title: Outcomes and long-term survival of coronary artery surgery: The controversial role of opium as risk marker.
abstract: OBJECTIVE
  To study survival in isolated coronary artery bypass graft (CABG) patients and to evaluate the impact of preoperative chronic opium consumption on long-term outcome.
  
  
  METHODS
  Cohort of 566 isolated CABG patients as Tehran Heart Center cardiac output measurement was conducted. Daily evaluation until discharge as well as 4- and 12-mo and 6.5-year follow-up information for survival status were fulfilled for all patients. Long-term 6.5-year overall and opium-stratified survival, adjusted survival curves based on opium consumption as well as possible predictors of all-cause mortality using multiple cox regression were determined by statistical analysis.
  
  
  RESULTS
  Six point five-year overall survival was 91.8%; 86.6% in opium consumers and 92.7% in non-opium consumers (P= 0.035). Patients with positive history of opium consumption significantly tended to have lower ejection fraction (EF), higher creatinine level and higher prevalence of myocardial infarction. Multiple predictors of all-cause mortality included age, body mass index, EF, diabetes mellitus and cerebrovascular accident. The hazard ratio (HR) of 2.09 for the risk of mortality in opium addicted patients with a borderlinePvalue (P= 0.052) was calculated in this model. Further adjustment with stratification based on smoking and opium addiction reduced the HR to 1.20 (P= 0.355).
  
  
  CONCLUSIONS
  Simultaneous impact of smoking as a confounding variable in most of the patients prevents from definitive judgment on the role of opium as an independent contributing factor in worse long-term survival of CABG patients in addition to advanced age, low EF, diabetes mellitus and cerebrovascular accident. Meanwhile, our findings do not confirm any cardio protective role for opium to improve outcome in coronary patients with the history of smoking. Further studies are needed to clarify pure effect of opium and warrant the aforementioned findings.
authors.affiliation: Mahdi Najafi, Department of Anesthesiology, Tehran Heart Center, Tehran University of Medical Sciences, Tehran 1411713138, Iran.
authors.forename: Mahdi
authors.initials: M
authors.lastname: Najafi
authors.affiliation: Mahdi Najafi, Department of Anesthesiology, Tehran Heart Center, Tehran University of Medical Sciences, Tehran 1411713138, Iran.
authors.forename: Leila
authors.initials: L
authors.lastname: Jahangiry
authors.affiliation: Mahdi Najafi, Department of Anesthesiology, Tehran Heart Center, Tehran University of Medical Sciences, Tehran 1411713138, Iran.
authors.forename: Seyedeh Hamideh
authors.initials: SH
authors.lastname: Mortazavi
authors.affiliation: Mahdi Najafi, Department of Anesthesiology, Tehran Heart Center, Tehran University of Medical Sciences, Tehran 1411713138, Iran.
authors.forename: Arash
authors.initials: A
authors.lastname: Jalali
authors.affiliation: Mahdi Najafi, Department of Anesthesiology, Tehran Heart Center, Tehran University of Medical Sciences, Tehran 1411713138, Iran.
authors.forename: Abbasali
authors.initials: A
authors.lastname: Karimi
authors.affiliation: Mahdi Najafi, Department of Anesthesiology, Tehran Heart Center, Tehran University of Medical Sciences, Tehran 1411713138, Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Bozorgi
keywords: Coronary artery bypass; Hazards models; Opium; Outcomes; Survival analysis