title: Evidence for free-radical mediated injury during coronary artery bypass surgery.
abstract: Prolonged global ischemia followed by reperfusion during coronary artery bypass graft (CABG) surgery leads to a burst of oxygen free-radical generation and subsequent myocardial impairment. Blood samples were collected at different time periods from the right atrium of patients (n = 55) who underwent CABG surgery. Free-radical activity was measured by assays for thiobarbituric acid reactive species (TBARS), mainly malondialdehyde (MDA), at zero minute (before aortic cross-clamp), one minute and 10 minutes after declamping i.e. reperfusion. There was a significant increase (p < 0.001) in the level of MDA at one minute of reperfusion which continued to be elevated up to 10 minutes. This increase was significantly correlated with aortic cross-clamp time (r = 0.525, p < 0.05). The activity of CPK and CPK-MB was raised by two fold (p < 0.001) after release of the clamp. Plasma Troponin-T level was estimated in 10 patients during CABG surgery and a significant increase (p < 0.01) was observed at one minute as well as 10 minutes of reperfusion which correlated well (r = 0.81, p < 0.01) with the severity of ischemia. The concomitant rise in TBARS (marker of free-radical activity), CPK, CPK-MB and Troponin-T (indicators of myocardial damage) on reperfusion implies that there is free-radical mediated damage to the cardiac membrane during CABG surgery.
authors.affiliation: PD Hinduja National Hospital & Medical Research Centre, Bombay.
authors.forename: A
authors.initials: A
authors.lastname: Movahed
authors.forename: K G
authors.initials: KG
authors.lastname: Nair
authors.forename: T F
authors.initials: TF
authors.lastname: Ashavaid
authors.forename: P
authors.initials: P
authors.lastname: Kumar
mesh_terms: D015415:Biomarkers / Q000097:blood; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D003402:Creatine Kinase / Q000097:blood; D005260:Female; D006801:Humans; D007527:Isoenzymes; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000378:metabolism*; D015428:Myocardial Reperfusion Injury; D017382:Reactive Oxygen Species / Q000378:metabolism*; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D014336:Troponin / Q000097:blood; D020107:Troponin T
chemical_list: D015415:Biomarkers; D007527:Isoenzymes; D017382:Reactive Oxygen Species; D017392:Thiobarbituric Acid Reactive Substances; D014336:Troponin; D020107:Troponin T; D003402:Creatine Kinase