is patient 24921's arterial bp [diastolic] ever less since 09/2101 than 73.0?
select count(*)>0 from chartevents where chartevents.icustay_id in ( select icustays.icustay_id from icustays where icustays.hadm_id in ( select admissions.hadm_id from admissions where admissions.subject_id = 24921 ) ) and chartevents.itemid in ( select d_items.itemid from d_items where d_items.label = 'arterial bp [diastolic]' and d_items.linksto = 'chartevents' ) and chartevents.valuenum < 73.0 and strftime('%y-%m',chartevents.charttime) >= '2101-09'