instruction: when did patient 011-59493 receive valve replacement or repair - emergent for the first time since 4 years ago?
response: SELECT treatment.treatmenttime FROM treatment WHERE treatment.patientunitstayid IN (SELECT patient.patientunitstayid FROM patient WHERE patient.patienthealthsystemstayid IN (SELECT patient.patienthealthsystemstayid FROM patient WHERE patient.uniquepid = '011-59493')) AND treatment.treatmentname = 'valve replacement or repair - emergent' AND DATETIME(treatment.treatmenttime) >= DATETIME(CURRENT_TIME(), '-4 year') ORDER BY treatment.treatmenttime LIMIT 1