title: Myocardial lactate production is not involved in the ischemic preconditioning mechanism in coronary artery bypass graft surgery patients.
abstract: OBJECTIVE
  To study the relationship between ischemic preconditioning (IP) and lactate production and their impact on coronary artery bypass graft surgery patients.
  
  
  METHODS
  Prospective, randomized, controlled study.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  Eighty 3-vessel disease coronary artery bypass graft surgery patients with stable and unstable angina pectoris.
  
  
  METHODS
  The IP patients were preconditioned with 2 periods of 2-minute ischemia followed by 3-minute reperfusion before aortic cross-clamping.
  
  
  RESULTS
  The cardiac index (CI) after surgery was significantly higher in the IP group than in controls among stable patients (p = 0.013). IP was not effective in CI recovery in unstable patients. The baseline values of lactate production were 11.6%, 20.3%, -7.0%, and -2.9% in stable IP, stable control, unstable IP, and unstable control patients. Compared with baseline, lactate production increased significantly after the IP protocol (39.0% and 47.5% in the stable and unstable patients), and operation (47.5%, 31.7%, 35.4%, and 35.6% in stable IP, stable control, unstable IP, and unstable control patients) but not after 10 minutes of cardiopulmonary bypass (29.7% and 19.0% in the stable and unstable patients). There were no differences among the groups in lactate production after the operation. Lactate production after the IP protocol was negatively associated with CI recovery after surgery in the IP patients (p = 0.026).
  
  
  CONCLUSIONS
  The IP effects do not include modulation of lactate production. IP induces lactate production, but it seems not to be involved in the triggering process.
authors.affiliation: Division of Cardiac Surgery, Department of Anesthesiology and Intensive Care, Tampere University Hospital, Tampere, Finland.
authors.forename: Z K
authors.initials: ZK
authors.lastname: Wu
authors.forename: E
authors.initials: E
authors.lastname: Pehkonen
authors.forename: J
authors.initials: J
authors.lastname: Laurikka
authors.forename: L
authors.initials: L
authors.lastname: Kaukinen
authors.forename: E L
authors.initials: EL
authors.lastname: Honkonen
authors.forename: S
authors.initials: S
authors.lastname: Kaukinen
authors.forename: M R
authors.initials: MR
authors.lastname: Tarkka
mesh_terms: D000368:Aged; D000787:Angina Pectoris / Q000378:metabolism / Q000503:physiopathology / Q000601:surgery; D000789:Angina, Unstable / Q000378:metabolism / Q000503:physiopathology / Q000601:surgery; D002302:Cardiac Output; D002315:Cardiopulmonary Bypass; D001026:Coronary Artery Bypass; D003402:Creatine Kinase / Q000097:blood; D052279:Creatine Kinase, MB Form; D005260:Female; D006439:Hemodynamics; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial; D007527:Isoenzymes / Q000097:blood; D019344:Lactic Acid / Q000096:biosynthesis*; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D011446:Prospective Studies
chemical_list: D007527:Isoenzymes; D019344:Lactic Acid; D003402:Creatine Kinase; D052279:Creatine Kinase, MB Form