Converting old SQL Server outer join syntax
I just quickly grabbed your query and re-wrote it without looking at how you rewrote it.   

SELECT  DISTINCT  
   a_stmt.cyc_dte,   
   a_carr.carr_nm,   
   a_stmt.amt_du_ic  
 FROM  a_stmt 
    LEFT OUTER JOIN a_icc on a_stmt.ic_cntct_id = a_icc.ic_cntct_id   
    INNER JOIN a_carr on a_carr.acna = a_stmt.acna
    INNER JOIN s_dataccs on s_dataccs.acna = a_stmt.acna
WHERE (a_icc.usg_ind = 'S') and
(s_dataccs.user_id = @user_id)  and   
( ( a_stmt.acna = @acna ) or ( @acna = '' ) ) AND    
( ( a_stmt.juris_id = @juris_id ) or ( @juris_id = '' ) ) AND    
( a_stmt.jrnl_mo_yr = @jrnl_mo_yr ) AND  
( a_stmt.amt_du_ic &lt; 0 ) ;


It seems like you have the same thing as me (or at least basically), so I would say you are good.  Obviously if you could test that would be best but I feel comfortable that it is the same thing logically.