title: Are intraoperative precursor events associated with postoperative major adverse events?
abstract: OBJECTIVE
  Precursor events are undesirable events that can lead to a subsequent adverse event and have been associated with postoperative mortality. The purpose of the present study was to determine whether precursor events are associated with a composite endpoint of major adverse cardiac events (MACE) (death, acute renal failure, stroke, infection) in a low- to medium-risk coronary artery bypass grafting, valve, and valve plus coronary artery bypass grafting population. These events might be targets for strategies aimed at quality improvement.
  
  
  METHODS
  The present study was a retrospective cohort design performed at the Queen Elizabeth Health Science Centre. Low- to medium-risk patients who had experienced postoperative MACE were matched 1:1 with patients who had not experienced postoperative MACE. The operative notes, for both groups, were scored by 5 surgeons to determine the frequency of 4 precursor events: bleeding, difficulty weaning from cardiopulmonary bypass, repair or regrafting, and incomplete revascularization or repair. A univariate comparison of ≥1 precursor events in the matched groups was performed.
  
  
  RESULTS
  A total of 311 MACE patients (98.4%) were matched. The primary outcome occurred more frequently in the MACE group than in the non-MACE group (33% vs 24%; P = .015). The incidence of the individual events of bleeding and difficulty weaning from cardiopulmonary bypass was significantly higher in the MACE group. Those patients with a precursor event in the absence of MACE also appeared to have a greater prevalence of other important postoperative outcomes.
  
  
  CONCLUSIONS
  Patients undergoing cardiac surgery who are exposed to intraoperative precursor events were more likely to experience a postoperative MACE. Quality improvement techniques aimed at mitigating the consequences of precursor events might improve the surgical outcomes for cardiac surgical patients.
authors.affiliation: Division of Cardiac Surgery, Dallhousie University, Halifax, Nova Scotia, Canada; Department of Community Health and Epidemiology, Dallhousie University, Halifax, Nova Scotia, Canada. Electronic address: cherman@dal.ca.
authors.forename: Christine R
authors.initials: CR
authors.lastname: Herman
authors.affiliation: Division of Cardiac Surgery, Dallhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Légaré
authors.affiliation: Department of Community Health and Epidemiology, Dallhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Adrian
authors.initials: A
authors.lastname: Levy
authors.affiliation: Division of Cardiac Surgery, Dallhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Karen J
authors.initials: KJ
authors.lastname: Buth
authors.affiliation: Division of Cardiac Surgery, Dallhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Roger
authors.initials: R
authors.lastname: Baskett
mesh_terms: D000368:Aged; D016063:Blood Loss, Surgical / Q000401:mortality; D002315:Cardiopulmonary Bypass; D001026:Coronary Artery Bypass / Q000009:adverse effects* / Q000401:mortality; D005260:Female; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects* / Q000401:mortality; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009674:Nova Scotia / Q000453:epidemiology; D011183:Postoperative Complications / Q000453:epidemiology* / Q000401:mortality / Q000601:surgery; D015995:Prevalence; D058996:Quality Improvement; D019984:Quality Indicators, Health Care; D012042:Registries; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome