Allopurinol does not increase free radical scavenging capacity during reperfusion in coronary artery bypass graft patients.
OBJECTIVE
Allopurinol protects the heart against ischaemic events during coronary artery bypass grafting (CABG), possibly because of its antioxidant properties. This double-blind study was designed to investigate whether allopurinol (1 g), given before cardiopulmonary bypass and prior to the opening of cross-clamping, has an antioxidant effect in CABG patients by measuring plasma total peroxyl radical scavenging capacity.


METHODS
Twenty-seven patients with stabile angina were randomized into allopurinol (n = 14) or placebo (n = 13) groups.


RESULTS
During 10 min reperfusion, plasma hypoxanthine and xanthine concentrations increased only in the allopurinol group, whereas uric acid concentrations decreased. Total peroxyl radical scavenging capacity (TRAP) decreased from the initial value at all measuring points in both groups.


CONCLUSIONS
The reducing effect of allopurinol on free radical generation cannot be seen in TRAP values, obviously because the uric acid concentration of plasma decreases markedly. The positive clinical effects of allopurinol in CABG patients may arise from its direct oxygen free radical scavenging function.
Tarkka
M R
MR
Division of Cardiovascular Surgery, Tampere University Hospital, University of Tampere, Finland. matti.tarkka@tays.fi
Kaukinen
S
S
Holm
P
P
Kaukinen
U
U
Sisto
T
T
Kataja
J
J
Huang
W Q
WQ
D000368:Aged; D000493:Allopurinol / Q000008:administration & dosage*; D000704:Analysis of Variance; D001026:Coronary Artery Bypass / Q000379:methods; D003327:Coronary Disease / Q000601:surgery*; D004311:Double-Blind Method; D016166:Free Radical Scavengers / Q000008:administration & dosage*; D005609:Free Radicals / Q000032:analysis; D006801:Humans; D019271:Hypoxanthine / Q000032:analysis*; D007262:Infusions, Intravenous; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care; D011336:Probability; D012016:Reference Values; D015424:Reperfusion; D012680:Sensitivity and Specificity; D014527:Uric Acid / Q000032:analysis*; D019820:Xanthine / Q000032:analysis*
D016166:Free Radical Scavengers; D005609:Free Radicals; D019820:Xanthine; D014527:Uric Acid; D019271:Hypoxanthine; D000493:Allopurinol