title: Does normothermic normokalemic simultaneous antegrade/retrograde perfusion improve myocardial oxygenation and energy metabolism for hypertrophied hearts?
abstract: BACKGROUND
  Beating-heart valve surgery appears to be a promising technique for protection of hypertrophied hearts. Normothermic normokalemic simultaneous antegrade/retrograde perfusion (NNSP) may improve myocardial perfusion. However, its effects on myocardial oxygenation and energy metabolism remain unclear. The present study was to determine whether NNSP improved myocardial oxygenation and energy metabolism of hypertrophied hearts relative to normothermic normokalemic antegrade perfusion (NNAP).
  
  
  METHODS
  Twelve hypertrophied pig hearts underwent a protocol consisting of three 20-minute perfusion episodes (10 minutes NNAP and 10 minutes NNSP in a random order) with each conducted at a different blood flow in the left anterior descending coronary artery (LAD [100%, 50%, and 20% of its initial control]). Myocardial oxygenation was assessed using near-infrared spectroscopic imaging. Myocardial energy metabolism was monitored using localized phosphorus-31 magnetic resonance spectroscopy.
  
  
  RESULTS
  With 100% LAD flow, both NNAP and NNSP maintained myocardial oxygenation, adenosine triphosphate, phosphocreatine, and inorganic phosphate at normal levels. When LAD flow was reduced to 50% of its control level, NNSP resulted in a small but significant decrease in myocardial oxygenation and phosphocreatine, whereas those measurements did not change significantly during NNAP. With LAD flow further reduced to 20% of its control level, both NNAP and NNSP caused a substantial decrease in myocardial oxygenation, adenosine triphosphate, and phosphocreatine with an increase in inorganic phosphate. However, the changes were significantly greater during NNSP than during NNAP.
  
  
  CONCLUSIONS
  Normothermic normokalemic simultaneous antegrade/retrograde perfusion did not improve, but slightly impaired myocardial oxygenation and energy metabolism of beating hypertrophied hearts relative to NNAP. Therefore, NNSP for protection of beating hypertrophied hearts during valve surgery should be used with extra caution.
authors.affiliation: Institute for Biodiagnostics, National Research Council, Winnipeg, Manitoba, Canada.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Hongyu
authors.initials: H
authors.lastname: Liu
authors.forename: Tomas A
authors.initials: TA
authors.lastname: Salerno
authors.forename: Bo
authors.initials: B
authors.lastname: Xiang
authors.forename: Gang
authors.initials: G
authors.lastname: Li
authors.forename: Marco
authors.initials: M
authors.lastname: Gruwel
authors.forename: Michael
authors.initials: M
authors.lastname: Jackson
authors.forename: Darren
authors.initials: D
authors.lastname: Manley
authors.forename: Boguslaw
authors.initials: B
authors.lastname: Tomanek
authors.forename: Roxanne
authors.initials: R
authors.lastname: Deslauriers
authors.forename: Ganghong
authors.initials: G
authors.lastname: Tian
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004734:Energy Metabolism; D017379:Hypertrophy, Left Ventricular / Q000378:metabolism / Q000503:physiopathology*; D009206:Myocardium / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D010477:Perfusion / Q000379:methods*; D013552:Swine
chemical_list: D010100:Oxygen