ICD-9 to ICD-10 Dimension Model

I am curious if anyone has developed an ICD-9 to ICD-10 dimension model migration strategy. Since there are almost 10 times the number of members in ICD-10 and the method of building the hierarchies has changed, mapping is problematic. I am curious if anyone has developed an eloquent Dimensional strategy that they would be willing to share.

I'd be interested in knowing how you've used dimensional modeling to put ICD9 codes into a hierarchy? All in one flat dimensional table, or something more complex?

If you plan to report ICD-9 as ICD-9 and ICD-10 as ICD-10, then just add the ICD-10's to the same dimension an use the same bridge to hold the hierarchy.

If you plan to cross-reference them so ICD-9's roll up using the equivalent ICD-10, then again, put the ICD-10's in the same dimension but add additional attributes to hold the ICD-10 values. Populate the equivalent ICD-9 row with the ICD-10 attributes and build a second bridge table that connects ICD-9 child rows with the ICD-10 parents, as well as ICD-10 children with ICD-10 parents. Keep the original bridge if you wish to roll ICD-9's and ICD-10's separately without translation.