instruction: when is the last time that patient 42396 has received a venous cath nec until 4 years ago?
response: SELECT procedures_icd.charttime FROM procedures_icd WHERE procedures_icd.icd9_code = (SELECT d_icd_procedures.icd9_code FROM d_icd_procedures WHERE d_icd_procedures.short_title = 'venous cath nec') AND procedures_icd.hadm_id IN (SELECT admissions.hadm_id FROM admissions WHERE admissions.subject_id = 42396) AND DATETIME(procedures_icd.charttime) <= DATETIME(CURRENT_TIME(), '-4 year') ORDER BY procedures_icd.charttime DESC LIMIT 1