what were the top four most common drugs that followed during the same hospital visit for the patients who were given lt heart angiocardiogram during the previous year?
select t3.drug from ( select t2.drug, dense_rank() over ( order by count(*) desc ) as c1 from ( select admissions.subject_id, procedures_icd.charttime, admissions.hadm_id from procedures_icd join admissions on procedures_icd.hadm_id = admissions.hadm_id where procedures_icd.icd9_code = ( select d_icd_procedures.icd9_code from d_icd_procedures where d_icd_procedures.short_title = 'lt heart angiocardiogram' ) and datetime(procedures_icd.charttime,'start of year') = datetime(current_time,'start of year','-1 year') ) as t1 join ( select admissions.subject_id, prescriptions.drug, prescriptions.startdate, admissions.hadm_id from prescriptions join admissions on prescriptions.hadm_id = admissions.hadm_id where datetime(prescriptions.startdate,'start of year') = datetime(current_time,'start of year','-1 year') ) as t2 on t1.subject_id = t2.subject_id where t1.charttime < t2.startdate and t1.hadm_id = t2.hadm_id group by t2.drug ) as t3 where t3.c1 <= 4