In recent years some authors have shown a correlation between increased post operative troponin and increased 30 day mortality in patients with kidney disease that mirrors the known correlation in those with normal renal function. In patients undergoing non cardiac surgery, Walsh et al demonstrated a 4 to 6 fold increased risk of death associated with elevated post operative troponin in patients with reduced (\<60 ml/min, but \>30ml/min) preoperative estimated glomerular filtration rate (eGFR). A second, more recent study by Liem et al, also found post operative troponin elevations were associated with higher morbidity and mortality risk in patients with chronic kidney disease undergoing non cardiac surgery. Investigators aim to build upon the findings of these authors by examining the relationship between pre operative eGFR, post operative troponin and risk of post operative cardiac events in patients undergoing non cardiac surgery at St Paul's hospital. Investigators will conduct a retrospective chart review of electronic records for all patients undergoing non cardiac, inpatient surgery at St Paul's Hospital from June 1, 2020 to December 31, 2021). Investigators will include all patients for whom preoperative eGFR values are available, and patients on chronic dialysis. Patients are to be stratified by preoperative eGFR and primary outcomes compared between patients with normal vs abnormal preoperative eGFR. Primary outcomes to be reviewed are myocardial injury after non cardiac surgery (MINS) and troponin elevations.
