Systemic free radical activation is a major event involved in myocardial oxidative stress related to cardiopulmonary bypass.
BACKGROUND
Cardiopulmonary bypass (CPB) can induce deleterious effects that could be triggered in part by radical oxygen species; however, their involvement in the course of surgery has been elusive. The aim of this study was to evaluate the time course and origin of radical oxygen species release, myocardial or not, in patients undergoing coronary artery surgery involving CPB.


METHODS
Blood samples were taken from periphery and coronary sinus of patients during CPB, and oxidative stress was evaluated by direct and indirect approaches. Direct detection of alkyl and alkoxyl radicals was assessed by electron spin resonance spectroscopy associated with the spin-trapping technique using alpha-phenyl-N-tert-butylnitrone.


RESULTS
The authors showed that the spin adduct concentration was not influenced by anesthesia and pre-CPB surgery. A rapid systemic increase of plasma spin adduct concentration occurred after starting CPB, and it stayed at a high concentration until the end of CPB. At the beginning of reperfusion period, radical oxygen species release was accelerated in the coronary sinus; however, it was not significant. A positive correlation was found between alpha-phenyl-N-tert-butylnitrone adduct concentrations and (1) the duration of CPB and (2) concentration of postoperative creatine phosphokinase of muscle band (CPK MB). Plasma vitamin E and C, ascorbyl radical, uric acid, thiol, plasma antioxidant status, and thiobarbituric acid reacting substances were also measured but did not give relevant indications, except for uric acid, which seemed to be consumed by the heart during reperfusion.


CONCLUSIONS
The results indicate that a systemic production of free radicals occurs during CPB that may overwhelm the production related to reperfusion of the ischemic heart. This systemic oxidative stress is likely to participate in secondary myocardial damage.
Clermont
Gaëlle
G
LPPCE Faculty of Medicine, Dijon, France. gaelle.clermont@u-bourgogne.fr
Vergely
Catherine
C
Jazayeri
Saëd
S
Lahet
Jean-Jacques
JJ
Goudeau
Jean-Jacques
JJ
Lecour
Sandrine
S
David
Michel
M
Rochette
Luc
L
Girard
Claude
C
D000368:Aged; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D004578:Electron Spin Resonance Spectroscopy; D005260:Female; D005609:Free Radicals; D006801:Humans; D008297:Male; D008875:Middle Aged; D015428:Myocardial Reperfusion Injury / Q000209:etiology; D009206:Myocardium / Q000378:metabolism*; D018384:Oxidative Stress; D014527:Uric Acid / Q000097:blood
D005609:Free Radicals; D014527:Uric Acid