data have;
input subjid $ trtan base aval;
cards;
A1 1 12 14
A2 1 8 10
A3 1 12 9
B1 2 11 11
B2 2 10 13
B3 2 14 10
;
run;

data have_new;
  length subjid $200 trtan base_new aval_new 8 base aval 8;
  length highcap lowcap $200;
  set have;
  if base>aval then do;
    highcap='NONE';
    lowcap='FILLEDARROW';
    base_new=aval;
    aval_new=base;
  end;
  else do;
    highcap='FILLEDARROW';
    lowcap='NONE';
    base_new=base;
    aval_new=aval;
  end;
run;



proc template;
define statgraph highlowbar;
  begingraph;
    layout overlay /
      xaxisopts=(display=(line ticks tickvalues) griddisplay=on
        linearopts=(viewmin=0 viewmax=15))
      yaxisopts=(griddisplay=on display=(line ticks tickvalues));

      highlowplot y=SUBJID high=AVAL_NEW low=BASE_NEW /
        group=drug outlineattrs=(pattern=solid)
        type=bar barwidth=0.4 highcap=HIGHCAP lowcap=LOWCAP;
    endlayout;
  endgraph;
end;

ods graphics on / reset outputfmt=png imagename='highlowbar';

proc sgrender data=have_new template=highlowbar;
run;