I wrote a macro to do something similar. I wanted to check a table's load status and, if it is unloaded, fire a stored procedure that loads it. It's for reloading critical tables after a reboot, but you could adapt it for your needs. It uses the _T_TABLEMEMORY set in the LASR library.
Instead of checking a specific table you will want to filter down the loadedtables dataset and then iterate through the rows to fire your PROC CONTENTS.
data loadedtables;
set VALIBLA._T_TABLEMEMORY;
run;
%macro ifunloaded(tablename, thescript);
proc sql noprint;
select count(*) into :OBSCOUNT from loadedtables where tablename = upper(&tablename) and uncompressedsize > 0;
%if &OBscount = 0 %then %do;
%put "&tablename is unloaded, we need to reload it";
proc stp program=&thescript;
run;
put "Table &tablename was unloaded and reload was attempted.";
%end;
%else %do;
%put "&tablename is already loaded, leave it alone";
%end;
%mend ifunloaded
