title: The importance of intraoperative selenium blood levels on organ dysfunction in patients undergoing off-pump cardiac surgery: a randomised controlled trial.
abstract: BACKGROUND
  Cardiac surgery is accompanied by an increase of oxidative stress, a significantly reduced antioxidant (AOX) capacity, postoperative inflammation, all of which may promote the development of organ dysfunction and an increase in mortality. Selenium is an essential co-factor of various antioxidant enzymes. We hypothesized a less pronounced decrease of circulating selenium levels in patients undergoing off-pump coronary artery bypass (OPCAB) surgery due to less intraoperative oxidative stress.
  
  
  METHODS
  In this prospective randomised, interventional trial, 40 patients scheduled for elective coronary artery bypass grafting were randomly assigned to undergo either on-pump or OPCAB-surgery, if both techniques were feasible for the single patient. Clinical data, myocardial damage assessed by myocard specific creatine kinase isoenzyme (CK-MB), circulating whole blood levels of selenium, oxidative stress assessed by asymmetric dimethylarginine (ADMA) levels, antioxidant capacity determined by glutathionperoxidase (GPx) levels and perioperative inflammation represented by interleukin-6 (IL-6) levels were measured at predefined perioperative time points.
  
  
  RESULTS
  At end of surgery, both groups showed a comparable decrease of circulating selenium concentrations. Likewise, levels of oxidative stress and IL-6 were comparable in both groups. Selenium levels correlated with antioxidant capacity (GPx: r = 0.720; p<0.001) and showed a negative correlation to myocardial damage (CK-MB: r =  -0.571, p<0.001). Low postoperative selenium levels had a high predictive value for the occurrence of any postoperative complication.
  
  
  CONCLUSIONS
  OPCAB surgery is not associated with less oxidative stress and a better preservation of the circulating selenium pool than on-pump surgery. Low postoperative selenium levels are predictive for the development of complications.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT01409057.
authors.affiliation: Department of Anaesthesiology, University Hospital of the RWTH Aachen, Aachen, Germany.
authors.forename: Ana
authors.initials: A
authors.lastname: Stevanovic
authors.affiliation: Department of Anaesthesiology, University Hospital of the RWTH Aachen, Aachen, Germany.
authors.forename: Mark
authors.initials: M
authors.lastname: Coburn
authors.affiliation: Department of Thoracic, Cardiac and Vascular Surgery, University Hospital, RWTH Aachen, Aachen, Germany.
authors.forename: Ares
authors.initials: A
authors.lastname: Menon
authors.affiliation: Department of Anaesthesiology, University Hospital of the RWTH Aachen, Aachen, Germany.
authors.forename: Rolf
authors.initials: R
authors.lastname: Rossaint
authors.affiliation: Kingston General Hospital, Kingston, Ontario, Canada.
authors.forename: Daren
authors.initials: D
authors.lastname: Heyland
authors.affiliation: Department of Anaesthesiology, University Hospital of the RWTH Aachen, Aachen, Germany.
authors.forename: Gereon
authors.initials: G
authors.lastname: Schälte
authors.affiliation: Department of Anaesthesiology, University Hospital of the RWTH Aachen, Aachen, Germany.
authors.forename: Thilo
authors.initials: T
authors.lastname: Werker
authors.affiliation: Institute of Physiological Chemistry, Centre for Physiological Medicine, Medical University of Graz, Graz, Austria; Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria.
authors.forename: Willibald
authors.initials: W
authors.lastname: Wonisch
authors.affiliation: Institute of Clinical Chemistry, Friedrich-Schiller University, Jena, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Kiehntopf
authors.affiliation: Department of Thoracic, Cardiac and Vascular Surgery, University Hospital, RWTH Aachen, Aachen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Goetzenich
authors.affiliation: Department of Anaesthesiology and Department of Cardiovascular Sciences, University Hospitals Leuven, KU Leuven, Belgium.
authors.forename: Steffen
authors.initials: S
authors.lastname: Rex
authors.affiliation: Department of Anaesthesiology, University Hospital of the RWTH Aachen, Aachen, Germany; Department of Thoracic, Cardiac and Vascular Surgery, University Hospital, RWTH Aachen, Aachen, Germany; Institute of Biochemistry and Molecular Cell Biology, RWTH Aachen University, Aachen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Stoppe
mesh_terms: D000368:Aged; D001120:Arginine / Q000031:analogs & derivatives / Q000097:blood; D015415:Biomarkers / Q000097:blood; D047549:Coronary Artery Bypass, Off-Pump / Q000009:adverse effects*; D052279:Creatine Kinase, MB Form / Q000097:blood; D005260:Female; D005979:Glutathione Peroxidase / Q000097:blood; D006801:Humans; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D011183:Postoperative Complications / Q000097:blood / Q000175:diagnosis; D011184:Postoperative Period; D011237:Predictive Value of Tests; D012643:Selenium / Q000097:blood*
chemical_list: D015415:Biomarkers; D015850:Interleukin-6; C018524:N,N-dimethylarginine; D001120:Arginine; D005979:Glutathione Peroxidase; D052279:Creatine Kinase, MB Form; D012643:Selenium