field is model complete in the language of rings. In this talk, we will see how this result can be generalized to mixed characteristic henselian valued fields with finite ramification, but with different value groups.