The following is NLM's rationale for treatment of the publication
Europena Journal of Surgery (alias Acta Chirurgica Scandinavica):

When the publisher decided to change the title and publish only in
English, the editor called NLM and asked how that change would alter
its indexing entry in IM.  He said they also wanted to display a form
of the earlier title, Acta Chirurgica Scandinavica, to show continuity
with that title, but that the title would be European Journal of Surgery.
The Catalog Section advised him that the new serial would be indexed
under the title it was cataloged.  According to rule AACR2 1.1B8 if
there is a parallel title in multiple languages, the language of the
content is preferred.  When the first issue arrived, the chief source,
the cover, did indeed have two titles, Latin and English, and the
contents were in English.  However, other places within the publication
cited them with the Latin first in a way that could be interpreted as
a Latin title proper and an English subtitle.  The Catalog Section
contacted the editor.  He assured NLM that the editoral borad considered
the journal to have parallel titles, not title and subtitle.  There had
been some miscommunication with typists, printers, etc. but that the
Latin would be phased out and the title be displayed in English only.

This week the NLM Catalog Section also received a fax from Sweden
explaining the problem with the numbering of the supplements which
resulted from a change in distribution companies and printers.
Supplement 561 began the new title, but Supplement 562 which should
have been issued last year, had already been printed with the old
title.  NLM cataloged the new supplement with the English title
again using the cover as the chief source, according to LC RI for rule 12.OB1
which gives exceptions for title page substitutes.  It begins with 561; the
 ear
earlier title ends with no 562.  The numbering irrugularity is described in a
note.

If totally confused, contact Kevin McShane in the serial cataloging unit at
NLM --
Bill Willmering
Serial Records Section
NLM