adding a left function in there works for me. Since there is always one single quote at the end I can leave it hard coded.
Declare @TestData varchar(29)
Set @TestData = (SELECT DISTINCT(PRIMARYKEY) FROM vAUDITTableChanges WHERE PRIMARYKEY = ("iFuturePriceID=N'4194582'"))
Select left(
Substring(@TestData, patindex('%[0-9]%', @TestData), Len(@TestData)),
len(Substring(@TestData, patindex('%[0-9]%', @TestData), Len(@TestData)))-1)